Tsunami Animation: Sumatra, 2004 PacificTWC 2014-12-01 | The magnitude 9.1 Great Sumatra-Andaman Earthquake of December 26, 2004, spawned the deadliest tsunami in history, killing more than 230,000 people in 14 countries around the Indian Ocean. More than half of those killed had lived in Acheh Province, Sumatra, where the tsunami rose as high as 30 m (100 ft.) and traveled more than 4 km (2.5 mi.) inland in this low-lying region.This earthquake began at its epicenter near northern Sumatra and moved the earth's crust an average of 15 m (50 ft.) as it ruptured northward for at least 1200 km (750 mi.), almost to the coast of Myanmar (Burma), over an 8-minute period. This distance is at least 200 km (125 mi.) longer than the length of fault that moved during the largest earthquake ever recorded, the magnitude 9.5 Great Chile Earthquake of 1960.This animation shows why this south-to-north rupture is important for understanding the behavior of this tsunami, and why such "progressive" rupture needs to be considered for future tsunami forecasting. If the earthquake had moved the fault along its entire length all-at-once it would have sent the largest tsunami waves perpendicular to the fault and so they would have passed south of Sri Lanka. The earthquake motion, however, started in the south and moved northward along the fault so the tsunami began radiating from near Sumatra before it could be generated near Myanmar, thus causing the largest tsunami waves to move in a different direction such that they strike Sri Lanka and Somalia directly, consistent with the tsunami waves actually observed in those countries.PTWC created this animation using the progressive rupture described by Chlieh et al. (2007) as input for their experimental forecast model, RIFT (Wang et al., 2012). For the first 30 minutes of simulated time the animation is centered over the northern Indian Ocean and moves at 30x normal speed to show the details of the tsunami as generated by this progressive rupture. The animation then speeds up to 1800x normal speed (1 sec. = 30 minutes simulated time) to carry the simulation forward a full 24 hours while it also zooms out and rotates the virtual globe to show the entire Indian Ocean. The waves then fade to an "energy map" showing the maximum calculated tsunami heights on the open ocean, then fade again to a map of the maximum calculated tsunami heights on the impacted coastlines.References:Chlieh, M., Avouac, J., Hjorleifsdottir, V., Song, T.A., Ji, C., Sieh, K., Sladen, A., Hebert, H., Prawirodirdjo, L., Bock., Y., & Galetzka, J. (2007) "Coseismic Slip and Afterslip of the Great Mw 9.15 Sumatra--Andaman Earthquake of 2004." Bulletin of the Seismological Society of America, 97 (1A), S152--S173, DOI: 10.1785/0120050631Wang, D., N.C. Becker, D. Walsh, G.J. Fryer, S.A. Weinstein, C.S. McCreery, V. Sardiña, V. Hsu, B.F. Hirshorn, G.P. Hayes, Z. Duputel, L. Rivera, H. Kanamori, K.K. Koyanagi, and B. Shiro (2012) "Real-time Forecasting of the April 11, 2012 Sumatra Tsunami" Geophysical Research Letters, 39, 6 pp., DOI: 10.1029/2012GL053081
120 Years of Earthquakes and Their Tsunamis: 1901-2020 PacificTWC 2021-04-10 | This animation shows every recorded earthquake in sequence as they occurred from January 1, 1901, through December 31, 2020, at a rate of 1 year per second. The earthquake hypocenters first appear as flashes then remain as colored circles before shrinking with time so as not to obscure subsequent earthquakes. The size of each circle represents the earthquake’s magnitude while the color represents its depth within the earth. This animation also highlights significant tsunamis generated by some of these earthquakes. When the following earthquakes appear they will also have their tsunami’s “energy map” that shows each tsunami's maximum modeled wave heights on the open ocean:8.8 — Ecuador-Columbia — 31 January 19068.5 — Atacama, Chile — 11 November 19228.4 — Kamchatka, Russia — 3 February 19238.4 — Sanriku, Japan — 2 March 19338.6 — Unimak Island, Aleutian Islands — 1 April 1946*9.0 — Kamchatka, Russia — 4 November 19528.6 — Andreanof Islands, Aleutian Islands — 9 March 1957*9.5 — Valdivia, Chile — 22 May 1960*9.2 — Prince William Sound, Alaska — 28 March 1964*8.7 — Rat Islands, Aleutian Islands — 4 February 19657.7 — Kalapana, Hawaii — 29 November 1975*8.4 — Southern Peru — 23 June 20019.1 — Sumatra, Indonesia — 26 December 2004*8.1 — Samoan Islands — 29 September 2009*8.8 — Maule, Chile — 27 February 2010*9.0 — Tohoku, Japan — 11 March 2011*7.9 — Haida Gwaii, Canada — 28 October 2012*(*tsunami animation also available on this YouTube channel)Note that while the great majority of all earthquakes occur at plate boundaries, these tsunami-causing earthquakes mostly occur at convergent plate boundaries. These boundaries, also called “subduction zones,” are where tectonic plates collide to produce megathrust earthquakes and are the regions where we expect future devastating tsunamis to come from. Other, much smaller earthquakes also occur away from plate boundaries such as those related to volcanic activity in Hawaii or those related to wastewater injection wells in Oklahoma.The animation concludes with a series of summary maps. The first one shows all of the earthquakes in this 120-year period. The next map shows only those earthquakes known to have produced a tsunami, and the map after that shows only those earthquakes that produced damaging tsunamis. The final map shows the plate boundary faults responsible for the majority of these earthquakes.The era of modern seismology—the scientific study of earthquakes—began with the invention of the seismograph in the late 19th Century and its deployment in instrument networks in the early 20th Century to record and measure earthquakes as they occur. Therefore, when the animation begins only the largest earthquakes will appear. They were the only ones that could be detected at great distances with the few instruments available at the time. But as time progressed, more and more seismographs were deployed and smaller and smaller earthquakes could be recorded. For example, the installation of these instruments in California in the 1930s creates the illusion of new earthquake activity there. Likewise, there appears to be a jump in the number of earthquakes globally in the 1970’s when seismology took another leap forward with advances in telecommunications and digital signal processing, a trend that continues today.-----Earthquakes from the USGS/NEIC Earthquake Catalog:earthquake.usgs.gov/earthquakes/searchTsunami sources from the NOAA/NCEI Tsunami Database:ngdc.noaa.gov/hazel/view/hazards/tsunami/event-search
Tsunami Forecast Model Animation: Three Tsunamis in One Day From the Tonga-Kermadec Subduction Zone PacificTWC 2021-03-17 | The Tonga-Kermadec Subduction Zone is a convergent boundary where the Pacific is subducted beneath the Australian Plate. It extends northeastward from New Zealand, through the Kermadec and Tonga Islands, and terminates just south of the Samoan Islands, covering a distance of about 2800 kilometers or 1800 statute miles. This boundary is also a source of large, shallow, undersea megathrust earthquakes and thus a source for tsunamis.On 4 March, 2021, three earthquakes along this boundary each generated a tsunami within a single day. In fact, they all occurred in a little more than six hours. The first struck northeast of Gisborne, New Zealand, with a magnitude of 7.3 at 13:27 UTC. New Zealand issued tsunami warnings for its own coasts, and tsunami waves as high as 28 cm or 11 in. were observed there. Just over four hours later the second earthquake struck in the Kermadec Islands, northeast of New Zealand’s main islands, with a magnitude of 7.4 at 17:41 UTC. It also produced a small tsunami, with measured wave heights of 36 cm or 14 inches at Raoul Island. That earthquake turned out to be a foreshock for a much larger event that struck the same area just under two hours later with a magnitude of 8.1 at 19:28 UTC. It prompted the Pacific Tsunami Warning Center (PTWC) to issue a Tsunami Warning (evacuation recommendation) for American Samoa, and a Tsunami Watch (possible hazard, analysis continues) to the State of Hawaii. Within an hour PTWC reduced the threat level to a Tsunami Advisory for American Samoa, meaning that a hazard remained offshore but that flooding was unlikely. About three hours later PTWC cancelled both the Advisory and the Watch when they determined that any hazard had passed. PTWC, however, continued to monitor the tsunami and provide hazard guidance to international emergency managers as it crossed the Pacific Ocean, standing down only after the waves had reached South America 20 hours after this third earthquake occurred. Sea-level gauges recorded the tsunami throughout the Pacific Ocean. Measured wave heights exceeded 55 cm or 22 in. at Norfolk Is., Australia and was nearly as high in the Galapagos Islands. In the United States the waves were about 18 cm or 7 in. high in Crescent City, CA and Kahului (Maui), HI.PTWC creates animations with the same tool that it uses to determine tsunami hazards in real time: the Real-Time Forecasting of Tsunamis (RIFT) forecast model. The RIFT model takes earthquake information as input and calculates how the waves move through the world’s oceans, predicting their speed, wavelength, and amplitude. This animation shows these values through the simulated motion of the waves and as they travel through the world’s oceans one can also see the distance between successive wave crests (wavelength) as well as their height (half-amplitude) indicated by their color. More importantly, the model also shows what happens when these tsunami waves strike land, the very information that PTWC needs to issue tsunami hazard guidance for impacted coastlines. From the beginning the animation shows all coastlines covered by colored points. These are initially a blue color like the undisturbed ocean to indicate normal sea level, but as the tsunami waves reach them they will change color to represent the height of the waves coming ashore, and often these values are higher than they were in the deeper waters offshore. The color scheme is based on PTWC’s warning criteria, with blue-to-green representing no hazard (less than 30 cm or ~1 ft.), yellow-to-orange indicating low hazard with a stay-off-the-beach recommendation (30 to 100 cm or ~1 to 3 ft.), light red-to-bright red indicating significant hazard requiring evacuation (1 to 3 m or ~3 to 10 ft.), and dark red indicating a severe hazard possibly requiring a second-tier evacuation (greater than 3 m or ~10 ft.).Toward the end of this simulated 30 hours of activity the wave animation will transition to the “energy map” of a mathematical surface representing the maximum rise in sea-level on the open ocean caused by the tsunamis, a pattern that indicates that the kinetic energy of the tsunami was not distributed evenly across the oceans but instead forms a highly directional “beam” such that the tsunami waves were higher in the middle of the “beam” of energy than on its sides. This pattern also generally correlates to the coastal impacts; note how those coastlines directly in the “beam” are hit by larger waves than those to either side of it.
40 Years of Earthquakes in the Contiguous United States: 1980 - 2020 PacificTWC 2020-04-05 | Every state and territory of the United State of America experiences earthquakes. In the contiguous states most of these earthquakes do not pose a tsunami risk as they do not lift or drop the seafloor. They are either too small, too far from a body of water, or move the underlying rock sideways. For these reasons two widely-felt earthquakes in March of 2020 also failed to generate tsunamis: the M5.7 Salt Lake City, Utah earthquake and the M6.5 Central Idaho earthquake. To put these two earthquakes in context this animation shows earthquakes in the contiguous United States for the previous forty years. Most earthquakes in the world, including those in the United States, are “interplate” earthquakes that occur at plate tectonic boundaries where large sections of the earth’s crust either grind past each other, pull apart, or slam together. With the exception of the Pacific Coast of southern California, the contiguous United States sits atop the North American Plate. This plate meets the Pacific Plate at the San Andreas Fault such that coastal California south of Mendocino rides atop the Pacific Plate, which moves northward relative to the rest of North America. North of Menocino, however, northern California, Oregon, and Washington State are colliding with the Juan de Fuca Plate (JdF) to produce a subduction zone capable of generating tsunamis with megathrust earthquakes. The last time this region produced a devastating tsunami, however, was 320 years ago. Offshore of the Pacific Northwest many earthquakes also occur along the boundaries between the Juan de Fuca Plate and the Pacific Plate. In the southeastern corner of the animation one more subduction zone also generates earthquakes where the North American Plate meets the Caribbean Plate at the Puerto Rico Trench.Earthquakes can also occur away from these plate boundaries throughout the contiguous United States. These are called “intraplate” earthquakes and they occur along faults within the North American continent. In recent years wastewater injection wells, a byproduct of hydraulic fracturing or “fracking” for hydrocarbon extraction, have also produced earthquakes in Oklahoma, north Texas, and eastern Wyoming. Some significant earthquakes in this 40 year period include:May 18, 1980 -- eruption of Mt. St. Helens (produced 820 ft. landslide-generated tsunami in Spirit Lake)Nov 8, 1980 -- M7.2 -- Northern CaliforniaMay 2, 1983 -- M6.5 -- Coalinga, CaliforniaOct 28, 1983 -- M7.3 -- Borah Peak, IdahoApr 24, 1984 -- M6.2 -- Morgan Hill, CaliforniaJul 21, 1986 -- M6.4 -- Eastern CaliforniaNov 23, 1987 -- M6.2 -- CaliforniaOct 17, 1989 -- M6.9 -- Loma Prieta, California (small tsunami)Aug 17, 1991 -- M6.2 -- Honeydew, CaliforniaAug 17, 1991 -- M7.0 -- Offshore of OregonApr 22, 1992 -- M6.3 -- Joshua Tree, CaliforniaApril 25, 1992 -- M7.2 -- Cape Mendocino, California (small tsunami)Jun 28, 1992 -- M6.5 -- Big Bear, CaliforniaJun 28, 1992 -- M7.3 -- Landers, CaliforniaSep 2, 1992 -- M5.8 -- St. George, UtahSep 20, 1993 -- M6.0 -- Klamath Falls, OregonJan 17, 1994 -- M6.7 -- Northridge, CaliforniaSep 1, 1994 -- M7.0 -- Northern California (small tsunami)Apr 14, 1995 -- M5.7 -- Marathon, TexasOct 16, 1999 -- M7.1 -- Hector Mine, CaliforniaFeb 28, 2001 -- M6.8 -- Nisqually, WashingtonDec 22, 2003 -- M6.5 -- San Simeon, CaliforniaJun 15, 2005 -- M7.2 -- Offshore Northern California (small tsunami)Sep 10, 2006 -- M5.8 -- Gulf of Mexico, FloridaFeb 21, 2008 -- M6.0 -- Wells, NevadaApr 4, 2010 -- M7.2 -- Baja California (Mexico)Jan 9, 2010 -- M6.5 -- Eureka, CaliforniaAug 23, 2011 -- M5.9 -- VirginiaMar 10, 2014 -- M6.8 -- Ferndale, CaliforniaAug 24, 2014 -- M6.0 -- South Napa, CaliforniaSep 3, 2016 -- M5.8 -- OklahomaDec 8, 2016 -- M6.6 -- Ferndale, CaliforniaJul 5, 2019 -- M7.1 -- Ridgecrest, CaliforniaAug 29, 2019 -- M6.3 -- Oregon CoastMar 18, 2020 -- M5.7 -- Salt Lake City, UtahMar 30, 2020 -- M6.5 -- Central IdahoThe National Tsunami Warning Center (NTWC) has the primary responsibility for issuing alerts for any tsunamis generated near the coastlines of the contiguous United States. NTWC will also alert these areas for dangerous tsunamis generated further away, such as the tsunami from Japan in 2011. Similarly the Pacific Tsunami Warning Center (PTWC) will alert the areas they serve--Hawaii, U.S. territories, and international partners--for any tsunami threat, including any tsunami generated off the coasts of the continental United States. These alerts will be posted to:tsunami.gov ----- Earthquake data from USGS/NEIC database:earthquake.usgs.gov/earthquakes/searchTsunami data from NOAA/NCEI Tsunami Database:ngdc.noaa.gov/hazard/tsu_db.shtmlPlate boundaries from UTIG’s PLATES project:https://ig.utexas.edu/marine-and-tectonics/plates-project/
30 Years of Earthquakes in Japan: 1990 - 2019 PacificTWC 2020-03-11 | The nation of Japan lies above a tectonic plate boundary called a “subduction zone” where the Pacific and Philippine Sea Plates grind beneath the Eurasian Plate. This type of plate boundary can create volcanoes, such as Japan’s many volcanoes including Mt. Fuji. Subduction zones can also generate megathrust earthquakes beneath the seafloor that cause devastating tsunamis. Many such earthquakes and tsunamis have struck Japan including the 9.1 magnitude earthquake that caused a devastating tsunami on 11 March 2011. This earthquake, the largest ever measured in Japan, produced six minutes of intense shaking starting at 14:46 local time. The tsunami that followed caused widespread devastation and over 17,000 deaths in Japan, where waves reached over 40 m or 130 ft. high. Outside of Japan the tsunami also killed one person in Papua, Indonesia and rose to greater than 5 m or 16 ft. in the Galapagos Islands (Ecuador), greater than 2m or 6.5 ft. in Indonesia, Russia's Kuril Islands, and in Chile, and rose to greater than 1 m or 3 ft. in Costa Rica, the Marquesas Islands (French Polynesia), Mexico, Papua New Guinea, and Peru. In the United States the tsunami rose to more than 5 m or 16 ft. in Hawaii, more than 2 m or 6.5 ft in California and Oregon, and more than 1 m or 3 ft. in the U.S. island territories of Midway and Saipan (Northern Mariana Islands). The tsunami also killed one person in Crescent City, California..This animation begins with a map of plate boundaries including the subduction zone between the Pacific plate and the Eurasian and Philippine Sea Plates. It will then show the earthquakes in sequence as they occur for 30 years beginning in the year 1990, about 21 years before the 2011 earthquake, and continues through the end of 2019, showing the nearly nine years of activity since then. Each earthquake is represented by a circle whose size indicated magnitude and color indicates depth within the earth. It will then conclude with a summary map showing all of the earthquakes in the animation. Several significant earthquakes, including tsunami-generating earthquakes, occurred during this period:12 July 1993 -- M7.7 -- Hokkaido, devastating tsunami at Okoshiri Island28 December 1994 -- M7.7 -- offshore Sanriku, non-damaging local tsunami17 January 1995 -- M7.3 -- Kobe, widespread earthquake damage4 May 1998 -- M7.5 -- Ryuku Islands25 September 2005 -- M8.3 -- Hokkaido, local tsunami15 November 2006 -- M8.3 -- Kuril Islands, ocean-crossing tsunami13 January 2007 -- M8.2 -- Kuril Islands11 March 2011 -- M9.1 -- Tōhoku, locally devastating ocean-crossing tsunami30 May 2014 -- M7.8 -- Bonin IslandsThe U.S. Pacific Tsunami Warning Center (PTWC) will issue tsunami alerts for any potentially tsunami-causing earthquake in the Japan region. These alerts will be posted to:tsunami.govThe seismic instrument networks that PTWC uses to detect and analyze earthquakes can also detect explosions, including nuclear weapons tests. The People’s Republic of Korea (PRK) conducted six underground nuclear tests between 2006 and 2017. This animation includes these tests as black circles scaled according to their equivalent earthquake magnitudes.-----To see an animation of the 2011 Japan tsunami, please watch:youtu.be/jH3-hQjTGDQTo see how subduction zones make tsunamis, please watch:youtu.be/UCr_8E6hXTUTo see a comparison of the relative sizes of some historic earthquakes, please watch: youtu.be/sTvtKUb-RsYTo see how seismologists distinguish between earthquakes and explosions, please watch:youtu.be/BwxVDaUrsEU -----Tsunami data from NOAA’s Global Historical Tsunami Database:ngdc.noaa.gov/hazard/tsu_db.shtmlEarthquake Data Source: United States Geological Survey (USGS)/National Earthquake Information Center (NEIC) searchable catalog:earthquake.usgs.gov/earthquakes/search Plate boundaries from UTIG’s PLATES project:https://ig.utexas.edu/marine-and-tectonics/plates-project/
20 Years of Earthquakes in Chile: 2000 - 2019 PacificTWC 2020-02-21 | The nation of Chile lies above a tectonic plate boundary called a “subduction zone” where the Nazca and Antarctic Plates grind beneath the South American Plate. This type of plate boundary can create mountain belts and volcanoes, such as those that make up the Andes that stretch the entire length of the South American continent. Subduction zones can also generate megathrust earthquakes beneath the seafloor that cause devastating tsunamis. Many such earthquakes and tsunamis have struck Chile including the 8.8 magnitude earthquake that caused a devastating tsunami on 27 January 2010. This earthquake, the largest to strike Chile in 50 years, produced three minutes of intense shaking at 3:34 in the morning, killing over 400 people. The tsunami that followed caused the greatest devastation and 124 deaths on the Chilean mainland, where waves reached as high as 29 m (95 ft.). On Chile’s Juan Fernandez Islands the waves grew to over 18 m (60 ft.), killing at least 4, and over 4 m (14 ft.) at Rapa Nui (Isla de Pascua/Easter Island). Outside of Chile the tsunami wave heights exceeded 1 m or 3 ft. in the Marquesas Islands (French Polynesia), New Zealand, the Kuril Islands (Russia), and in the United States in California and Hawaii. It caused an estimated $30 billion in damage in Chile, and minor damage in San Diego, California and in Tohoku, Japan.This animation begins with a map of plate boundaries including the subduction zone between the South American plate and the Nazca and Antarctic Plates. It will then show the earthquakes in sequence as they occur for 20 years beginning in the year 2000, about 10 years before the 2010 earthquake, and continues through the end of 2019, showing the nearly ten years of activity since then. It will then conclude with a summary map showing all of the earthquakes in the animation. Several tsunami-generating earthquakes occurred during this period and are visible in this animation:23 June 2001 -- M8.4 -- southern Peru27 February 2010 -- M8.8 -- Maule, Chile1 April 2014 -- M8.2 -- Iquique, Chile16 September 2015 -- M8.3 -- Illapel, ChileThe U.S. Pacific Tsunami Warning Center (PTWC) will issue tsunami alerts for any potentially tsunami-causing earthquake in the Chile region. These alerts will be posted to:tsunami.gov -----To see an animation of the 2010 Chile tsunami, please watch:youtu.be/EBgGsmKXD-k To see how subduction zones make tsunamis, please watch:youtu.be/UCr_8E6hXTUTo see a comparison of the relative sizes of some historic earthquakes, please watch:youtu.be/sTvtKUb-RsY-----Tsunami data from NOAA’s Global Historical Tsunami Database:ngdc.noaa.gov/hazard/tsu_db.shtmlEarthquake Data Source: United States Geological Survey (USGS)/National Earthquake Information Center (NEIC) searchable catalog:earthquake.usgs.gov/earthquakes/searchPlate boundaries from UTIG’s PLATES project:https://ig.utexas.edu/marine-and-tectonics/plates-project/
Puerto Rico Earthquake Sequence: December 2019 - January 2020 PacificTWC 2020-02-02 | The start of 2020 saw some significant earthquake activity in the Puerto Rico region. A M6.4 earthquake struck the southern coast of Puerto Rico on January 7, killing at least one person and damaging many structures including the homes of thousands of people. It also produced a small, non-hazardous tsunami. It was preceded by a series of foreshocks in late December and followed by a sequence of aftershocks that continues today (February 2, 2020). This animation therefore begins on December 1, 2019, to show the typical level of earthquake activity prior to the start of the earthquake sequence on December 28. It proceeds forward in time at a rate of one day per second through the end of January 31.Puerto Rico lies above an active plate boundary between the North American and Caribbean Plates. In fact, it makes up part of a “microplate” sandwiched between these two larger plates. Relative motions between these plates cause earthquakes at their boundaries. To the north the North American plate grinds beneath Puerto Rico in a subduction zone, a type of plate boundary that can produce megathrust earthquakes with large vertical motions that can cause tsunamis. A mirror image of this structure lies to the south of Puerto Rico such that the Caribbean Plate likewise grinds beneath the island. As it is squeezed between these megathrust fault systems Puerto Rico itself deforms with complex faulting that produced the earthquake sequence in this animation.For an earthquake to pose a tsunami hazard it has to be able to significantly move the sea floor in a vertical direction, either by suddenly dropping or popping up. Therefore, when an earthquake occurs PTWC scientists need to rapidly determine an earthquake’s location, including its depth. Is it on land or under the ocean? Is it shallow enough to move the seafloor, or is it so deep that it doesn’t pose a risk? They then determine its magnitude, since a larger earthquake will move more of the sea floor and over a larger area. These parameters can be determined within a matter of minutes. But over the course of the first hour following an earthquake they will continue to analyze their data and they may also be able to determine which direction the seafloor moved. It may have moved primarily in a vertical direction (either up or down), and thus pose a greater tsunami risk. Or it may have moved mostly sideways, posing a lesser tsunami hazard. Once these scientists have this information they can use it to better predict how dangerous a tsunami may be, but until they can figure it out they will assume the worst-case scenario of maximum vertical motion. If they figure out later that the earthquake is something else, such as an earthquake that mostly moved sideways, they may downgrade or cancel their tsunami alert. A graphical way to show this sense of motion for earthquakes is the “focal mechanism” often informally referred to as a “beach ball.” This animation includes these symbols to show which direction the largest earthquakes moved. Thankfully these largest earthquakes did not pose a significant tsunami hazard because they were not big enough and/or moved sideways. These five earthquakes are:January 6, 2020 10:32Z -- M5.7 -- strike-slip (sideways) motionJanuary 7, 2020 8:24Z -- M6.4 -- normal (downward) motion, 6 cm/2.4 in. tsunamiJanuary 7, 2020 8:34Z -- M5.6 -- normal (downward) motionJanuary 7, 2020 11:18Z -- M5.8 -- strike-slip (sideways) motionJanuary 11, 2020 12:55Z -- M5.9 -- strike-slip (sideways) motionThe U.S. Pacific Tsunami Warning Center (PTWC) will issue tsunami alerts for any potentially tsunami-causing earthquake in the Puerto Rico region. These alerts will be posted to:tsunami.govFor more information about mitigating tsunami hazards in this region please see the Caribbean Tsunami Warning Program (CTWP):weather.gov/ctwpFor a more thorough explanation of focal mechanisms, please watch: youtu.be/MomVOkyDdLoTo see how subduction zones make tsunamis, please watch:youtu.be/UCr_8E6hXTU-----Earthquake Data Source: United States Geological Survey (USGS)/National Earthquake Information Center (NEIC) searchable catalog:earthquake.usgs.gov/earthquakes/searchFocal Mechanisms Source: Global Centroid Moment Tensor Project (GCMT):globalcmt.orgPlate Boundary from UTIG’s PLATES Project:https://ig.utexas.edu/marine-and-tectonics/plates-project/
Earthquakes of the Caribbean: 2001 - 2020 PacificTWC 2020-01-31 | January 2020 saw some significant earthquake activity in the Caribbean Sea region. A M6.4 earthquake struck the southern coast of Puerto Rico on January 7 and generated a small, non-destructive tsunami. An active swarm of aftershocks continues today (January 30, 2020). A much larger M7.7 earthquake occurred between Cuba and Jamaica on January 28 and thankfully did not generate a damaging tsunami either. Though this earthquake was quite large, it moved the seafloor horizontally rather than vertically. This animation begins with the start of the 21st Century showing all earthquakes of M4 or larger as they happened and concludes with these latest earthquakes.The Caribbean Sea lies over the Caribbean Plate, a section of the earth’s crust bounded by active faults separating it from other tectonic plates. These other plates include the North American Plate to the north and east and the Pacific Plate to the west. Relative motions between these plates cause earthquakes at their boundaries. Most of the east-west trending boundaries of the Caribbean Plate are “strike-slip” or transform faults such that the plates move past each other horizontally, similar to the famous San Andreas Fault in California. Since they move sideways they do not usually cause earthquakes that move the ocean water above them, though they can trigger landslides that generate tsunamis, such as the M7.0 earthquake in Haiti in 2010. But the boundaries of the Caribbean Plate that run northwest-southeast in Central America and in the Leeward Islands are subduction zones, a type of plate boundary that can produce megathrust earthquakes with large vertical motions that can cause tsunamis, such as M7.3 earthquake in El Salvador in 2012.The Pacific Tsunami Warning Center (PTWC) will issue tsunami alerts for any potentially tsunami-causing earthquake in the Caribbean region. These will be posted to: tsunami.govFor more information about mitigating tsunami hazards in this region please see the Caribbean Tsunami Warning Program (CTWP): weather.gov/ctwp-----Earthquake Data Source: United States Geological Survey (USGS)/National Earthquake Information Center (NEIC) searchable catalog: earthquake.usgs.gov/earthquakes/searchPlate Boundaries Source: UTIG PLATES Project: https://ig.utexas.edu/marine-and-tectonics/plates-project/
Five Years of Earthquakes in Southern Alaska: 2015 - 2019 PacificTWC 2020-01-25 | Alaska lies above a tectonic plate boundary called a “subduction zone” such that the Pacific Plate grinds beneath the North American Plate. This type of plate boundary can create volcanoes, such as Redoubt, Augustine, and Katmai. Subduction zones can also produce megathrust earthquakes with large vertical motions that cause devastating tsunamis, such as the M9.2 Great Alaska Earthquake that struck Prince William Sound in 1964. A subduction zone boundary will also produce many smaller earthquakes, and they can be seen in this animation as the earthquakes that become deeper and deeper the further away they occur from the plate boundary, the Aleutian Trench. Meanwhile, both plates also host their own shallow earthquakes that result from many smaller faults that form as they are being squeezed and sheared by their collision in this subduction zone. In other words, there is one gigantic fault--the subduction zone megathrust--and many smaller faults on both the Pacific and North American Plates that can produce earthquakes. For an earthquake to pose a tsunami hazard it has to be able to significantly move the sea floor in a vertical direction, either by suddenly dropping or popping up. Therefore, when an earthquake occurs the scientists in the tsunami warning centers need to rapidly determine an earthquake’s location, including its depth. Is it on land or under the ocean? Is it shallow enough to move the seafloor, or is it so deep that it doesn’t pose a risk? They then determine its magnitude, since a larger earthquake will move more of the sea floor and over a larger area. These parameters can be determined within a matter of minutes. But over the course of the first hour following an earthquake they will continue to analyze their data and they may also be able to determine which direction the seafloor moved. It may have moved primarily in a vertical direction (either up or down), and thus pose a greater tsunami risk. Or it may have moved mostly sideways, posing a lesser tsunami hazard. Once these scientists have this information they can use it to better predict how dangerous a tsunami may be, but until they can figure it out they will assume the worst-case scenario of maximum vertical motion. If they figure out later that the earthquake is something else, such as an earthquake that mostly moved sideways, they may downgrade or cancel their tsunami alert. A graphical way to show this sense of motion for earthquakes is the “focal mechanism” sometimes informally referred to as a “beach ball.” These symbols are included in this animation to show which direction some of the earthquakes moved, especially the larger ones. Note that the locations of the focal mechanisms do not exactly coincide with the circles representing the hypocenters. That is because earthquake rupture starts in one spot then moves across the surface of a fault plane. The hypocenter circles represent where this rupture starts, whereas the focal mechanisms are positioned such that they represent the location of the average of all of the motion from the earthquake. Imagine you’re unzipping your jacket: the hypocenter is where the slider was at the top of your jacket, while the centroid will be somewhere around the middle of the zipper.Thankfully the largest earthquakes that occurred in the five year period covered by this animation did not pose a significant tsunami hazard because they were too far inland, too deep, not big enough, or moved sideways. Three particularly large earthquakes occurred during this five-year period:Jan 24, 2016 -- M 7.1 -- east of Old Iliamna, Alaska -- deep with sideways and downward motionJan 23, 2018 -- M 7.9 -- southeast of Kodiak -- shallow but with sideways motion (small tsunami)Nov 30, 2018 -- M 7.1 -- Anchorage -- deep and inland with downward motion but damagingThe U.S. Pacific Tsunami Warning Center (PTWC) and the U.S. National Tsunami Warning Center (NTWC) will issue tsunami alerts for any potentially tsunami-causing earthquake in the Alaska region. These alerts will be posted to:tsunami.govFor a more thorough explanation of focal mechanisms, please watch:youtu.be/MomVOkyDdLoTo see how subduction zones make tsunamis, please watch:youtu.be/UCr_8E6hXTU -----Earthquake Data Source: United States Geological Survey (USGS)/National Earthquake Information Center (NEIC) searchable catalog:earthquake.usgs.gov/earthquakes/searchFocal Mechanisms Source: Global Centroid Moment Tensor Project (GCMT):globalcmt.orgPlate Boundary from UTIG’s PLATES Project:https://ig.utexas.edu/marine-and-tectonics/plates-project/Fault Lines from the State of Alaska’s Division of Geologic and Geophysical Surveys (DGGS):dggs.alaska.gov
Earthquakes of Indonesia: 2004 - 2019 PacificTWC 2019-12-26 | On 26 December 2004 the third-largest earthquake ever recorded struck the coast of Sumatra, Indonesia, with a magnitude of 9.1. It generated the deadliest tsunami in history--and one of the deadliest natural disasters--killing nearly 228,000 people in 14 countries.Indonesia lies above a tectonic plate boundary called a “subduction zone” where the Indo-Australian Plate grinds beneath the Eurasian Plate. Subduction zones can produce megathrust earthquakes with large vertical seafloor motions that cause devastating tsunamis such as the one in 2004. This type of plate boundary can also give rise to volcanoes, and Indonesia is home to many well-known active volcanoes, such as Krakatoa, which can also generate tsunamis with their eruption and collapse.This animation covers the 15 year period since the devastating earthquake and tsunami of 2004. It begins with a map of plate boundaries, showing the complexity of the region, and highlighting the sources of two recent, unusual tsunamis: the Palu Fault that generated a deadly local tsunami from a sideways-moving strike-slip earthquake (and possibly landslides) within a narrow inlet, and the Anak Krakatau volcano (within Krakatoa’s caldera) that collapsed during an eruption to produce another locally devastating tsunami. The animation will then show the earthquakes in sequence as they occur from 2004 through 2009, ending with a summary map showing all of the earthquakes in the animation. Some significant events that occurred during this period include:26 December 2004 -- M9.1 -- Sumatra-Andaman Islands, source of Indian Ocean tsunami 28 March 2005 -- M8.6 -- Nias–Simeulue (Sumatra), killed more than 900 and caused a small tsunami27 January 2006 -- M7.6 -- Banda Sea; almost 400 km deep17 July 2006 -- M7.7 -- Pangandaran (Java); a slow-rupture earthquake with a low shaking intensity that produced a devastating tsunami, approx. 700 dead12 September 2007 -- M7.9, M8.4, and M7.0 -- Sumatra; 23 dead, small tsunami3 January 2009 -- M7.7 & M7.4 -- Papua; 4 dead30 September 2009 -- M7.6 -- Sumatra; more than 1000 dead6 April 2010 -- M7.8 -- Sumatra; small tsunami25 October 2010 -- M7.8 -- Mentawai Islands (Sumatra); devastating local tsunami, more than 400 dead11 April 2012 -- M8.6 & M8.2 -- Indian Ocean; largest strike-slip events ever recorded, small tsunami2 March 2016 -- M7.8 -- Indian Ocean; strike-slip28 September 2018 -- M7.5 -- Palu (Sulawesi); strike-slip with locally damaging tsunami, over 4000 dead (mostly from the earthquake)22 December 2018 -- Anak Krakatau volcanic eruption and collapse causing a submarine landslide and tsunami (no significant earthquake so not visible in the animation); more than 400 deadFrom 2005 to 2013 the Pacific Tsunami Warning Center (PTWC) provided tsunami warning services to the nations of the Indian Ocean. Today Indonesia, Australia, and India play that role. Indonesia: http://rtsp.bmkg.go.id Australia: http://www.bom.gov.au/tsunami/ India: https://incois.gov.in/tsunami/eqevents.jsp-----To see an animation of the 2004 Indian Ocean tsunami, please watch:youtu.be/n1VmbgsM-zETo see a comparison of the relative sizes of some historic earthquakes, please watch:youtu.be/sTvtKUb-RsYTo see how subduction zones make tsunamis, please watch: youtu.be/UCr_8E6hXTU-----Earthquake Data Source: United States Geological Survey (USGS)/National Earthquake Information Center (NEIC) searchable catalog:earthquake.usgs.gov/earthquakes/searchPlate boundaries from UTIG’s PLATES project:https://ig.utexas.edu/marine-and-tectonics/plates-project/
Earthquakes of Alaska: 1918 - 2019 PacificTWC 2019-12-01 | The M7.1 earthquake that occurred under Anchorage, Alaska, on November 30, 2018, was the largest earthquake to impact the city in 54 years. It was not, however, the largest recorded earthquake there. That distinction goes to the March 28, 1964, M9.2 Great Alaskan Earthquake (a.k.a. the Good Friday Earthquake) that struck the region as the largest earthquake ever recorded in North America, and the second-largest earthquake recorded anywhere. It in fact released more than 1000 times as much energy as the 2018 earthquake and generated a devastating tsunami.Alaska and its Aleutian Islands lie above a tectonic plate boundary called a “subduction zone” where the Pacific Plate grinds beneath the North American Plate. This type of plate boundary can create volcanoes, such as those that make up the Aleutian Islands that stretch from Kamchatka, Russia to the Alaska Peninsula. Subduction zones can also produce megathrust earthquakes with large vertical motions that cause devastating tsunamis. Alaska and the Aleutian Islands have been the source of many such earthquakes and tsunamis in the more than 100 years of scientific measurement of these phenomena, and this animation shows all of the recorded seismic activity in this region from 100 years before the 2018 Anchorage earthquake up until the present day*Some significant earthquakes shown in this animation include:April 1, 1946 -- M8.6 -- Unimak Island, Aluetian Is. (damaging/deadly tsunami)Aug 22, 1949 -- M8.0 -- Haida Gwaii (Queen Charlotte Island), Canada (tsunami)Nov 4, 1952 -- M9.0 -- Kamchatka, Russia (damaging/deadly tsunami)Mar 3, 1957 -- M8.6 -- Andreanof Islands, Aleutian Islands (damaging tsunami)Jul 10, 1958 -- M7.8 -- Southeastern Alaska (Lituya Bay rockfall and megatsunami)Mar 28, 1964 -- M9.2 -- Prince William Sound (damaging/deadly tsunami)Feb 2, 1965 -- M8.7 -- Rat Islands, Aleutian Is. (damaging tsunami)Nov 3, 2002 -- M7.9 -- Central Alaska (Denali Fault)Oct 28, 2012 -- M7.8 -- Haida Gwaii (Queen Charlotte Island), Canada (tsunami)May 24, 2013 -- M8.3 -- Sea of Okhotsk (very deep: 598 km / 372 mi.)Jan 23, 2018 -- M7.9 -- southeast of Kodiak IslandNov 30, 2018 -- M7.1 -- Anchorage (significant damage, no deaths)The U.S. Pacific Tsunami Warning Center (PTWC) and the U.S. National Tsunami Warning Center (NTWC) will issue tsunami alerts for any potentially tsunami-causing earthquake in the Alaska region. These alerts will be posted to:tsunami.gov To see a comparison of the relative sizes of some historic earthquakes, please watch:youtu.be/sTvtKUb-RsYTo see how subduction zones make tsunamis, please watch:youtu.be/UCr_8E6hXTU-----Earthquake Data Source: United States Geological Survey (USGS)/National Earthquake Information Center (NEIC) searchable catalog:earthquake.usgs.gov/earthquakes/search-----*Please note that this animation shows every earthquake in the USGS/NEIC catalog for this region. As the animation moves forward in time so too does the science of seismology with the continual addition of newer and better instruments. As the animation approaches the present day these instrument networks are able to detect smaller and smaller earthquakes, creating the illusion of increasing activity. This effect is especially noticeable in 1973 and again in 2002. In reality these smaller earthquakes have always occurred, but the technology has only recently been able to detect them.
Earthquakes of the Caribbean: 1918 - 2019 PacificTWC 2019-10-02 | The M6.0 earthquake that occurred near Puerto Rico on September 24, 2019, was the largest earthquake to strike the U.S. territory in five years. It was not, however, the largest recorded earthquake there. That distinction goes to the July 7, 1943, M7.7 earthquake that thankfully did not generate a tsunami. Other earthquakes, and sometimes the landslides they cause, have produced tsunamis throughout the Caribbean Sea region, including one in Puerto Rico in 1918. Therefore this animation begins in 1918 and covers the 101 years up until the present day to show all of the recorded seismic activity in this region over that time period.*The Caribbean Sea lies over the Caribbean Plate, a section of the earth’s crust bounded by active faults separating it from other tectonic plates. These other plates include the North American Plate to the north and east and the Pacific Plate to the west. Relative motions between these plates cause earthquakes at their boundaries. Most of the east-west trending boundaries are “strike-slip” or transform faults such that the plates move past each other horizontally, similar to the famous San Andreas Fault in California. Since they move sideways they do not generally cause earthquakes that move the ocean water above them, though they can trigger landslides that generate tsunamis, such as in Haiti in 2010. But the boundaries of the Caribbean Plate that run northwest-southeast in Central America and the Leeward Islands are subduction zones, a type of plate boundary that can produce megathrust earthquakes with large vertical motions that can cause devastating tsunamis, such as the pair of devastating Dominican Republic earthquakes in 1946.Some earthquakes in this region that produced significant tsunamis include:Oct 11, 1919 -- M7.1 -- Puerto Rico (tsunami killed 140)Aug 5, 1946 -- M7.5-- Dominican Republic (tsunami killed 1790)Aug 8, 1946 -- M7.0 -- Dominican Republic (tsunami killed 75)Apr 22, 1991 -- M 7.6 -- Costa Rica (tsunami killed 3)Sep 2, 1992 -- M7.7 -- Nicragua (tsunami killed 170 on the Pacific coast)Jan 12, 2010 -- M7.0 -- Haiti (tsunami killed 7)Aug 27, 2012 -- M7.3 -- El Salvador (Pacific Coast, no deaths)Today the Pacific Tsunami Warning Center (PTWC) will issue tsunami alerts for any potentially tsunami-causing earthquake in the Caribbean region. These will be posted to:tsunami.gov For more information about mitigating tsunami hazards in this region please see the Caribbean Tsunami Warning Program (CTWP):weather.gov/ctwpEarthquake Data Source: United States Geological Survey (USGS)/National Earthquake Information Center (NEIC) searchable catalog:earthquake.usgs.gov/earthquakes/search-----*Please note that this animation shows every earthquake in the USGS/NEIC catalog for this region. As the animation moves forward in time so too does the science of seismology with the continual addition of newer and better instruments. As the animation approaches the present day these instrument networks are able to detect smaller and smaller earthquakes, creating the illusion of increasing activity. This effect is especially noticeable starting in 1973, and in Puerto Rico in particular starting in the mid-1990s. In reality these smaller earthquakes have always occurred, but the technology has only recently been able to detect them.
Earthquakes of Cascadia: 1979 - 2019 PacificTWC 2019-09-04 | The widely-felt M6.3 earthquake of August 29, 2019 on the Blanco Fracture Zone was only the most recent of many moderate-size earthquakes to strike this region off of the Oregon coast. As this animation shows, such earthquakes are common along the boundaries of the Juan de Fuca plate with the Pacific Plate, which also includes the Juan de Fuca Ridge, the Gorda Ridge, and the Mendocino Fracture Zone. Fortunately these events rarely pose a tsunami hazard since the largest of these earthquakes tend to have strike-slip mechanisms that move the seafloor mostly sideways with little disruption to the ocean above.The Juan de Fuca Plate meets the North American Plate, however, with a very different sort of plate boundary: a subduction zone. This plate boundary can produce megathrust earthquakes with large vertical motions that cause devastating tsunamis. It has been more than 300 years since the last time the Cascadia Subduction Zone generated such destruction, on January 26, 1700. This subduction zone also created the volcanoes of the High Cascades, stretching from northern California into southern British Columbia. To put the recent earthquake in context this animation begins 40 years earlier, in 1979. In that time frame 10 earthquake of M6.0 or larger occurred on the Blanco FZ and more than a dozen along the Mendocino FZ, some with M7.0 or larger. The fracture zones off of Vancouver Island have also produced numerous earthquakes larger than M6.0, with one as large at M6.8. The largest earthquake on the Cascadia Subduction Zone in the last 40 years was the M6.8 Nisqually Earthquake in southern Puget Sound on February 28, 2001. The volcanic activity of Mt. St. Helens is also visible in 1980-1982 and 2004-2008. As the area covered by the animation extends over North America, it also includes activity unrelated to Cascadia, such as the October 28, 1983, M6.9 southern Idaho earthquake and numerous small events associated with the Yellowstone Caldera.Please note that this animation shows every earthquake in the USGS/NEIC catalog for this region. As the animation moves forward in time so too does the science of seismology with the continual addition of newer and better instruments. As the animation approaches the present day these instrument networks are able to detect smaller and smaller earthquakes, creating the illusion of increasing activity. In reality these smaller earthquakes have always been there, but the technology has only recently been able to detect them.Earthquake Data Source: United States Geological Survey (USGS)/National Earthquake Information Center (NEIC) searchable catalog: earthquake.usgs.gov/earthquakes/search
Earthquakes of California: 1989 - 2019 PacificTWC 2019-07-22 | On July 5, 2019, the largest earthquake to strike California in 20 years occurred near the town of Ridgecrest with a moment magnitude of 7.1 following a magnitude 6.4 foreshock on the previous day. The National Tsunami Warning Center (NTWC) in Palmer, Alaska, has the primary responsibility for determining whether earthquakes in the continental United States, including California, pose a tsunami threat. The Pacific Tsunami Warning Center (PTWC) also monitors these earthquakes in case it has to provide back-up service for NTWC . While California produces many earthquakes, most are too small, too far from the ocean, and/or move the earth in such a way that they are unlikely to produce tsunamis, though there are exceptions. This animation covers a period of 30 years to put the Ridgecrest earthquakes in context and show how they compare with other recent, noteworthy earthquakes including:Oct 10, 1989 -- Loma Prieta -- 6.9 MwApr 25, 1992 -- Cape Mendocino -- 7.2 Mw (caused a small tsunami)Jun 28, 1992 -- Landers -- 7.3 MwJan 17, 1994 -- Northridge -- 6.7 MwOct 16, 1999 -- Hector Mine -- 7.1 MwDec 22, 2003 -- San Simeon -- 6.6 MwApr 4, 2010 -- Baja California (Mexico) -- 7.2 MwAug 24, 2014 -- South Napa -- 6.0 MwJul 4, 2019 -- Ridgecrest -- 6.4 MwJul 5, 2019 -- Ridgecrest -- 7.1 MwFor tsunami alerts from NTWC and PTWC please visit:tsunami.govEarthquake data from USGS/NEIC database:earthquake.usgs.gov/earthquakes/search
Kīlauea Volcano’s Earthquakes and Eruptions: April - August, 2018 PacificTWC 2019-05-04 | The NWS’s Pacific Tsunami Warning Center (PTWC) mitigates tsunami hazards in Hawai‘i produced by large, distant earthquakes throughout the Pacific Ocean, but PTWC also issues warnings for tsunamis generated by earthquakes within the State of Hawai‘i itself. The last such dangerous tsunami was generated by a 7.7 magnitude earthquake on the Big Island of Hawai‘i in 1975. Small earthquakes generated by volcanic activity are far more common, and typically have a magnitude less than 3.0 and occur a few times a day. That rate changed on the afternoon of April 30, 2018, when an earthquake “swarm” began within Kīlauea Volcano such that earthquakes began to occur far more frequently, about 100 per day.This animation begins a month earlier on April 1 to start with a more typical earthquake pattern and proceeds forward in time at a rate of one day per second of animation time. Circles indicate the locations of earthquakes as they occur, with their sizes indicating their magnitudes and their colors representing their depths. Three days before the swarm began the lava within the "Overlook crater" inside of Halema‘uma‘u overflowed. Then on April 30 the 35-year-old Puʻu ʻŌʻō eruption ceased and its cone partially collapsed. This event coincided with the start of a swarm of volcanic earthquakes on Kīlauea's East Rift Zone, a feature extending from the volcano's summit that carries magma underground through its flanks. Eruptions can take place anywhere along this rift zone as well as at the volcano's summit. Starting with that collapse earthquake activity moved northeast along the East Rift Zone away from Puʻu ʻŌʻō, suggesting the movement of magma below ground in this direction. Magma reached the surface and erupted as lava on the afternoon of May 3, eventually building channelized lava flows, destroying about 700 homes, and covering more than 12 square miles including Kapoho Bay. In this animation a growing orange field represents these lava flows.The eruption of lava from the East Rift Zone drew magma away from its reservoir under Kīlauea's summit. Lava began to drain from the “Overlook crater” on May 2 and by May 15 its lava lake had dropped hundreds of feet and was producing explosions, some of which were strong enough to register as magnitude 5.0 earthquakes and send ash clouds to 30,000 ft. above sea level. By the end of May, however, the walls of Halema‘uma‘u had begun to collapse, thus widening itself and burying its “Overlook crater” and ending the explosive activity. Not only was Halema‘uma‘u Crater collapsing, but the entire floor of Kīlauea Caldera was dropping as magma continued to drain from the summit to feed the flank eruption, and this “deflation” of the volcano’s summit generated an unprecedented level of seismic activity with a peculiar pattern. To help illustrate this pattern this animation includes charts showing some statistics about the earthquake activity shown here. The top graph shows the earthquakes’ magnitudes as they occur. The bottom graph shows the total number of earthquakes per hour. On April 30 the frequency of earthquakes increased to about 100 per day with their magnitudes exceeding 4.0. The largest earthquake struck on the afternoon of May 4 with a magnitude of 6.9. It produced numerous aftershocks and a small, but non-life-threatening, tsunami. This largest earthquake also moved the flank of Kīlauea Volcano as much as 20 inches seaward. With the subsidence of Kīlauea Caldera and the collapse of Halema‘uma‘u the number of earthquakes dramatically increased and by June 15 there were more than 700 per day. These earthquakes would repeatedly grow in number and culminate with a magnitude 5.0+ event every one to two days, pause for a few hours, then start over again. This cycle repeated 62 times with the last of the 5.0+ events on August 2 and ceasing altogether two days later when seismicity suddenly returned to normal background levels, coinciding with the end of the vigorous eruption of lava from the East Rift Zone.Though PTWC monitors all earthquakes in Hawai‘i , including this volcanic activity, the primary responsibility for mitigating volcanic hazards in the State of Hawai‘i rests with the USGS’s Hawaiian Volcano Observatory who publishes updates and advises local emergency managers.-----The Hawaiian Volcano Observatory:volcanoes.usgs.gov/observatories/hvoOrigin of earthquakes in the Hawaiian Islands:youtu.be/H0bnaV35SnoComparison of historic earthquakes in Hawai‘i by magnitude:youtu.be/k4bUliVLoOYEarthquake activity throughout the Hawaiian Islands:youtu.be/7wQkJ3THyN0Recent earthquake activity on or near the Big Island of Hawaiʻiyoutu.be/mHCIxd3et5k1975 Hawai‘i Island tsunami:youtu.be/0Ho0BzF2eCY
Earthquakes of Hawaiʻi Island: 2013 - 2018 PacificTWC 2019-04-26 | This animation shows earthquakes on or near the Big Island of Hawaiʻi in sequence as they occurred from January 1, 2012, through December 31, 2018. Prior to 2018 the animation proceeds at a speed of one month per second, but shifts into a “slow motion” rate of one week per second for 2018 to better show the extraordinary seismic activity associated with that year’s new eruptive activity on Kīlauea Volcano, including the M6.9 earthquake on May 4 that generated a small observable, but non-life-threatening, tsunami. This animation starts in 2013 when the NEIC catalog begins to include many smaller earthquakes as it does today, thus we can see what a typical level of earthquake activity looks like prior to the elevated activity of 2018.The earthquake hypocenters first appear as flashes then remain as colored circles before shrinking with time so as not to obscure subsequent earthquakes. The initial size of the circle represents the earthquake’s magnitude while the color represents its depth within the earth. The animation concludes with a summary map showing all of the quakes used in this presentation.Instead of plate tectonics, three principal mechanisms cause seismic activity within the Hawaiian Islands. First, movement of magma within volcanoes and other volcanic phenomena (such as explosions) can cause ground shaking. Second, motion along faults within the volcanoes and at the boundary between the volcanoes and the old ocean floor they sit on can generate earthquakes, including the largest ones recorded in Hawaiʻi. And third, the weight of these enormous volcanoes bends the lithosphere (oceanic crust + brittle upper mantle) and sometimes it will break, causing earthquakes. In this animation events recorded within the volcano tend to be shallower and will have “warmer” (red, orange, yellow) colors, while those within the lithosphere tend to be deeper and have “cooler” (blue to violet) colors. For a fuller explanation of the origin of earthquakes in Hawaiʻi please watch this video: youtu.be/H0bnaV35SnoFor a comparison of historic earthquake magnitudes in Hawaiʻi, please watch: youtu.be/k4bUliVLoOYTo view an animation of earthquake activity throughout the Hawaiian Islands, please watch: youtu.be/7wQkJ3THyN0To view an animation of activity associated with the 2018 Kīlauea eruptions, please watch: youtu.be/Pc9hM08uscMThis animation uses data from the USGS's National Earthquake Information Center (NEIC): earthquake.usgs.gov/earthquakes/search
Earthquakes of the Hawaiian Islands: 1973 - 2018 PacificTWC 2019-04-20 | This animation shows earthquakes within the Hawaiian Islands in sequence as they occurred from January 1, 1973, through December 31, 2018. Prior to 2018 the animation proceeds at a speed of one year per second, but shifts into a “slow motion” rate of one month per second for 2018 to better show the extraordinary seismic activity associated with that year’s new eruptive activity on Kīlauea Volcano.The earthquake hypocenters first appear as flashes then remain as colored circles before shrinking with time so as not to obscure subsequent earthquakes. The initial size of the circle represents the earthquake magnitude while the color represents its depth within the earth. The animation concludes with a summary map showing all of the quakes used in this presentation.For consistency this animation only shows those earthquakes with magnitudes 3.0 or larger, as the NEIC earthquake catalog (link below) rarely includes smaller events in Hawaiʻi prior to 2006. Likewise, the animation begins in 1973 because that is when the NEIC catalog begins to have a enough of events in this region to be useful for showing a time-lapse sequence.This time period includes some noteworthy events:1973: Honomū, M6.11975: Kalapana, M7.7, also generated a tsunami that killed 2 people1983: Kaōʻiki, M6.71989: Puna, M6.51996: Lōʻihi Seamount earthquake swarm coincident with summit collapse and crater formation2006: Kīholo Bay, M6.72006: Māhukona, M6.12018: Kalapana, M6.9, plus numerous foreshocks, aftershocks, and volcanic activityInstead of plate tectonics, three principal mechanisms cause seismic activity within the Hawaiian Islands. First, movement of magma within volcanoes and other volcanic phenomena (such as explosions) can cause ground shaking. Second, motion along faults within the volcanoes and at the boundary between the volcanoes and the old ocean floor they sit on can generate earthquakes, including the largest ones recorded in Hawaiʻi. And third, the weight of these enormous volcanoes bends the lithosphere (oceanic crust + brittle upper mantle) and sometimes it will break, causing earthquakes. In this animation events recorded within the volcano tend to be shallower and will have “warmer” (red, orange, yellow) colors, while those within the lithosphere tend to be deeper and have “cooler” (blue to violet) colors. For a fuller explanation of the origin of earthquakes in Hawaiʻi please watch this video: youtu.be/H0bnaV35SnoFor a comparison of historic earthquake magnitudes in Hawaiʻi, please watch: youtu.be/k4bUliVLoOYTo see an animation of the 1975 Kalapana tsunami , please watch: youtu.be/0Ho0BzF2eCYTo view details of Big Island earthquake activity, please watch: youtu.be/mHCIxd3et5kTo view an animation of activity associated with the 2018 Kīlauea eruptions, please watch: youtu.be/Pc9hM08uscMThis animation uses data from the USGS's National Earthquake Information Center (NEIC): earthquake.usgs.gov/earthquakes/search
Earthquakes of the 20th Century PacificTWC 2018-12-09 | This animation shows every recorded earthquake in sequence as they occurred from January 1, 1901, through December 31, 2000, at a rate of 1 year per second. The earthquake hypocenters first appear as flashes then remain as colored circles before shrinking with time so as not to obscure subsequent earthquakes. The size of the circle represents the earthquake magnitude while the color represents its depth within the earth. At the end of the animation it will first show all quakes in this 100-year period. Next, it will show only those earthquakes greater than magnitude 6.5, the smallest earthquake size known to make a tsunami. It will then show only those earthquakes with magnitudes of 8.0 or larger, the “great” earthquakes most likely to pose a tsunami threat when they occur under the ocean or near a coastline and when they are shallow within the earth (less than 100 km or 60 mi. deep). The animation concludes by showing the plate boundary faults responsible for the majority of all of these earthquakes.The era of modern earthquake seismology—the scientific study of earthquakes—began in the 20th Century with the invention of the seismometer and its deployment in instrument networks to record and measure earthquakes as they occur. Therefore, when the animation begins only the largest earthquakes appear as they were the only ones that could be detected at great distances with the few available instruments available at the time. But as time progresses, more and more seismometers were deployed and smaller and smaller earthquakes could be recorded. For example, note how in the 1930’s many small earthquakes suddenly seem to appear in California, but this illusion results from the installation of more and more instruments in that region. Likewise, there appears to be a jump in the number of earthquakes globally in the 1970’s when seismology took another leap forward with advances in telecommunications and signal processing with digital computers, a trend that continues today.20th Century seismology revealed the global geographic distribution of earthquakes and helped to solidify the Theory of Plate Tectonics. Notice how earthquake epicenters do not occur randomly in space but form patterns over the earth’s surface, revealing the boundaries between tectonic plates as shown toward the end of this animation. This time period also includes some remarkable events, including those that generated devastating tsunamis:8.8 — Ecuador — 31January 19068.4 — Kamchatka, Russia — 3 February 19238.4 — Sanriku, Japan — 2 March 19338.6 — Unimak Island, Aleutian Islands — 1 April 19469.0 — Kamchatka, Russia — 4 November 19528.6 — Andreanof Islands, Aleutian Islands — 9 March 19579.5 — Valdivia, Chile — 22 May 19609.2 — Prince William Sound, Alaska — 28 March 19648.7 — Rat Islands, Aleutian Islands — 4 February 1965These earthquakes represent some of the largest ever recorded. Note how they all occur at a particular type of plate boundary, subduction zones where tectonic plates collide, so these are the regions where we expect future devastating tsunamis to be generated.NOAA Science on a Sphere version:sos.noaa.gov/datasets/earthquakes-of-the-20th-centuryEarthquake source used: NEIC Earthquake Catalogearthquake.usgs.gov/earthquakes/search
Tsunami Animation: Hawaii 1975 PacificTWC 2018-11-29 | Not all tsunamis in the Hawaiian Islands come from overseas. On the early morning of November 29, 1975, a 7.7 magnitude* earthquake struck the southeast coast of the Big Island of Hawaii and generated a tsunami as high as 48 ft. (14.6 m). A 26 ft. (7.9 m) high wave killed two campers at the Halape Campground in Hawaii Volcanoes National Park. The tsunami also damaged property elsewhere on the Island of Hawaii and smaller non-destructive waves traveled as far as Alaska, California, Japan, and Samoa. For more information about this earthquake please see http://hvo.wr.usgs.gov/earthquakes/destruct/1975Nov29Our animation shows how this tsunami may have propagated in the Hawaiian Islands, transitioning at its end first to an "energy map" showing the maximum wave heights over the 6-hour period that the animation covers, then finishing with calculated tsunami runup heights on land. Note how the waves wrap around the islands and reach Honolulu in about 45 minutes. The campers in Halape, however, had only a few minutes to react, illustrating the most dangerous aspect of locally generated tsunamis: that people nearest to the tsunami source (earthquake, landslide, etc.) cannot wait for a siren to signal danger. If you are on or near a coastline and feel shaking so strong you cannot stand up, or shaking that lasts for a minute or more, leave the area as soon as the shaking stops and go to ground at least 50 ft. (15 m) above sea level. In Hawaii walking inland for about 20 minutes will usually do it, but you can see Hawaii's tsunami evacuation zones in your phone book or on this NOAA website: http://tsunami.csc.noaa.gov/map.html*Nettles, M. and G. Ekström, "Long-Period Source Characteristics of the 1975 Kalapana, Hawaii, Earthquake," Bulletin of the Seismological Society of America, 2004
Earthquake Animation: Kīlauea Caldera - 1 April to 31 August 2018 PacificTWC 2018-09-22 | The NWS’s Pacific Tsunami Warning Center (PTWC) mitigates tsunami hazards in Hawai‘i produced by large, distant earthquakes throughout the Pacific Ocean, but PTWC also issues warnings for tsunamis generated by earthquakes within the State of Hawai‘i itself. The last such dangerous tsunami was generated by a 7.7 magnitude earthquake on the Big Island of Hawai‘i in 1975. Small earthquakes generated by volcanic activity are far more common, and typically have a magnitude less than 3.0 and occur a few times a day. That rate changed on the afternoon of April 30, 2018, when an earthquake “swarm” began within Kīlauea Volcano such that earthquakes began to occur far more frequently, about 100 per day.This animation is shows the earthquake activity and topographic changes of Kīlauea's summit area, Kīlauea Caldera, by transitioning the map to include recent high-resolution LIDAR data in the underlying topographic relief image. It begins a month earlier on April 1 to start with a more typical earthquake pattern and proceeds forward in time at a rate of one day per second. White circles indicate the location of earthquakes as they occur with their sizes proportional to their magnitudes. Lava began to erupt from Kīlauea’s Lower East Rift Zone on May 3 (see the “first 100 days” link below) and the level of the lava lake within Halema‘uma‘u Crater began to drop the next day. By May 15 the lava lake had dropped hundreds of feet below the crater floor before producing steam-driven explosions when the molten rock interacted with ground water. Some of these explosions were strong enough to register as earthquakes with magnitudes greater than 5.0 and send ash clouds to 30,000 ft. above sea level. By the end of May, however, these explosions changed their character such that they no longer produced large steam-driven ash clouds. The walls of Halema‘uma‘u had begun to collapse, thus widening it and deepening it as magma continued to drain from the summit to feed the flank eruption. These “collapse explosions” seemed to release trapped volcanic gas rather than groundwater steam and yielded only small ash clouds, though they still released explosive energy greater than magnitude 5.0 earthquakes and occurred about once per day (see the “collapse explosion” link below for a full description). No explosions have occurred since August 2 (as of Sept 22, 2018).This animation includes charts showing some statistics about the earthquake activity. The top graph shows the earthquake magnitudes as they occur. The bottom graph shows the number of earthquakes per hour within the map area. With the subsidence of Kīlauea Caldera and the collapse of Halema‘uma‘u the number of earthquakes dramatically increased to more than 40 per hour by June 15 and continued until August 4 when they suddenly returned to normal background levels, coinciding with the pause in the eruption of lava from the Lower East Rift Zone in Puna.Though PTWC monitors all earthquakes in Hawai‘i, including this volcanic activity, the primary responsibility for mitigating volcanic hazards in the State of Hawai‘i rests with the USGS’s Hawaiian Volcano Observatory who publishes updates daily and advises local emergency managers.-----An animation of activity associated with the 2018 Kīlauea eruptions, including lava flows:youtu.be/Pc9hM08uscMExplanation of “collapse explosions” within the caldera:volcanoes.usgs.gov/observatories/hvo/hvo_volcano_watch.html?vwid=1371Video of "collapse explosion" earthquake:volcanoes.usgs.gov/vsc/movies/movie_174018.htmlThe Hawaiian Volcano Observatory's eruption information page:volcanoes.usgs.gov/observatories/hvo/activity_2018.htmlFor general information about explosive eruptions in Hawai‘i:pubs.usgs.gov/fs/fs132-98For general information about earthquake hazards in Hawai‘i:volcanoes.usgs.gov/observatories/hvo/hazards_earthquakes.htmlOrigin of earthquakes in the Hawaiian Islands:youtu.be/H0bnaV35SnoComparison of historic earthquakes in Hawai‘i by magnitude:youtu.be/k4bUliVLoOY1975 Hawai‘i Island tsunami:youtu.be/0Ho0BzF2eCYEarthquake data source:earthquake.usgs.gov/earthquakes/searchLIDAR data source:opentopography.org/news/2018-kilauea-volcano-datasets-available-download
Context: a graphical comparison of earthquake energy release in Hawaiʻi PacificTWC 2018-05-29 | On May 4, 2018, the largest earthquake in 43 years struck Hawaiʻi with a moment magnitude of 6.9 in the Kalapana region of the Island of Hawaiʻi (the “Big Island”). This animation puts that earthquake in historic context by comparing its magnitude with those of other earthquakes that have struck these islands in the last 150 years. The moment magnitude number is proportional to an earthquake's total energy release such that each whole number increase in magnitude represents about a 32-fold increase in energy relase. For example, a M7 earthquake releases about 32 times as much energy as a M6 earthquake. Therefore in this animation the circle for a M7 earthquake has about 32 times the area of a M6 earthquake. Each circle is also labeled to show its magnitude, its location, and the year it happened. The animation reveals that three earthquakes are known to have been larger—that is, have released even more energy—than 2018 Kalapana earthquake. The animation concludes with a map showing where each of these earthquakes happened in Hawaiʻi.Global version:youtu.be/sTvtKUb-RsY----------Earthquake data sources:USGS/NEIC Searchable Earthquake catalogearthquake.usgs.gov/earthquakes/searchUSGS Professional Paper 1527: Seismicity of the United States, 1568-1989 (revised) by C.W. Stover and J.L. Coffman pubs.er.usgs.gov/publication/pp1527
Tsunami Forecast Model Animation: Aleutian Islands 1957 PacificTWC 2017-03-26 | At 4:22 am on Saturday, March 9, 1957 (9 March, 14:22 Z UTC) the second great earthquake in 11 years struck Alaska’s Aleutian Islands. This earthquake had the same magnitude of the earlier earthquake--8.6 on the moment magnitude scale (Johnson et al. 1994)--but was to the west of the 1946 earthquake, near the Andreanof Islands. As with the earlier event it also caused a dangerous tsunami that caused significant damage in the Aleutian Islands and in Hawaii and was observed as far away as Chile. The greatest wave heights were in Alaska’s Aleutian Islands, with waves nearly 23 m or 75 ft. high coming ashore on Unimak Island. The tsunami would reach Hawaii a little over four hours later, with the largest waves striking the island of Kauai at over 11 m or 38 ft. high and would cause $5.3 million in damage statewide ($46 million in 2017), including the destruction of more than 80 homes. Elsewhere around the Pacific Ocean the tsunami waves would reach heights of 6 m or 20 ft. in the Marquesas Islands (French Polynesia), 3 m or 10 ft. in Japan, 1.5 m or 5 ft. in American Samoa, and over 1 m or 3 ft. in Mexico and Chile. Unlike the earlier event, however, it did not kill any people thanks to effective tsunami alerts from to the Honolulu Observatory and the Seismic Sea Wave Warning System. These efforts, established in 1948, would later become the Pacific Tsunami Warning Center (PTWC) and Pacific Tsunami Warning System.Today, more than 60 years since this earthquake, PTWC will issue tsunami warnings in minutes after a major earthquake occurs, and will also forecast how large any resulting tsunami will be as it is still crossing the ocean. PTWC can also create an animation of a historical tsunami with the same tool that it uses to determine tsunami hazards in real time for any tsunami today: the Real-Time Forecasting of Tsunamis (RIFT) forecast model. The RIFT model takes earthquake information as input and calculates how the waves move through the world’s oceans, predicting their speed, wavelength, and amplitude. This animation shows these values through the simulated motion of the waves and as they travel through the Pacific Ocean one can also see the distance between successive wave crests (wavelength) as well as their height (amplitude) indicated by their color. More importantly, the model also shows what happens when these tsunami waves strike land, the very information that PTWC needs to issue tsunami hazard guidance for impacted coastlines. From the beginning the animation shows all coastlines covered by colored points. These are initially a blue color like the undisturbed ocean to indicate normal sea level, but as the tsunami waves reach them they will change color to represent the height of the waves coming ashore, and often these values are higher than they were in the deeper waters offshore. The color scheme is based on PTWC’s warning criteria, with blue-to-green representing no hazard (less than 30 cm or ~1 ft.), yellow-to-orange indicating low hazard with a stay-off-the-beach recommendation (30 to 100 cm or ~1 to 3 ft.), light red-to-bright red indicating significant hazard requiring evacuation (1 to 3 m or ~3 to 10 ft.), and dark red indicating a severe hazard possibly requiring a second-tier evacuation (greater than 3 m or ~10 ft.).Toward the end of this simulated 36 hours of activity the wave animation will transition to the “energy map” of a mathematical surface representing the maximum rise in sea-level on the open ocean caused by the tsunami, a pattern that indicates that the kinetic energy of the tsunami was not distributed evenly across the oceans but instead forms a highly directional “beam” such that the tsunami was far more severe in the middle of the “beam” of energy than on its sides. This pattern also generally correlates to the coastal impacts; note how those coastlines directly in the “beam” are hit by larger waves than those to either side of it.Earthquake source used:Johnson, J.M., Y. Tanioka, L.J. Ruff, K. Satake, H. Kanamori, and L.R. Sykes, The 1957 Great Aleutian Earthquake, PAGEOPH, 142, 3-28, 1994
Perspective: a graphical comparison of earthquake energy release PacificTWC 2016-12-29 | Tsunami warning center scientists usually measure an earthquake's "size" with the moment magnitude scale rather than the older but more famous Richter magnitude scale. The moment magnitude scale is better suited for measuring the "sizes" of very large earthquakes and its values are proportional to an earthquake's total energy release, making this measurement more useful for tsunami forecasting.Moment magnitude numbers scale such that that energy release increases by a factor of about 32 for each whole magnitude number. For example, magnitude 6 releases about 32 times as much energy as magnitude 5, magnitude 7 about 32 times as much as magnitude 6, and so on.This animation graphically compares the relative "sizes" of some 20th and 21st century earthquakes by their moment magnitudes. Each circle's area represents its relative energy release, and its label lists its moment magnitude, its location, and the year it happened.-----Los científicos del centro de alertas de tsunamis miden el "tamaño" de un terremoto utilizando la escala de magnitud de momento y no otras escalas más antiguas y famosas como la escala de magnitud de Richter. La escala de magnitud de momento es más adecuada para medir el tamaño de grandes terremotos, y sus valores son proporcionales a la cantidad de energía liberada, lo cual hace esta medida de magnitud más útil para el pronóstico de tsunamis.Los números en la escala de magnitud de momento escalan de manera que la cantidad de energía liberada se incrementa 32 veces por cada número entero de diferencia. Por ejemplo, un evento con magnitud 6.0 libera cerca de 32 veces más energía que uno de 5.0, y uno de magnitud 7.0 libera 32 veces más energía que uno con magnitud 6.0, etcétera.Esta animación compara gráficamente el tamaño relativo de algunos terremotos ocurridos durante los siglos XX y XXI en términos de su magnitud de momento. El área de cada círculo representa de forma comparativa la cantidad de energía liberada, y su etiqueta lista su magnitud de momento, su localización, y su año de ocurrencia.-----NOAA Science on a Sphere version:http://sos.noaa.gov/Datasets/dataset.php?id=644
Tsunami Forecast Model Animation: Sumatra 2004 PacificTWC 2016-12-22 | The magnitude 9.1 Great Sumatra-Andaman Earthquake of December 26, 2004, spawned the deadliest tsunami in history, killing more than 230,000 people in 14 countries around the Indian Ocean. More than half of those killed had lived in Acheh Province, Sumatra, where the tsunami rose as high as 30 m (100 ft.) and traveled more than 4 km (2.5 mi.) inland in this low-lying region.This earthquake began at its epicenter near northern Sumatra and moved the earth's crust an average of 15 m (50 ft.) as it ruptured northward for at least 1200 km (750 mi.) almost to the coast of Myanmar (Burma) over an 8-minute period. This distance is at least 200 km (125 mi.) longer than the length of fault that moved during the largest earthquake ever recorded, the magnitude 9.5 Great Chile Earthquake of 1960.This animation shows why this south-to-north rupture is important for understanding the behavior of this tsunami, and why such "progressive" rupture needs to be considered for future tsunami forecasting. If the earthquake had moved the fault along its entire length all-at-once it would have sent the largest tsunami waves perpendicular to the fault and so they would have passed south of Sri Lanka. The earthquake motion, however, started in the south and moved northward along the fault so the tsunami began radiating from near Sumatra before it could be generated near Myanmar, thus causing the largest tsunami waves to strike Sri Lanka and Somalia directly, consistent with the tsunami waves actually observed in those countries.The Pacific Tsunami Warning Center (PTWC) can create an animation of a historical tsunami like this one using the same tool that it uses to determine tsunami hazards in real time for any tsunami today: the Real-Time Forecasting of Tsunamis (RIFT) forecast model. The RIFT model takes earthquake information as input and calculates how the waves move through the world’s oceans, predicting their speed, wavelength, and amplitude. This animation shows these values through the simulated motion of the waves and as they travel through the world’s oceans one can also see the distance between successive wave crests (wavelength) as well as their height (amplitude) indicated by their color. More importantly, the model also shows what happens when these tsunami waves strike land, the very information that PTWC needs to issue tsunami hazard guidance for impacted coastlines. From the beginning the animation shows all coastlines covered by colored points. These are initially a blue color like the undisturbed ocean to indicate normal sea level, but as the tsunami waves reach them they will change color to represent the height of the waves coming ashore, and often these values are higher than they were in the deeper waters offshore. The color scheme is based on PTWC’s warning criteria, with blue-to-green representing no hazard (less than 30 cm or ~1 ft.), yellow-to-orange indicating low hazard with a stay-off-the-beach recommendation (30 to 100 cm or ~1 to 3 ft.), light red-to-bright red indicating significant hazard requiring evacuation (1 to 3 m or ~3 to 10 ft.), and dark red indicating a severe hazard possibly requiring a second-tier evacuation (greater than 3 m or ~10 ft.).Toward the end of this simulated 24 hours of activity the wave animation will transition to the “energy map” of a mathematical surface representing the maximum rise in sea-level on the open ocean caused by the tsunami, a pattern that indicates that the kinetic energy of the tsunami was not distributed evenly across the oceans but instead forms a highly directional “beam” such that the tsunami was far more severe in the middle of the “beam” of energy than on its sides. This pattern also generally correlates to the coastal impacts; note how those coastlines directly in the “beam” are hit by larger waves than those to either side of it.Earthquake source used:Chlieh, M., Avouac, J., Hjorleifsdottir, V., Song, T.A., Ji, C., Sieh, K., Sladen, A., Hebert, H., Prawirodirdjo, L., Bock., Y., & Galetzka, J. (2007) "Coseismic Slip and Afterslip of the Great Mw 9.15 Sumatra--Andaman Earthquake of 2004." Bulletin of the Seismological Society of America, 97 (1A), S152--S173, DOI: 10.1785/0120050631NOAA Science-on-a-Sphere version:http://sos.noaa.gov/Datasets/dataset.php?id=642
Earthquakes of the First 15 Years of the 21st Century PacificTWC 2016-12-02 | This animation shows every recorded earthquake in sequence as they occurred from January 1, 2001, through December 31, 2015, at a rate of 30 days per second. The earthquake hypocenters first appear as flashes then remain as colored circles before shrinking with time so as not to obscure subsequent earthquakes. The size of the circle represents the earthquake magnitude while the color represents its depth within the earth. At the end of the animation it will first show all quakes in this 15-year period. Next, it will show only those earthquakes greater than magnitude 6.5, the smallest earthquake size known to make a tsunami. Finally it will only show those earthquakes with magnitudes of magnitude 8.0 or larger, the “great” earthquakes most likely to pose a tsunami threat when they occur under the ocean or near a coastline and when they are shallow within the earth (less than 100 km or 60 mi. deep). This time period includes some remarkable events. Several large earthquakes caused devastating tsunamis, including 9.1 magnitude in Sumatra (26 December 2004), 8.1 magnitude in Samoa (29 September 2009), 8.8 magnitude in Chile (27 February 2010), and 9.0 magnitude off of Japan (11 March 2011). Like most earthquakes these events occurred at plate boundaries, and truly large events like these tend to occur at subduction zones where tectonic plates collide. Other, much smaller earthquakes also occur away from plate boundaries such as those related to volcanic activity in Hawaii or those related to wastewater injection wells in Oklahoma.NOAA Science on a Sphere version:http://sos.noaa.gov/Datasets/dataset.php?id=643Earthquake source used: NEIC Earthquake Cataloghttp://earthquake.usgs.gov/earthquakes/search
Tsunami Forecast Model Animation: Lisbon 1755 PacificTWC 2016-11-05 | On the morning of November 1, 1755, a great earthquake shook Portugal's capital city of Lisbon as worshipers filled churches and cathedrals for the All Saints' Day Mass. In seconds it left the city in ruins and in minutes those ruins were on fire. The earthquake probably killed about 30,000 people, though some estimates double that figure. Many of the survivors fled to the wharves and keys of Lisbon's port, but they would find no safety there. The first tsunami wave surged up the Tagus estuary about an hour after the earthquake, reached a maximum runup of 12 meters (40 feet), and killed another 1000 people. At least two more tsunami waves surged into the city, completing the earthquake's destruction.At Portugal's coastal city of Lagos the tsunami was even larger, perhaps 30 m (100 ft). It went on to damage the ports of Cadiz in Spain, then Safi and Agadir in Morocco. The tsunami also spread north: it caused minor damage at Brest in Brittany, some flooding in England in the Scilly Islands and in Cornwall, and extensively flooded of the low-lying areas of the city of Cork, Ireland. As it spread out across the Atlantic, the tsunami first reached Madeira, where observers recorded a runup of 4 m (13 ft), then the Canary Islands, the Azores, and eventually the West Indies, where observers recorded runups of about a 1 m (3 ft) in Barbados, Martinique, Guadeloupe, and Antigua (and questionable reports of large runup in the Virgin Islands). Though the tsunami must have hit Colonial America, no one recorded it there, though it was observed in Newfoundland.The Pacific Tsunami Warning Center (PTWC) can create an animation of a historical tsunami like this one using the same tool that it uses to determine tsunami hazards in real time for any tsunami today: the Real-Time Forecasting of Tsunamis (RIFT) forecast model. The RIFT model takes earthquake information as input and calculates how the waves move through the world’s oceans, predicting their speed, wavelength, and amplitude. This animation shows these values through the simulated motion of the waves and as they travel through the world’s oceans one can also see the distance between successive wave crests (wavelength) as well as their height (half-amplitude) indicated by their color. More importantly, the model also shows what happens when these tsunami waves strike land, the very information that PTWC needs to issue tsunami hazard guidance for impacted coastlines. From the beginning the animation shows all coastlines covered by colored points. These are initially a blue color like the undisturbed ocean to indicate normal sea level, but as the tsunami waves reach them they will change color to represent the height of the waves coming ashore, and often these values are higher than they were in the deeper waters offshore. The color scheme is based on PTWC’s warning criteria, with blue-to-green representing no hazard (less than 30 cm or ~1 ft.), yellow-to-orange indicating low hazard with a stay-off-the-beach recommendation (30 to 100 cm or ~1 to 3 ft.), light red-to-bright red indicating significant hazard requiring evacuation (1 to 3 m or ~3 to 10 ft.), and dark red indicating a severe hazard possibly requiring a second-tier evacuation (greater than 3 m or ~10 ft.).Our model of this tsunami assumes its source was a magnitude 8.5 earthquake on the Horseshoe Fault off of Cape Finisterre. Baptista, et al. (2011) explain how this fault matches the tsunami observations better than the several other proposed sources for the Great Lisbon EarthquakeToward the end of this simulated 24 hours of activity the wave animation will transition to the “energy map” of a mathematical surface representing the maximum rise in sea-level on the open ocean caused by the tsunami, a pattern that indicates that the kinetic energy of the tsunami was not distributed evenly across the oceans but instead forms a highly directional “beam” such that the tsunami was far more severe in the middle of the “beam” of energy than on its sides. This pattern also generally correlates to the coastal impacts; note how those coastlines directly in the “beam” are hit by larger waves than those to either side of it.Earthquake source used:Baptista, M.A., Miranda, J.M., Omira, R., & Antunes, C. (2011). "Potential inundation of Lisbon downtown by a 1755-like tsunami." Natural Hazards and Earth System Science, 11(12), 3319--3326.NOAA Science-on-a-Sphere Version: http://sos.noaa.gov/Datasets/dataset.php?id=639
Tsunami Forecast Model Animation: Samoa 2009 PacificTWC 2016-09-23 | At 6:48 on the morning of September 29, 2009 (17:48 UTC), an 8.1 moment magnitude earthquake struck near the Samoan Islands in the southwest Pacific Ocean. The Pacific Tsunami Warning Center (PTWC) quickly determined that the large magnitude of this earthquake, its location under the sea floor, its relatively shallow depth within the earth, and a history of tsunami-causing earthquakes in the region meant that it could have moved the seafloor and thus posed a significant tsunami risk. PTWC issued its first tsunami warning several minutes later for Samoa, American Samoa, Tonga, and other nearby island groups. The earthquake did in fact cause a dangerous tsunami, and over the following hours PTWC tracked it through the Pacific Ocean and updated its alerts with measured tsunami wave heights and recommended that additional areas consider coastal evacuation. PTWC canceled all tsunami alerts about four hours after the earthquake. Destructive waves only struck islands near the earthquake’s epicenter, where casualties were significant. The tsunami reached over 12 m or nearly 40 ft. high in Samoa, killing 149 people there. In nearby American Samoa the waves were even higher at over 17 m or 55 ft, killing 34, and topped 22 m or 72 ft in Tonga, killing 9 more people there. Smaller waves traveled throughout the Pacific Ocean but caused no more deaths or damage.The Pacific Tsunami Warning Center (PTWC) can create an animation of a historical tsunami like this one with the same tool that it uses to determine tsunami hazards in real time for any tsunami today: the Real-Time Forecasting of Tsunamis (RIFT) forecast model. The RIFT model takes earthquake information as input and calculates how the waves move through the world’s oceans, predicting their speed, wavelength, and amplitude. This animation shows these values through the simulated motion of the waves and as they travel through the world’s oceans one can also see the distance between successive wave crests (wavelength) as well as their height (half-amplitude) indicated by their color. More importantly, the model also shows what happens when these tsunami waves strike land, the very information that PTWC needs to issue tsunami hazard guidance for impacted coastlines. From the beginning the animation shows all coastlines covered by colored points. These are initially a blue color like the undisturbed ocean to indicate normal sea level, but as the tsunami waves reach them they will change color to represent the height of the waves coming ashore, and often these values are higher than they were in the deeper waters offshore. The color scheme is based on PTWC’s warning criteria, with blue-to-green representing no hazard (less than 30 cm or ~1 ft.), yellow-to-orange indicating low hazard with a stay-off-the-beach recommendation (30 to 100 cm or ~1 to 3 ft.), light red-to-bright red indicating significant hazard requiring evacuation (1 to 3 m or ~3 to 10 ft.), and dark red indicating a severe hazard possibly requiring a second-tier evacuation (greater than 3 m or ~10 ft.).Toward the end of this simulated 24 hours of activity the wave animation will transition to the “energy map” of a mathematical surface representing the maximum rise in sea-level on the open ocean caused by the tsunami, a pattern that indicates that the kinetic energy of the tsunami was not distributed evenly across the oceans but instead forms a highly directional “beam” such that the tsunami was far more severe in the middle of the “beam” of energy than on its sides. This pattern also generally correlates to the coastal impacts; note how those coastlines directly in the “beam” are hit by larger waves than those to either side of it.Earthquake source used: USGS Finite Fault Model, see:http://earthquake.usgs.gov/earthquakes/eventpage/usp000h1ys#finite-fault
Tsunami Forecast Model Animation: Chile 1960 PacificTWC 2016-05-24 | On May 22, 1960, at 3:11 pm (19:11 UTC) the largest earthquake ever recorded by instruments struck southern Chile with a magnitude we now know to be at least 9.5. This earthquake generated a tsunami that traveled through every ocean on earth, though large, dangerous waves only impacted the coastlines around the Pacific Ocean. Chile suffered the greatest impact, with tsunami waves reaching as high as 25 m or 82 ft., killing an estimated 2000 people there. Outside of Chile the tsunami was worst on the opposite side of the planet in Japan, where waves reached as high as 6.3 m or over 20 ft and killed 139 people. In between and halfway across the Pacific Ocean Hawaii suffered the second-worst tsunami in its recorded history--only the Aleutian Islands tsunami of 1946 was worse. It killed 61 people in the town of Hilo with waves reaching as high as 10.7 m or about 35 ft. and all Hawaiian Islands experienced waves well over 1 m or 3 ft. The Philippines also lost 21 people to waves recorded as high as 1.5 m or nearly 5 ft, and two more people died in California from waves reaching 2.2 m or over 7 ft. high. Elsewhere around the Pacific Ocean tsunami waves reached as high as 12.2 m or 40 ft at Pitcairn Island (U.K), 7.0 m or 23 ft. in Russia (Kamchatka), 5.0 m or over 16 ft. in New Zealand, 4.9 m or 16 ft. in (Western) Samoa, 2.4 m or about 8 ft. in French Polynesia, 2.1 m or 7 ft. in Canada, 1.8 m or about 6 ft. in Papua New Guinea, and 1.2 m or about 4 ft. in Mexico. In the United States and it territories 2.4 m or about 8 ft. in American Samoa, 2.3 m or 7.5 ft. in Alaska, and 1.8 m or about 6 ft. in Oregon.A global tsunami warning system did not exist in 1960 and the Honolulu Magnetic and Seismic Observatory, which would later become the Pacific Tsunami Warning Center (PTWC), did issue tsunami warnings for this earthquake to the State of Hawaii many hours in advance of its arrival (it would take almost 15 hours for the first wave to reach Hawaii). As a result of this tsunami the United Nations would set up the Pacific Tsunami Warning System (PTWS) in 1965 with the Honolulu Observatory as its headquarters.Today, more than 50 years since the Great Chile Earthquake and the establishment of the PTWS, the PTWC will issue tsunami warnings in minutes, not hours, after a major earthquake occurs, and will forecast how large any resulting tsunami will be as it is still crossing the ocean. The PTWC can also create an animation of a historical tsunami with the same tool that it uses to determine tsunami hazards in real time for any tsunami today: the Real-Time Forecasting of Tsunamis (RIFT) forecast model. The RIFT model takes earthquake information as input and calculates how the waves move through the world’s oceans, predicting their speed, wavelength, and amplitude. This animation shows these values through the simulated motion of the waves and as they travel through the world’s oceans one can also see the distance between successive wave crests (wavelength) as well as their height (half-amplitude) indicated by their color. More importantly, the model also shows what happens when these tsunami waves strike land, the very information that the PTWC needs to issue tsunami hazard guidance for impacted coastlines. From the beginning the animation shows all coastlines covered by colored points. These are initially a blue color like the undisturbed ocean to indicate normal sea level, but as the tsunami waves reach them they will change color to represent the height of the waves coming ashore, and often these values are higher than they were in the deeper waters offshore. The color scheme is based on the PTWC’s warning criteria, with blue-to-green representing no hazard (less than 30 cm or ~1 ft.), yellow-to-orange indicating low hazard with a stay-off-the-beach recommendation (30 to 100 cm or ~1 to 3 ft.), light red-to-bright red indicating significant hazard requiring evacuation (1 to 3 m or ~3 to 10 ft.), and dark red indicating a severe hazard possibly requiring a second-tier evacuation (greater than 3 m or ~10 ft.).Toward the end of this simulated 36 hours of activity the wave animation will transition to the “energy map” of a mathematical surface representing the maximum rise in sea-level on the open ocean caused by the tsunami, a pattern that indicates that the kinetic energy of the tsunami was not distributed evenly across the oceans but instead forms a highly directional “beam” such that the tsunami was far more severe in the middle of the “beam” of energy than on its sides. This pattern also generally correlates to the coastal impacts; note how those coastlines directly in the “beam” are hit by larger waves than those to either side of it.----------Earthquake source used:Fujii, Y. and K. Satake, Slip Distribution and Seismic Moment of the 2010 and 1960 Chilean Earthquakes Inferred from Tsunami Waveforms and Coastal Geodetic Data, Pure and Applied Geophysics, 170, 1493-1509, 2012
Tsunami Forecast Model Animation: Aleutian Islands 1946 PacificTWC 2016-03-31 | On April 1, 1946 at 4:28 am (12:28 UTC), an 8.6 moment magnitude earthquake struck off the coast of Unimak Island in Alaska’s Aleutian Islands, generating a tsunami that caused the greatest damage and number of deaths in Hawaii’s history, leading to the creation of the United States’ first tsunami warning system. As is typical for dangerous tsunamis the greatest wave heights were nearest the epicenter. The waves reached as high as 42 m or about 138 ft. on Unimak Island and destroyed its lighthouse and killed the five people there. Elsewhere this tsunami caused the greatest damage and number of deaths on inhabited Pacific islands. In Hawaii the waves reached about 17 m or 55 ft. high and killed 158 people, most in the town of Hilo, while in the Marquesas Islands in French Polynesia the waves reached even higher to 20 m or 65 ft but killed only two people. Chile’s Easter Island also got nearly 9 m or 28 ft.while its Juan Fernandez Islands got nearly 3 m or 9 ft. high waves. Pitcairn Island also had 5 m or 16 ft. high waves, New Zealand had over 2 m or 8 ft. high waves, and Samoa had over 1 m or about 4 ft. high waves. In North America the highest waves were in California at over 2 m or over 8 ft. and killed one person there and in South America it killed one more person in Peru.A tsunami warning system did not exist in 1946 and no one had any warning of the approaching dangerous waves. In response to this event the United States government set up its first tsunami warning operation at the Honolulu Magnetic and Seismic Observatory in 1948 to mitigate tsunami hazards in Hawaii. This facility would later be renamed the Pacific Tsunami Warning Center (PTWC) and expand its mission to include the rest of the Pacific Ocean and the Caribbean Sea.Today, 70 years since the Unimak Island Earthquake, PTWC will issue tsunami warnings in minutes after a major earthquake occurs and will also forecast how large any resulting tsunami will be as it is still crossing the ocean. PTWC can also create an animation of a historical tsunami with the same tool that it uses to determine tsunami hazards in real time for any tsunami today: the Real-Time Forecasting of Tsunamis (RIFT) forecast model. The RIFT model takes earthquake information as input and calculates how the waves move through the world’s oceans, predicting their speed, wavelength, and amplitude. This animation shows these values through the simulated motion of the waves and as they travel through the world’s oceans one can also see the distance between successive wave crests (wavelength) as well as their height (half-amplitude) indicated by their color. More importantly, the model also shows what happens when these tsunami waves strike land, the very information that PTWC needs to issue tsunami hazard guidance for impacted coastlines. From the beginning the animation shows all coastlines covered by colored points. These are initially a blue color like the undisturbed ocean to indicate normal sea level, but as the tsunami waves reach them they will change color to represent the height of the waves coming ashore, and often these values are higher than they were in the deeper waters offshore. The color scheme is based on PTWC’s warning criteria, with blue-to-green representing no hazard (less than 30 cm or ~1 ft.), yellow-to-orange indicating low hazard with a stay-off-the-beach recommendation (30 to 100 cm or ~1 to 3 ft.), light red-to-bright red indicating significant hazard requiring evacuation (1 to 3 m or ~3 to 10 ft.), and dark red indicating a severe hazard possibly requiring a second-tier evacuation (greater than 3 m or ~10 ft.).Toward the end of this simulated 36 hours of activity the wave animation will transition to the “energy map” of a mathematical surface representing the maximum rise in sea-level on the open ocean caused by the tsunami, a pattern that indicates that the kinetic energy of the tsunami was not distributed evenly across the oceans but instead forms a highly directional “beam” such that the tsunami was far more severe in the middle of the “beam” of energy than on its sides. This pattern also generally correlates to the coastal impacts; note how those coastlines directly in the “beam” are hit by larger waves than those to either side of it.The tsunami evacuation zones for Hawaii and Guam are available at http://tsunami.coast.noaa.gov. NOAA Science on a Sphere version available at:http://sos.noaa.gov/Datasets/dataset.php?id=606----------Earthquake source used: Lopez, Alberto M., and Emile A. Okal. A seismological reassessment of the source of the 1946 Aleutian 'tsunami' earthquake. Geophysical Journal International, vol. 165, p. 835–849. (http://gji.oxfordjournals.org/content/165/3/835)
Tsunami Forecast Model Animation: Alaska 1964 PacificTWC 2016-03-23 | At 5:36 pm on Friday, March 27, 1964 (28 March, 03:36Z UTC) the largest earthquake ever measured in North America, and the second-largest recorded anywhere, struck 40 miles west of Valdez, Alaska in Prince William Sound with a moment magnitude we now know to be 9.2. Almost an hour and a half later the Honolulu Magnetic and Seismic Observatory (later renamed the Pacific Tsunami Warning Center, or PTWC) was able to issue its first “tidal wave advisory” that noted that a tsunami was possible and that it could arrive in the Hawaiian Islands five hours later. Upon learning of a tsunami observation in Kodiak Island, Alaska, an hour and a half later the Honolulu Observatory issued a formal “tidal wave/seismic sea-wave warning” cautioning that damage was possible in Hawaii and throughout the Pacific Ocean but that it was not possible to predict the intensity of the tsunami. The earthquake did in fact generate a tsunami that killed 124 people (106 in Alaska, 13 in California, and 5 in Oregon) and caused about $2.3 billion (2016 dollars) in property loss all along the Pacific coast of North America from Alaska to southern California and in Hawaii. The greatest wave heights were in Alaska at over 67 m or 220 ft. and waves almost 10 m or 32 ft high struck British Columbia, Canada. In the “lower 48” waves as high as 4.5 m or 15 ft. struck Washington, as high as 3.7 m or 12 ft. struck Oregon, and as high as 4.8 m or over 15 ft. struck California. Waves of similar size struck Hawaii at nearly 5 m or over 16 ft. high. Waves over 1 m or 3 ft. high also struck Mexico, Chile, and even New Zealand.As part of its response to this event the United States government created a second tsunami warning facility in 1967 at the Palmer Observatory, Alaska--now called the National Tsunami Warning Center (NTWC, http://ntwc.arh.noaa.gov )--to help mitigate future tsunami threats to Alaska, Canada, and the U.S. Mainland.Today, more than 50 years since the Great Alaska Earthquake, PTWC and NTWC issue tsunami warnings in minutes, not hours, after a major earthquake occurs, and will also forecast how large any resulting tsunami will be as it is still crossing the ocean. PTWC can also create an animation of a historical tsunami with the same tool that it uses to determine tsunami hazards in real time for any tsunami today: the Real-Time Forecasting of Tsunamis (RIFT) forecast model. The RIFT model takes earthquake information as input and calculates how the waves move through the world’s oceans, predicting their speed, wavelength, and amplitude. This animation shows these values through the simulated motion of the waves and as they travel through the world’s oceans one can also see the distance between successive wave crests (wavelength) as well as their height (half-amplitude) indicated by their color. More importantly, the model also shows what happens when these tsunami waves strike land, the very information that PTWC needs to issue tsunami hazard guidance for impacted coastlines. From the beginning the animation shows all coastlines covered by colored points. These are initially a blue color like the undisturbed ocean to indicate normal sea level, but as the tsunami waves reach them they will change color to represent the height of the waves coming ashore, and often these values are higher than they were in the deeper waters offshore. The color scheme is based on PTWC’s warning criteria, with blue-to-green representing no hazard (less than 30 cm or ~1 ft.), yellow-to-orange indicating low hazard with a stay-off-the-beach recommendation (30 to 100 cm or ~1 to 3 ft.), light red-to-bright red indicating significant hazard requiring evacuation (1 to 3 m or ~3 to 10 ft.), and dark red indicating a severe hazard possibly requiring a second-tier evacuation (greater than 3 m or ~10 ft.).Toward the end of this simulated 24 hours of activity the wave animation will transition to the “energy map” of a mathematical surface representing the maximum rise in sea-level on the open ocean caused by the tsunami, a pattern that indicates that the kinetic energy of the tsunami was not distributed evenly across the oceans but instead forms a highly directional “beam” such that the tsunami was far more severe in the middle of the “beam” of energy than on its sides. This pattern also generally correlates to the coastal impacts; note how those coastlines directly in the “beam” are hit by larger waves than those to either side of it.----------Earthquake source used:Johnson, J. M., K. Satake, S. R. Holdahl, and J. Sauber, The 1964 Prince William Sound earthquake: Joint inversion of tsunami and geodetic data, J. Geophys. Res., 101, 523–532, 1996NOAA Science on s Sphere Version available at:http://sos.noaa.gov/Datasets/dataset.php?id=605
Tsunami Forecast Model Animation: Japan 2011 PacificTWC 2016-03-04 | At 14:46 on the afternoon of 11 March 2011 (05:46 UTC), a 9.0 moment magnitude earthquake struck near the coastline of Honshu, Japan. The Pacific Tsunami Warning Center (PTWC) quickly determined that the very large magnitude of this earthquake, its offshore location, its relatively shallow depth within the earth, and a history of megathrust earthquakes in the region meant that it likely moved the seafloor and thus posed a significant tsunami risk. As per international agreements Japanese authorities issued tsunami warnings for their own coastlines while PTWC began issuing warnings to other countries and territories in the western Pacific Ocean. The earthquake did in fact cause a tsunami, and over the following hours as PTWC learned more about the earthquake (confirming it was a megathrust and upgrading its magnitude) and its tsunami through forecast models and direct observation with DART sensors and coastal sea-level gauges PTWC would eventually issue tsunami warnings to the State of Hawaii and all remaining countries and territories participating the Pacific Tsunami Warning System, keeping warnings in some areas in effect for more than a day. PTWC’s sister office, the West Coast and Alaska Tsunami Warning Center (now known as the National Tsunami Warning Center), also issued tsunami warnings for Alaska and the Pacific coasts of the United States and Canada. The tsunami caused the greatest devastation and over 17,000 deaths in Japan, where waves reached over 40 m or 130 ft. high. Outside of Japan the tsunami also killed one person in Papua, Indonesia and rose to greater than 5 m or 16 ft. in the Galapagos Islands (Ecuador), greater than 2m or 6.5 ft. in Indonesia, Russia's Kuril Islands, and in Chile, and rose to greater than 1 m or 3 ft. in Costa Rica, the Marquesas Islands (French Polynesia), Mexico, Papua New Guinea, and Peru. In the United States the tsunami rose to more than 5 m or 16 ft. in Hawaii, more than 2 m or 6.5 ft in California and Oregon, and more than 1 m or 3 ft. in the U.S. island territories of Midway and Saipan (Northern Mariana Islands). The tsunami also killed one person in Crescent City, California.The Pacific Tsunami Warning Center (PTWC) can create an animation of a historical tsunami like this one using the same tool that it uses to determine tsunami hazards in real time for any tsunami today: the Real-Time Forecasting of Tsunamis (RIFT) forecast model. The RIFT model takes earthquake information as input and calculates how the waves move through the world’s oceans, predicting their speed, wavelength, and amplitude. This animation shows these values through the simulated motion of the waves and as they travel through the world’s oceans one can also see the distance between successive wave crests (wavelength) as well as their height (half-amplitude) indicated by their color. More importantly, the model also shows what happens when these tsunami waves strike land, the very information that PTWC needs to issue tsunami hazard guidance for impacted coastlines. From the beginning the animation shows all coastlines covered by colored points. These are initially a blue color like the undisturbed ocean to indicate normal sea level, but as the tsunami waves reach them they will change color to represent the height of the waves coming ashore, and often these values are higher than they were in the deeper waters offshore. The color scheme is based on PTWC’s warning criteria, with blue-to-green representing no hazard (less than 30 cm or ~1 ft.), yellow-to-orange indicating low hazard with a stay-off-the-beach recommendation (30 to 100 cm or ~1 to 3 ft.), light red-to-bright red indicating significant hazard requiring evacuation (1 to 3 m or ~3 to 10 ft.), and dark red indicating a severe hazard possibly requiring a second-tier evacuation (greater than 3 m or ~10 ft.).Toward the end of this simulated 36 hours of activity the wave animation will transition to the “energy map” of a mathematical surface representing the maximum rise in sea-level on the open ocean caused by the tsunami, a pattern that indicates that the kinetic energy of the tsunami was not distributed evenly across the oceans but instead forms a highly directional “beam” such that the tsunami was far more severe in the middle of the “beam” of energy than on its sides. This pattern also generally correlates to the coastal impacts; note how those coastlines directly in the “beam” are hit by larger waves than those to either side of it.-----Earthquake source used: USGS NEIC Finite Fault Modelhttp://earthquake.usgs.gov/earthquakes/eqinthenews/2011/usc0001xgp/finite_fault.phpFor a NOAA Science on a Sphere version of this animation, please see:http://sos.noaa.gov/Datasets/dataset.php?id=599
Tsunami Forecast Model Animation: Chile 2010 PacificTWC 2016-02-26 | At 3:34 on the morning of February 27, 2010 (06:34 UTC), an 8.8 moment magnitude earthquake struck near the coastline of central Chile. The Pacific Tsunami Warning Center (PTWC) quickly determined that the large magnitude of this earthquake, its location near the coastline, its relatively shallow depth within the earth, and a history of megathrust earthquakes in the region meant that it could have moved the seafloor and thus posed a significant tsunami risk and PTWC issued their first tsunami warning several minutes later for Chile and Peru. The earthquake did in fact cause a tsunami, and over the following hours as PTWC learned more about the earthquake (confirming it was a megathrust and upgrading its magnitude) and its tsunami through forecast models and direct observation with DART sensors and coastal sea-level gauges PTWC would eventually issue tsunami warnings to the State of Hawaii and all 43 countries and territories participating the Pacific Tsunami Warning System, keeping warnings in some areas in effect for more than a day. PTWC’s sister office, the West Coast and Alaska Tsunami Warning Center (now known as the National Tsunami Warning Center), also issued tsunami advisories for Alaska and the Pacific coasts of the United States and Canada. The tsunami caused the greatest devastation and 124 deaths in Chile, where waves reached as high as 29 m or 95 ft. on the mainland, over 18 m or 60 ft. in its Juan Fernandez Islands, and over 4 m or 14 ft. at Rapa Nui (Easter Island). Outside of Chile tsunami wave heights exceeded 1 m or 3 ft. in the Marquesas Islands (French Polynesia), New Zealand, the Kuril Islands (Russia), and in the United States in California and Hawaii, and caused minor damage in San Diego, California and in Japan.The Pacific Tsunami Warning Center (PTWC) can create an animation of a historical tsunami like this one using the same tool that it uses to determine tsunami hazards in real time for any tsunami today: the Real-Time Forecasting of Tsunamis (RIFT) forecast model. The RIFT model takes earthquake information as input and calculates how the waves move through the world’s oceans, predicting their speed, wavelength, and amplitude. This animation shows these values through the simulated motion of the waves and as they travel through the world’s oceans one can also see the distance between successive wave crests (wavelength) as well as their height (half-amplitude) indicated by their color. More importantly, the model also shows what happens when these tsunami waves strike land, the very information that PTWC needs to issue tsunami hazard guidance for impacted coastlines. From the beginning the animation shows all coastlines covered by colored points. These are initially a blue color like the undisturbed ocean to indicate normal sea level, but as the tsunami waves reach them they will change color to represent the height of the waves coming ashore, and often these values are higher than they were in the deeper waters offshore. The color scheme is based on PTWC’s warning criteria, with blue-to-green representing no hazard (less than 30 cm or ~1 ft.), yellow-to-orange indicating low hazard with a stay-off-the-beach recommendation (30 to 100 cm or ~1 to 3 ft.), light red-to-bright red indicating significant hazard requiring evacuation (1 to 3 m or ~3 to 10 ft.), and dark red indicating a severe hazard possibly requiring a second-tier evacuation (greater than 3 m or ~10 ft.).Toward the end of this simulated 30 hours of activity the wave animation will transition to the “energy map” of a mathematical surface representing the maximum rise in sea-level on the open ocean caused by the tsunami, a pattern that indicates that the kinetic energy of the tsunami was not distributed evenly across the oceans but instead forms a highly directional “beam” such that the tsunami was far more severe in the middle of the “beam” of energy than on its sides. This pattern also generally correlates to the coastal impacts; note how those coastlines directly in the “beam” are hit by larger waves than those to either side of it.-----Earthquake source used: USGS NEIC W-Phase CMThttp://earthquake.usgs.gov/earthquakes/eqinthenews/2010/us2010tfan/neic_tfan_wmt.phpFor a NOAA Science on a Sphere version of this animation, please see:http://sos.noaa.gov/Datasets/dataset.php?id=597
Tsunami Forecast Model Animation: Cascadia 1700 PacificTWC 2016-01-22 | Just before midnight on January 27, 1700 a tsunami struck the coasts of Japan without warning since no one in Japan felt the earthquake that must have caused it. Nearly 300 years later scientists and historians in Japan and the United States solved the mystery of what caused this “orphan tsunami” through careful analysis of historical records in Japan as well as oral histories of Native Americans, sediment deposits, and ghost forests of drowned trees in the Pacific Northwest of North America, a region also known as Cascadia. They learned that this geologically active region, the Cascadia Subduction Zone, not only hosts erupting volcanoes but also produces megathrust earthquakes capable of generating devastating, ocean-crossing tsunamis. By comparing the tree rings of dead trees with those still living they could tell when the last of these great earthquakes struck the region. The trees all died in the winter of 1699-1700 when the coasts of northern California, Oregon, and Washington suddenly dropped 1-2 m (3-6 ft.), flooding them with seawater. That much motion over such a large area requires a very large earthquake to explain it—perhaps as large as 9.2 magnitude, comparable to the Great Alaska Earthquake of 1964. Such an earthquake would have ruptured the earth along the entire length of the 1000 km (600 mi) -long fault of the Cascadia Subduction Zone and severe shaking could have lasted for 5 minutes or longer. Its tsunami would cross the Pacific Ocean and reach Japan in about 9 hours, so the earthquake must have occurred around 9 o’clock at night in Cascadia on January 26, 1700 (05:00 January 27 UTC).The Pacific Tsunami Warning Center (PTWC) can create an animation of a historical tsunami like this one using the same tool that it uses to determine tsunami hazards in real time for any tsunami today: the Real-Time Forecasting of Tsunamis (RIFT) forecast model. The RIFT model takes earthquake information as input and calculates how the waves move through the world’s oceans, predicting their speed, wavelength, and amplitude. This animation shows these values through the simulated motion of the waves and as they travel through the world’s oceans one can also see the distance between successive wave crests (wavelength) as well as their height (half-amplitude) indicated by their color. More importantly, the model also shows what happens when these tsunami waves strike land, the very information that PTWC needs to issue tsunami hazard guidance for impacted coastlines. From the beginning the animation shows all coastlines covered by colored points. These are initially a blue color like the undisturbed ocean to indicate normal sea level, but as the tsunami waves reach them they will change color to represent the height of the waves coming ashore, and often these values are higher than they were in the deeper waters offshore. The color scheme is based on PTWC’s warning criteria, with blue-to-green representing no hazard (less than 30 cm or ~1 ft.), yellow-to-orange indicating low hazard with a stay-off-the-beach recommendation (30 to 100 cm or ~1 to 3 ft.), light red-to-bright red indicating significant hazard requiring evacuation (1 to 3 m or ~3 to 10 ft.), and dark red indicating a severe hazard possibly requiring a second-tier evacuation (greater than 3 m or ~10 ft.).Toward the end of this simulated 24 hours of activity the wave animation will transition to the “energy map” of a mathematical surface representing the maximum rise in sea-level on the open ocean caused by the tsunami, a pattern that indicates that the kinetic energy of the tsunami was not distributed evenly across the oceans but instead forms a highly directional “beam” such that the tsunami was far more severe in the middle of the “beam” of energy than on its sides. This pattern also generally correlates to the coastal impacts; note how those coastlines directly in the “beam” are hit by larger waves than those to either side of it.The full report about the Orphan Tsunami of 1700 can be found here:pubs.er.usgs.gov/publication/pp1707For a NOAA Science on a Sphere version of this animation, please see:http://sos.noaa.gov/Datasets/dataset.php?id=590
Tsunami Animation: Valdivia, Chile, 1960 (rotating globe) PacificTWC 2015-05-19 | The largest earthquake ever recorded by instruments struck southern Chile on May 22, 1960. This 9.5 magnitude earthquake generated a tsunami that crossed the Pacific Ocean, killing as many as 2000 people in Chile and Peru, 61 people in Hilo, Hawaii, and 142 people in Japan as well as causing damage in the Marquesas Islands (Fr. Polynesia), Samoa, New Zealand, Australia, the Philippines, and in Alaska's Aleutian Islands.Our animation adapts the earthquake source of Fujii and Satake (2012) to show how this tsunami may have propagated in the Pacific Ocean. The animation ends with a transition to an "energy map" summarizing the changes in open-ocean sea level height predicted by our real-time tsunami forecast model (RIFT).To see how this tsunami compares with two recent tsunamis from Chile, please watch http://youtu.be/qoxTC3vIF1U(Mercator version: youtu.be/oeKewmAoBEM)
¡Alerta de tsunami! PacificTWC 2015-05-15 | Cuando un terremoto submarino ocurre cerca de la costa el mismo puede generar un maremoto destructivo que golpeará las costas cercanas en minutos, y que también viajará a lo largo y ancho del oceáno causando daños a miles the kilómetros de distancia, incluso 24 horas más tarde. Para alertar a las costas lejanas, sistemas de alertas internacionalmente coordinados, como el Sistema de Alertas y Mitigación de Tsunamis del Pacífico (PTWS), se han establecido para proveer a los diferentes países con información acerca del peligro de tsunamis.2015 marca el 50 aniversario de la fundación del PTWS. El sistema se estableció en 1965 en respuesta al terremoto con magnitud 9.5 de 1960 ocurrido en la vecindad de la región centro-Sur de Chile, el cual generó un tsunami que cruzó el Pacífico matando a cientos de personas en Hawaii, Japón, y Las Filipinas. El PTWS se ha edificado a lo largo de varias décadas gracias a la cooperación internacional y contribuciones de los países y organizaciones miembros en el marco del IOC de la UNESCO.Para mantener la atención en los daños causados por tsunamis, así como educar al público en como el PTWS trabaja para diseminar alertas para un tsunami entrante, el ITIC, en cooperación con Chile, ha producido un video educacional de 6 minutos de duración. El próposito del video consiste en fortalecer los conocimientos y el grado de confianza del público y las agencias miembro en las alertas de tsunamis como la via para salvar vidas y reducir las pérdidas materiales.Este video documenta la serie de alertas de maremoto para un terremoto con magnitud 9.5 en la vecindad de la región Norte de Chile a medida que el personal del Centro de Alertas de Tsunamis del Pacífico (PTWC) rápidamente analiza los datos sísmicos y del nivel del mar, pronostica las alturas de las olas del maremoto, y disemina sus evaluaciones hacia los Centros de Alerta de Tsunamis Nacionales a lo largo del Pacífico. Intercalados en el rápido ritmo del video aparecen viñetas destacando las alertas de tsunami y las respuestas de emergencia por parte de centros de alerta nacionales y comunidades, comenzando inmediatamente después del terremoto en Chile y Perú, después de recibir las alertas en Samoa y Hawaii, así como en Australia, Japón, Indonesia, y Las Filipinas.For an English version, please see:youtu.be/XlxhRs7bst4Pour une version française , s'il vous plaît visitez : youtu.be/m4O_nnVslBQ
Alerte aux tsunamis! PacificTWC 2015-05-15 | Quand un séisme sous-marin se produit près de la côte, il peut générer un tsunami destructeur qui pourrait affecter les côtes à proximité dans quelques minutes, et se rendra également à ravers l'océan causant des dommages à des milliers de kilomètres même 24 heures plus tard. Pour alerter les côtes lointaines, les systèmes d'alerte coordonnés au niveau international, tels que le système d'alerte aux tsunamis dans le Pacifique (PTWS), ont été mis en place pour fournir des différents paysavec des informations sur le danger des tsunamis.2015 marque le 50e anniversaire de la fondation de la PTWS. Le système a été créé en 1965 en réponse à un tremblement de terre de magnitude 9,5 arrivé en 1960 dans le environs de la région centre-sud du Chili qui a généré un tsunami qui a traversé le Pacifique tuant des centaines de personnes à Hawaï, au Japon et aux Philippines. Le PTWS a été construit au cours des décennies grâce à la coopération internationale et les contributions des pays et organisations membres du COI de l'UNESCO.Pour maintenir l'attention sur les dégâts causés par les tsunamis, et éduquer le public sur la façon dont le PTWS travaille pour diffuser esalertes à un tsunami entrant, ITIC, en coopération avec le Chili, a produit une vidéo éducative de 6 minutes. Le but de la vidéo est de renforcer les connaissances et le degré de confiance du public et les organismes membres dans les alertes au tsunami comme un moyen de sauver des vies et de réduire les pertes de biens.Cette vidéo documente la série des alertes aux tsunamis pour un tremblement de terre de magnitude 9.5 dans le voisinage de la région nord du Chili tandis que le personnel au Centre d'alerte des Tsunamis dans le Pacifique (PTWC) analyse rapidement les données sismiques et le niveau de la mer, pronostique la hauteur des vagues du tsunami, et dissémine ses évaluations à des centres nationaux d'alerte à travers le Pacifique. Mélangées dans cette vidéo rapide sont vignettes mettant en évidence les alerte aux tsunamis et les mesures d'urgence pris par les centres nationaux d'alerte aux tsunamis et des communautés, commençant immédiatement après le tremblement de terre au Chili et au Pérou, après avoir reçu des alertes à Samoa et Hawaï, ainsi que l'Australie, le Japon, l'Indonésie et les Philippines.For an English version, please see:youtu.be/XlxhRs7bst4Para una versión española , por favor visite:youtu.be/aXx4pnVvz8I
Tsunami Warning! PacificTWC 2015-05-15 | When a major undersea earthquake occurs near the coast, a destructive tsunami can result that will hit near-by coasts in minutes and also travel across entire oceans causing damage 1000’s of kilometers away and up to 24 hours later. To alert far-away coasts, internationally coordinated tsunami early warning systems, such as the Pacific Tsunami Warning and Mitigation System (PTWS), have been established to quickly provide tsunami threat information to countries.2015 marks the 50th year of the PTWS. The System was established in 1965 in response to the 1960 M9.5 earthquake off South-central Chile that generated a tsunami which crossed the Pacific killing hundreds in Hawaii, Japan, and the Philippines. The PTWS has been built up over the decades through international cooperation and the contributions of countries and organizations under the UNESCO IOC framework.To sustain awareness on the dangers of tsunamis, and to educate the public on how the PTWS works to disseminate alerts on approaching tsunami, the ITIC, in cooperation with Chile, has produced a 6-minute outreach video. The aim of the video is to strengthen public and stake-holder agency knowledge of, and confidence in, tsunami alerts that save lives and reduce property damage.This video chronicles the tsunami warning chain for a M9.5 earthquake off Northern Chile as Pacific Tsunami Warning Center (PTWC) staff quickly analyze seismic and sea level data, forecast tsunami wave heights, and disseminate their threat assessments to country National Tsunami Warning Centers around the Pacific. Woven into this fast-paced video are vignettes highlighting tsunami warning and emergency response actions by centers and communities starting immediately after the earthquake in Chile and Peru, and after receiving the PTWC alerts in Samoa and Hawaii, and in Australia, Japan, Indonesia, and the Philippines.Para una versión española , por favor visite:youtu.be/aXx4pnVvz8IPour une version française , s'il vous plaît visitez : youtu.be/m4O_nnVslBQ
Five Years of Earthquakes in Chile PacificTWC 2015-02-26 | The 8.8 magnitude 27 February 2010 earthquake in central Chile was the largest in that country in 50 years. This animation shows that earthquake and all those recorded there in the following five years, including the 8.2 magnitude earthquake in northern Chile on 1 April 2014.For animations of the tsunamis generated by these two great earthquakes please see:2010, central Chile: http://youtu.be/RO16edaxoV02014, northern Chile: http://youtu.be/hhvfbjCIiXo-----El terremoto con magnitud 8.8 ocurrido el 27 de Febrero del 2010 in la region central de Chile constituye el más grande registrado en ese país en los últimos 50 años. Esta animación muestra ese terremoto y todos los registrados en los últimos cinco años, incluyendo el terremoto de magnitud 8.2 ocurrido al Norte de Chile el 1 de Abril del 2014.Para ver las animaciones de los tsunamis generados por estos dos grandes terromotos por favor vea:2010: http://youtu.be/RO16edaxoV02014: http://youtu.be/hhvfbjCIiX
A Decade of Tsunami Warning System Sensor Network Upgrades PacificTWC 2014-12-26 | The best-known tsunami-detection devices are the DART buoys. These buoys transmit data from their pressure sensors on the sea floor that measure tsunami waves passing over them. In 2004 we had only 8 DARTs, all in the Pacific Ocean. Today we use more than 60 DARTs worldwide.In addition to DARTs we also measure tsunamis with sea-level gauges located on coastlines. In 2004 we received sea-level data from about 150 of these coastal gauges, mostly in and around the Pacific Ocean. Today we receive sea-level data from more than 600 coastal gauges worldwide.Long before we can measure a tsunami we can detect and locate the earthquake that caused it. Therefore we use a global network of seismometers to record earthquakes as they occur and determine their tsunami-causing potential in real time. In 2004 we analyzed seismic data from about 120 seismometers worldwide. Today we use more than 650 seismometers worldwide.We can determine how these additional sensors have improved our performance using geospatial analysis techniques. If we treat the deep-sea trenches as megathrust earthquake sources, we find that we can detect and locate a megathrust earthquake about 5 minutes faster in 2014 than we did in 2004.We can perform a similar analysis for our sea-level instruments. We find that on average we can detect and measure a tsunami with at least 3 sensors (DARTs and/or coastal gauges) about 2 hours faster in 2014 than we did in 2004. The improvement is even greater in the Indian Ocean and the Caribbean Sea.In the years to come we will continue to add sensors to our network to further improve our tsunami warning capability.
A Decade of Great Earthquakes PacificTWC 2014-12-05 | December 2014 includes the 10-year anniversary of the 9.1 magnitude Sumatra-Andaman earthquake that generated the 2004 Indian Ocean Tsunami, one of the worst disasters in history with a death toll exceeding 200,000 people. In the decade following this event there have been many more tsunamis triggered by great earthquakes, and this animation shows all earthquakes in sequence at a speed of 30 days per second from 1 December 2004 to 30 November 2014, concluding with a map showing all earthquakes recorded in this span of time. It then transitions to a map showing just those earthquakes with magnitude 6.5 or greater (about 500 total), the smallest size known to generate a dangerous tsunami and thus the threshold PTWC typically uses to begin assessing tsunami risk. It then transitions one more time to a map showing earthquakes with magnitude 8.0 or greater (17 total), the "great" earthquakes that are most likely to pose a tsunami hazard if they occur near the sea floor.
Tsunami Animation: Three Tsunamis From Chile PacificTWC 2014-05-22 | This side-by-side comparison of three tsunamis generated within the same region highlights two important characteristics of tsunami behavior.First, the height of the tsunami waves (as shown by color) is strongly dependent on the size of the earthquake, namely its moment magnitude (Mw). The 9.5 Mw earthquake of 1960 released approximately 11 times more energy than the 8.8 Mw earthquake of 2010 and approximately 89 times more energy than the 8.2 Mw earthquake of 2014. Likewise, the tsunami wave heights were far larger in 1960 than they were in 2010, and larger in 2010 than they were in 2014.Second, the speed of a tsunami does not depend on the size of the earthquake. All three tsunamis move at about the same speed regardless of their size because their waves are so large that they interact with the sea floor. Therefore, both the ocean depth and its local variations control the speed of the tsunami waves.These two characteristics are critical for PTWC's ability to issue tsunami warnings. PTWC rapidly detects and analyzes earthquakes as they occur worldwide and use their estimated magnitudes to determine the level for the initial tsunami warning, if necessary. At the same time, tsunami waves move at a known speed about 50 times slower than earthquake waves, so PTWC can detect earthquakes and issue warnings well in advance of a tsunami's arrival at all coastlines except for those nearest to the tsunami-causing earthquake.To see the Mw thresholds PTWC uses to issue its initial guidance please visit: http://ptwc.weather.gov/ptwc/about_messages.php To see how these three earthquakes compare to other recent and historic earthquakes please watch: http://youtu.be/05kBRmJh3F8--------------------------------------------------------------------------------La comparación uno al lado del otro de tres maremotos ocurridos en la misma región intenta destacar dos importantes características del comportamiento de un maremoto:En primer lugar, la altura de las olas de un maremoto (como lo muestra su color) depende en gran medida del tamaño del terremoto, o sea, de su magnitud de momento (Mw). El terremoto con Mw=9.5 del 1960 liberó aproximadamente once (11) veces más energía que el terremoto con Mw 8.8 ocurrido en el 2010, y aproximadamente 89 veces más energía que el terremoto con Mw=8.2 ocurrido en el 2014. De forma similar, las olas correspondientes al maremoto del 1960 alcanzaron alturas muchísimo más altas que las generadas por el terremoto del 2010, y estas a su vez fueron muchísimo más grandes que aquellas generadas por el terromoto del 2014.En segundo lugar, la velocidad de propagación de un maremoto no depende del tamaño del terremoto, o sea, de su magnitud de momento (Mw). Los tres maremotos se propagan con una velocidad similar independientemente de su tamaño debido a que sus olas fueron tan grandes que interactuaron con el fondo oceánico. Esto quiere decir que tanto la profundidad del fondo oceánico como sus variaciones locales controlan la velocidad de las olas de un maremoto.Estas dos características juegan un papel fundamental en la capacidad del PTWC para emitir alertas de maremotos. El PTWC detecta y analyza los terremotos de forma muy rápida a medida que ocurren a lo largo y ancho del planeta, y utiliza las magnitudes estimadas para determinar, de ser necesaria, la severidad de la alerta inicial. Como las olas de un maremoto se mueven con velocidades cerca de 50 veces más lentas que las ondas sísmicas, el PTWC puede entonces emitir alertas con mucha antelación a su arrivo a cualquier línea costera, con excepción de las más cercanas al terremoto que genera el maremoto.Para ver los umbrales de Mw utilizados por el PTWC para emitir su orientación inicial por favor visite: http://ptwc.weather.gov/ptwc/about_messages.php Para ver como estos tres terremotos se comparan con otros terremotos históricos y recientes por favor vea: http://youtu.be/05kBRmJh3F8
Global Earthquake Animation: January - April 2014 PacificTWC 2014-04-30 | Earthquakes happen every day, and as this animation shows, small ones happen more frequently than once per hour. Moderate-to-large earthquakes are less common, however, perhaps 1-2 per month on a long-term average. Therefore April 2014 was unusual not in the total number of earthquakes that occurred but in how many moderate and large ones happened, and PTWC had to issue official message products for 13 different earthquakes in that month for earthquakes with magnitudes of 6.5 or higher, easily a record for this institution. Of those 13, PTWC issued tsunami warnings for 5: 1 April, M8.2, northern Chile 3 April, M7.8, northern Chile12 April, M7.6, Solomon Islands13 April, M7.7, Solomon Islands19 April, M7.8, Solomon IslandsThis animation shows all earthquakes on earth so far this year in sequence as recorded in the USGS's NEIC database (available at earthquake.usgs.gov). Note the typical level of activity through March. But starting with the 8.2 magnitude earthquake in northern Chile on April 1, the rest of the month saw 12 more moderate-to-large earthquakes mostly in Chile and the Solomon Islands but also in Nicaragua, Mexico, Canada, and even the south Atlantic Ocean. The animation concludes with a summary map showing all of the earthquakes in this four-month period.
Tsunami Animation: Iquique, Chile, 1 April 2014 PacificTWC 2014-04-02 | PTWC's near real-time animation for the tsunami from northern Chile on 1 April 2014 resulting from an offshore 8.2 magnitude earthquake in the region. The animation shows simulated tsunami wave propagation for 30 hours followed by an "energy map" showing the maximum open-ocean wave heights over that period and the forecasted tsunami runup heights on the coastlines.
Tsunami Animation: Unimak Island, Aleutian Islands, 1946 (rotating globe) PacificTWC 2014-04-01 | The Eastern Aleutian earthquake of April 1, 1946 spawned Hawaii's most damaging tsunami. The tsunami flooded all coastlines of all islands and resulted in 159 deaths. The tsunami arrived at about 6:45 a.m. local time and caught many people in Hilo in their houses; there were 96 deaths in that city alone. The tsunami was remarkable elsewhere in the Pacific as well. In the Marquesas, where, fortunately, it arrived late in the morning and so was widely recognized (only three people died there), the waves ran up on shore to a maximum elevation of 65 feet. In Hawaii the waves had reached "only" to 54 feet, on the north shore of Molokai.The earthquake itself has always been an enigma. At the time it seemed that its magnitude was 7.4. Modern corrections have increased that number substantially, but the official magnitude listed by the US Geological Survey is still only 8.1. In a careful analysis of the very few seismograms recording very long period energy, Lopéz and Okal in 2006 showed that the magnitude had to be at least 8.6. The huge difference between 7.4 and 8.6 (a factor of 64 in energy) is a measure of how much we have learned about earthquakes in the interim. We now know that the 1946 earthquake ruptured exceptionally slowly, radiating most of its energy at such low frequencies that most seismometers of the day could not even sense it. Fortunately, we now have broadband seismometers which can detect the missing energy: an earthquake off Java in 2006 displayed exactly the slow rupture proposed for the 1946 earthquake. With the Lopéz-Okal reevaluation of the 1946 earthquake, its huge tsunami on the Pacific now makes sense. As you see from this animation, the tsunami's energy is directed only slightly east of Hawaii (and directly at the Marquesas). What you see here are only the wave heights in the deep ocean. When we bring the tsunami into land and compute the inundation (sorry, those images are not yet ready for publication), we approximately reproduce what actually happened in 1946.To be prepared for such events, both the Pacific Tsunami Warning Center and the National Tsunami Warning Center now routinely test all large earthquakes for slow rupture, a test that yields results about ten minutes after the earthquake origin time (and therefore fast enough for most warnings). Slow rupture means large fault slip and large fault slip means a big tsunami, so this test is important.Our animation shows how this tsunami may have propagated in the north Pacific Ocean, followed by maps of calculated maximum wave heights, first on the open ocean and then at the coastline as determined by PTWC's forecast model using the 8.6 magnitude source of Lopéz and Okal (2006).(Mercator version: youtu.be/8Bi3o1HK0Ks)
Tsunami Animation: Prince William Sound, Alaska, 1964 (virtual globe) PacificTWC 2014-03-16 | One of the largest earthquakes ever recorded by instruments (and the largest ever in the United States) struck south-central Alaska on March 27, 1964 (local time). This 9.2 magnitude earthquake generated a tsunami that killed people in Alaska and California and damaged property in those states as well as in British Columbia, Oregon, and Hawaii. Our animation shows how that tsunami may have propagated in the Pacific Ocean 50 years ago and covers a 20-hour period finishing with an "energy map" showing the forecasted maximum heights of open-ocean tsunami waves followed by the forecasted tsunami runup on the coasts.As part of its response to this event the United States government created a second tsunami warning center in 1967, the Alaska Tsunami Warning Center--now called the National Tsunami Warning Center--to help mitigate future tsunami threats to Alaska, Canada, and the U.S. Mainland. Please see http://ntwc.arh.noaa.gov for more information about our sister Center.(Mercator version at: youtu.be/Lac4Zs_CIdw)
Tsunami Animation: Tohoku, Japan 2011 (rotating globe) PacificTWC 2014-03-11 | This animation shows how PTWC's real-time tsunami forecast model, RIFT, predicts the behavior of the tsunami following the 9.0 magnitude earthquake offshore of the Tōhoku-Oki region, Japan, on 11 March 2011. This version uses the USGS finite fault model (link below) as the source mechanism for the tsunami model, therefore the animation begins in "slow motion" to show the details of how the tsunami starts. The animation covers a 48-hour period finishing with an "energy map" showing the forecasted maximum heights of open-ocean tsunami waves over that time period, followed with the forecasted tsunami runup on the coasts. If you look carefully you will see not only the waves leaving Japan, but also the reflected waves leaving South America after about 23 hours.For a "flat earth" version, please see: http://youtu.be/EG507Y40d4UFor the earthquake and its aftershocks, please see: http://youtu.be/3r-JVx8yMpwFinite fault model: http://earthquake.usgs.gov/earthquakes/eqinthenews/2011/usc0001xgp/finite_fault.php
Tsunami Animation: Tohoku, Japan 2011 (Mercator) PacificTWC 2014-03-11 | This animation shows how PTWC's real-time tsunami forecast model, RIFT, predicts the behavior of the tsunami following the 9.0 magnitude earthquake offshore of the Tōhoku-Oki region, Japan, on 11 March 2011. This version uses the USGS finite fault model (link below) as the source mechanism for the tsunami model, therefore the animation begins in "slow motion" to show the details of how the tsunami starts. The animation covers a 48-hour period finishing with an "energy map" showing the forecasted maximum heights of open-ocean tsunami waves over that time period, followed with the forecasted tsunami runup on the coasts. If you look carefully you will see not only the waves leaving Japan, but also the reflected waves leaving South America after about 23 hours.For a "rotating globe" version, please see: http://youtu.be/feBtPsJH25cFor the earthquake and its aftershocks, please see: http://youtu.be/3r-JVx8yMpwFinite fault model: http://earthquake.usgs.gov/earthquakes/eqinthenews/2011/usc0001xgp/finite_fault.php
Tsunami Animation: Maule, Chile 2010 (rotating globe) PacificTWC 2014-02-26 | This animation shows how PTWC's real-time tsunami forecast model, RIFT, predicts the behavior of the tsunami following the 8.8 magnitude earthquake in Maule, Chile on 27 February 2010. The animation covers a 48-hour period finishing with an "energy map" showing the forecasted maximum heights of open-ocean tsunami waves over that time period, followed with the forecasted tsunami runup on the coasts.For the earthquake and its aftershocks, please see: http://youtu.be/hBhYV3B8_bw
Tsunami Animation: Maule, Chile 2010 (Mercator) PacificTWC 2014-02-26 | NEW VERSION AT youtu.be/oeKewmAoBEMThis animation shows how PTWC's real-time tsunami forecast model, RIFT, predicts the behavior of the tsunami following the 8.8 magnitude earthquake in Maule, Chile on 27 February 2010. The animation covers a 48-hour period finishing with an "energy map" showing the forecasted maximum heights of open-ocean tsunami waves over that time period, followed with the forecasted tsunami runup on the coasts.For a "rotating globe" version, please see: http://youtu.be/L2mz-dETib8For the earthquake and its aftershocks, please see: http://youtu.be/hBhYV3B8_bw
Meteotsunami Animation: U.S. East Coast, June 2013 PacificTWC 2013-12-09 | PTWC scientists used their tsunami forecast model, RIFT, to simulate how a weather-generated tsunami, or meteotsunami, may have propagated off of the east coast of the United States in the north Atlantic Ocean on June 13, 2013. A "derecho," or a rapidly-moving coherent storm front, traveled eastward across the US's mid-Atlantic states and out over the ocean as an atmospheric pressure anomaly. It appears in the animation as a prominent "negative" wave or trough in the sea's surface. It generates meteotsunami waves as it moves, and when it reaches the edge of the continental shelf (seen as a change from light blue to darker blue colors in the ocean) the waves jump or "spike" in amplitude there and propagate along the shelf's edge. The meteotsunami waves reflect landward from the shelf's edge due to the rapid change in wave velocity there (tsunami waves travel much faster in deeper water), then reflect again seaward from the coastline. Thus these waves become trapped in the shallow water of the continental shelf and oscillate back-and-forth for hours. If you watch carefully you can also see the polarity of the waves change when they reflect such that violet waves turn green and vice-versa. Some wave energy also escapes to deeper water where they travel much faster and with longer wavelengths. As the animation approaches 12 hours of simulated time it transitions to an "energy map" showing the maximum meteotsunami wave heights for this region, then concludes with a forecast of maximum calculated values of wave heights at the coastlines.This animation will be part of Wang et al.'s presentation on this topic at the 2013 American Geophysical Union Fall Meeting: http://fallmeeting.agu.org/2013
