Lidar shows the scars of a pre-Helene flood near Spruce Pine (1901 event) TheGeoModels 2026-09-22 | Lidar shows the scars of a pre-Helene flood near Spruce Pine (1901 event)
Model landslides with toe removal and reactivation TheGeoModels 2023-03-29 | This video shows how landslides respond to removal of their "toe," or the material pushed out at the base of the slide. The frictional strength within this toe and between the toe and the underlying ground provides a support for the slide that resists additional slide movement. When the toe is removed, resistance to sliding is lowered, and the slide moves again.
Geologic setting of Vienna Basin hydrogeothermal projects | Geology Models TheGeoModels 2023-02-22 | ...
Why is this Cameroon volcano the most interesting volcano on Earth? | Geology models TheGeoModels 2023-02-13 | youtube.com/watch?v=QDOyGCDXy1gMt. Cameroon is a large, active volcano near the coast of Cameroon. It has produced spectacular and dangerous eruptions, but its most interesting aspect is its sheer size and what its weight does to the underlying and surrounding rocks. This video shows how Mt. Cameroon's mass has shaped the surrounding landscape in a way unlike any other volcano on Earth.
The steepest mountain in the world is in Cuba????? | Caribbean geology TheGeoModels 2023-02-10 | Qomolongma (Mt. Everest) and the Big Island of Hawai'i both get hype as Earth's greatest mountain, but there's a mountain in the Caribbean Sea that beats them both in terms of sustained steepness. Its long-distance slope steepness from the base of the Cayman Trench to its summit is exceeded nowhere else on the planet over. This mountain probably pushes the limits of what Earth's rocks can support under the force of Earth's gravity. It's on the south coast of Cuba, and most people haven't even heard of it.
Can we make landslides stop moving? | Engineering Geology Models TheGeoModels 2023-02-02 | Landslides disrupt property and infrastructure, but dealing with them isn't as easy as simply restoring the shape of the original slope. This video uses a scale model to show how changes to an existing landslide can cause it to keep moving.
Earthquake-induced landslides: Lateral spreads and liquefaction | Geology Models TheGeoModels 2023-01-30 | Earthquake shaking can cause some sediment layers to liquify, which allows overlying layers to slide and spread apart in a lateral spread landslide. The Turnagain neighborhood near Anchorage, Alaska, was heavily damaged by a lateral spread slide during the 1964 Alaska earthquake. This video shows models of lateral spread landslides that develop when a layer of glass microbeads "liquifies" during shaking.
1811-1812 New Madrid earthquake damage...see it with LiDAR | Geology Models TheGeoModels 2023-01-23 | Delano paper (with Ryan Gold and others!)agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2018GL080493The huge New Madrid earthquakes of 1811-1812 created Reelfoot Lake and temporarily backed up the Mississippi River, but they also shook hills in the surrounding landscape until they spread and cracked. This video shows was the process looks like and uses LiDAR imagery to reveal what the shaken ridges really look like.
Using LiDAR to find mountain landslides TheGeoModels 2023-01-17 | This video shows how LiDAR imagery can be used to find landslides on forested mountainsides. LiDAR imagery is a great way to see the details of mountain landscapes, particularly in the Appalachian Mountains. Landslides that may not be moving now can be brought back to life by development, so a full understanding of what mountainsides "really" look like is important. More and more people are building homes in the North Carolina mountains, but some areas are too high risk. LiDAR helps identify them.
The Keping fold and thrust belt: Chinas colorful other rainbow mountains | Geology Models TheGeoModels 2023-01-08 | Copy and paste either set of coordinates into Google Earth or Google Maps:39.963558N, 76.935083E39.829482N, 77.367644EChina's Keping thrust belt produces awesome exposures of multi-colored sedimentary rocks where they are upturned and eroded above thrust faults. I made a simple sandbox model that illustrates the underlying structures that produce the belts of colored rock exposed in the real-life mountains. The model shown in the video was "eroded" (carved) in detail after it was gelled and partially dried.
Central peak formation in model impact craters TheGeoModels 2021-03-21 | This video shows how a central peak forms in a model impact crater. The craters are produced by shooting a sand and microbead layer pack with a lead pellet from a high-power air rifle. The layer pack consists of a thin, "strong" (high friction due to angular particles) sand layer atop a thicker layer of glass microbeads, which are spherical and treated to have low friction against one another. This layer combination appears to be necessary to form a central peak with the impactor used; sand or microbeads alone won't do it. Overall, the formation of the central peak is much like the splash that occurs when a pebble is dropped into calm water. I don't know how these models scale to real planetary bodies. The microbeads are necessary for the developing crater to contain "strength-less" material in its transient phase. The strengthless beads behave in a fluid-like fashion as they collapse inward to restore an equilibrium with gravity and their surroundings.
Slump landslide model and the cracks of the Llusco landslide, Lutto Kututo, Peru TheGeoModels 2020-05-04 | ...
Geology of the Rocky Mountains Front Range and The Garden of the Gods TheGeoModels 2019-03-15 | This video shows how sedimentary layers were tilted vertical and then exposed by erosion to produce the interesting rock formations at the foot of the Colorado Front Ranges. The model is not perfect--it was allowed to run a bit too long, and it cannot demonstrate compensation for thrust loading of the crust, but it does give an idea of how the layers were tilted in front of deep crustal rocks and then unburied by regional uplift and erosion.
The Breaks Slide: A translational rockslide in dipping sedimentary rock TheGeoModels 2019-03-07 | This video shows LiDAR imagery of the Breaks Slide (Schultz and Southworth, 1989) and presents a simple analog model showing translational slide movement. The translational slide is compared to a Toreva-block slide, which moves on a curved failure surface and is commonly seen on cliff lines in the western US.
LiDAR hillshade-geologic map comparisons, Big Stone Gap quadrangle, Virginia TheGeoModels 2019-02-15 | Companion to this blog post:geomodelsvt.wordpress.com/2019/02/15/a-lidar-perspective-on-a-1965-geologic-map
LiDAR, hillshade imagery, and a cool translational landslide TheGeoModels 2019-01-06 | Hillshade imagery produced from National Map (USGS) LiDAR elevation data reveals a large, thin translational landslide in southwest Virginia.
Thick-skinned mountain range: New Guineas Mapenduma Anticline TheGeoModels 2018-12-15 | Re-upload of original video due to text error (sorry!). Video shows development of a "thick-skinned" mountain system, in which continental crust is involved in faulting in the frontal parts of the thrust belt. West Papua's impressive Mapenduma Anticline, home of Puncak Jaya, is used for a comparison. This structural feature produces an abrupt 5 km of topography, and is geologically young, having developed during the last ~ 8 million years.
Antiformal stacks and passive roof faults: Llanos Foothills and Madre de Dios basin TheGeoModels 2018-11-09 | Decollements and focused erosion are used to develop tight antiformal stacks composed of slices of a relatively thin stratigraphic interval
Restraining bend with erosion TheGeoModels 2018-11-01 | McClay et al. (1990) is the best restraining bend model paper, but the models are un-eroded during shortening or buried with syn-tectonic growth. This very basic model is intended for comparison to tropical latitude restraining bends, which experience intense syn-tectonic erosion.
Basin inversion by buried faults, compared to Don Figuerero and Santa Cruz Mountains, Jamaica TheGeoModels 2018-10-31 | Check out Benford et al. (2014) in Lithosphere for a good discussion of the setting. This model uses an elastic base to develop "domino block" extensional structures which impact reverse faulting during compression.
Bottomless waterfall plunge pool near Bath Fountain, Jamaica TheGeoModels 2018-10-23 | Just for fun I stuck an iPhone with a Lifeproof case in the water to try to see what the bottom looked like. I didn't look at the video until later, or I would have taken a better one! I don't know how deep this pool is, but it's impressive!
Fold thrust belt model with decollements TheGeoModels 2018-10-10 | High contrast between layer strength produces a "flat-on-flat" geometry. This structural style is seen in thin-skinned fold-thrust belts around the world.
Model impact craters, from a structural geologists perspective TheGeoModels 2018-09-30 | Model impact craters produced in a sandpack using a high-velocity pellet gun. I made these models to see 1) how the sandpack responded to the impact stress and 2) from where in the geologic section ejecta was derived. The results are interesting, and bear some similarities to real impact features. Scaling the behavior of the projectile is obviously an issue, as is the lack of melting, but the overall result is interesting!
Fold-thrust belt: Stress field and fault orientations in a simple model TheGeoModels 2018-09-09 | This video shows how bedding plane detachments form in a fold-thrust model. It's all about stress field and the angle of internal friction of the layers involved.
Normal fault inversion...at least a little bit TheGeoModels 2018-08-12 | Another look at compression a sandpack that has been deformed by extension. In this elastic base model, early normal faults rotate to lower dip, and some experience localized reactivation during shortening. To get more fault reactivation/inversion, materials of strong mechanical contrast and appropriate orientation to stress field would be needed. I also think sidewall drag is a problem here, so stay tuned for an open sided model that I will cut into slices.
Normal fault sandbox model: Rift-style faulting using a stretching base layer TheGeoModels 2018-05-03 | This model uses a stretching base layer to produce normal faults in a sandpack. All models are run on a horizontal surface, but an oblique camera angle is used to capture the lengthening deformed area. This is a tough model to make due to the "necking" of the sandpack, but this result worked out well enough to show the basic idea. Structures of the type shown here are significant to hydrocarbon exploration in settings around the world. Seismic images from the Andaman Sea and North Sea are shown.
Relay ramps and normal faults: Examples from Afar Rift, Lake Tanganyika, Lake Baikal TheGeoModels 2018-03-21 | ...
Normal faulting in rift or basin-and-range style settings TheGeoModels 2018-03-09 | More geology content here: wordpress.com/view/geomodelsvt.wordpress.com
Landslides: Slumps (rotational) and translational slope failures TheGeoModels 2018-02-16 | More content here: wordpress.com/view/geomodelsvt.wordpress.com This video uses small models to compare the movements associated with rotational slides (slumps) and translational slides. These movements are difficult to film, so the focus is not the best, but hopefully the idea is communicated. The model setup is tapped to initiate the slides, so some vibration is apparent as movement starts during each experiment.
Shale in fold thrust belts: Triangle zones and passive backthrusts TheGeoModels 2017-12-13 | This model uses strong layers and weak microbeads to demonstrate passive roof faulting in a mixed stratigraphy of weak and strong layers. These passive faults involve little displacement, but they would impact cleavage/fracture development in the shale. One model develops the relative backthrust movement through limb rotation; another uses a stratigraphic pinch-out. These models would be improved by weakers detachment layers, but the general style is communicated here.
Weak layers in fold-thrust belts: Shale sandwich slip horizons TheGeoModels 2017-12-08 | This video uses the same materials as the antiformal stack model without high basal friction to show how weak rocks, like shale, can be "badly" behaved during thrust belt development. When "sandwiched" between strong, brittle horizons, shale intervals attract fault development and experience internal deformation separate from layers above and below. As a result, dip data and structural style from a shale horizon may be very misleading if you try to use them to produce a deep cross section! Data from stronger, thickness-holding intervals is necessary to develop geometric constraints from surface data.
Simple landslide model: Translational slide TheGeoModels 2017-11-18 | This model demonstrates a simple translational slide, where a mass of material detaches in a weak horizon and glides parallel to the horizon. This type of slide often occurs in tilted sedimentary rocks, where strong layers, like sandstone, detach and slide downslope along weak layers, like shale or gypsum. Results are compared to large, ancient slides in southwest Virginia, identified by Schultz, Southworth, and others, 1986-1993.
Identifying thrust faults and normal faults: Triton Bay, West Papua (northwest New Guinea) TheGeoModels 2017-10-26 | A simple video showing what it looks like when normal faults cut across older structures related to thrust faulting. Triton Bay's rectangular shape is the result of the graben that hosts it. In Google Maps Terrain, it's easy to see the crests of anticlines that have collapsed/subsided with development of the graben.
Whats inside the mountains? (Antiformal duplex stack model) TheGeoModels 2017-10-01 | This model uses two detachment surfaces of contrasting strength to produce an antiformal duplex stack with associated flexed, synclinal thrust sheets. This structural style is interpreted in all of the Earth's collisional mountain ranges at the large scale, and is common in external fold-thrust belts at the smaller scale when more than one slip surface (two separate shale horizons, for example) are present. Antiformal stacks represent huge "piles" of the same rock type in one stack, and their presence can be seen in localized gravity anomalies associated with such a thick mass of a single rock type!
Geologic Map sample Catawba 1:24k map, Virginia TheGeoModels 2017-09-07 | A quick look at what a geologist sees in the landscape...
Desktop mountain building model TheGeoModels 2017-09-01 | In this model, a thin layer pack sits on a sheet of paper which is pulled against a backstop (a rigid "continent"). It's as basic as it gets...but it still produces the types of patterns you can see in the real world. All you need to do this is a long sheet of paper, some very fine colored sand, and some sort of anchored backstop that the paper can slide under to have the sand layers scraped off of its surface. If you want to see what's inside the model, check out the video about gelling and slicing models below. Ironically, the sand sold at Hobby Lobby is BY FAR the best material for this type of simple desktop experiment. It's extremely fine and makes beautiful, crisp structures at this small scale.
Fold-thrust belt topography: The Ouachita Mountains, whetstone capital of the world TheGeoModels 2017-06-26 | This video shows how different sedimentary rock types folded into distinct structures control topography in the Ouachita Mountains of Arkansas and Oklahoma. The chert, or novaculite, ridges in this area are sources of raw materials for making the world's finest natural sharpening stones. Novaculite is essentially slightly recrystallized chert, and the extremely high silica content and fine grain produce an outstanding abrasive stone for honing fine edges onto steel tools. These whetstones are often sold as "Arkansas Stones" or "Ouachita (Washita) Stones," and have been produced in the area since the early 19th century. The original users of the material were, of course, Native Americans in the region, who produced exceptional points and cutting tools from the conchoidally-fracturing novaculite.
Gelling a model Part 2 TheGeoModels 2016-12-28 | Per request...a video showing the process I use to gel and slice models for drying and preservation.
Gelling a model Part 1 TheGeoModels 2016-12-28 | Per request...a video showing the process I use to gel and slice models for drying and preservation.
Restraining and releasing bends with erosion during deformation...and cross sections TheGeoModels 2016-12-01 | ...
Nepal Himalaya model: 2 decollements, intense erosion, and context of 2015 Gorkha earthquake TheGeoModels 2016-11-10 | Link to Perrin et al. (2013)researchgate.net/publication/260694059_Impact_of_erosion_and_decollements_on_large-scale_faulting_and_folding_in_orogenic_wedges_Analogue_models_and_case_studiesA 2-decollement model produced with intense erosion. Final structural style is comparable to interpretations of east/central Himalaya. Growth of an antiformal duplex stack arches overlying thrust sheets to produce a window and klippe. The model also provides a glimpse at the structural setting of the 2015 Gorkha earthquake in Nepal, which resulted from rupture of the main Himalaya sole thrust beneath the outer edge of the antiformal stack.
Basin inversion with varied mechanical stratigraphy: Shale and limestone/sandstone TheGeoModels 2016-09-20 | ...
