WSGS Surficial Processes Group
Seth Wittke
Geologist: Surficial Processes
(307) 766-2286, Ext. 244
wittkesj@uwyo.edu
Surficial Geology
Surficial geology is the study of landforms and soils on the surface of the earth. Surficial processes are those geologic processes that affect landforms and soils, often to the detriment of human societies. The Surficial Processes Group investigates active faults, earthquakes, landslides, floods, and other surficial geology. We compile and catalogue these data and provide concise, accurate information about surficial processes in Wyoming. Related reports, digital maps, and conventional maps are available from Publications or by contacting us. Coordination with government, public, and private parties is an important function of the Surficial Processes Group. Information on some surficial topics follows.
Aerial Photography
The Surficial Processes Group maintains files of aerial photo series covering much of Wyoming. If you are interested in using these images, please stop by the WSGS office or contact us: anyone may use the images, but must do so at the WSGS office.
Active Faults
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Faults in Wyoming are considered active if they have shown displacement or seismic activity during the Holocene Epoch (the last 12,000 years). The Teton Fault, located in Jackson Hole, is the most famous of the active faults, though there are numerous other active faults around the state. Click here to view a map of active faults. |
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Landslides
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Landslides (often called mass wasting) occur when a slope becomes unstable. Rock falls, debris flows, slumps, and creep are all types of landslides. Landslides can cause considerable damage: they can cover or destroy roads, carry houses downslope, and temporarily block rivers with unstable earthen dams, which cause flash-flooding downstream when compromised. The WSGS has mapped more than 30,000 landslides in Wyoming, and maintains a database of these locations. As new landslides occur, we catalogue them and add them to the database. To view the database, click here. To view a landslide map, click here. |
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Earthquakes
Earthquakes happen in Wyoming every day, but are rarely strong enough to be felt, even by people nearby. Most earthquakes occur in western Wyoming, particularly in the northwestern corner (Yellowstone National Park); however, earthquakes occur and are felt in the eastern half of the state as well. The WSGS keeps a database cataloguing earthquake events in Wyoming. The following links will take you to various earthquake tracking sites.
• 100 years of earthquakes 1871-1970
• USGS Earthquake Search 1973-current
• University of Utah Yellowstone EQ listings
• Earthquake Hazards Program Intermountain West IMW Region
Earthquakes in Wyoming-Information pamphlet
Windblown Deposits
Windblown deposits form when sand, silt, or clay (loess) materials are transported by wind and deposited on the ground surface. Although windblown deposits are not normally a catastrophic event, they can cause damage to or loss of property. Active windblown deposits occur in many areas of Wyoming, particularly northeast of Rock Springs, north of Sinclair, northwest of Casper, and in Goshen County. Stable windblown deposits (those that have become vegetated) may become active again if they are disturbed and not properly re-vegetated or stabilized. To view a map of windblown deposits, click here.
Shrinking/Swelling Soils
Prehistoric volcanic ashfalls weather to form bentonite, a swelling clay found in many soils. Changes in soil moisture cause certain clay minerals in soils to either expand or contract, often resulting in large volumetric changes in the soil. If structures or roads are built on these soils without proper mitigation procedures, the expansion or contraction of the soil can cause cracking, movement, or even failure of a structure. To view a map of shrinking/swelling soils, click here.
Surficial Geology Maps
The Surficial Processes Group has compiled 1:100,000-scale surficial geologic maps for much of Wyoming. Refer to the Surficial Index Map. We continue to map the surficial geology of Wyoming in conjunction with the USGS National Cooperative Geologic Mapping Program. Please see the WSGS mapping webpage for more information.
Floods
The Surficial Processes Group keeps Wyoming Flood Insurance Rate Maps, and has complied these data into an interactive database. These maps can also be found on the Federal Emergency Management Agency (FEMA) website.