Geologic Hazards

Landslide Summary Report
Landslide Fact
Sheet

Wyoming is known for its remarkable variety of natural landscapes. From snowcapped mountains to deep canyons, high deserts to Yellowstone – Earth’s geologic processes constantly shape the Wyoming landscape. These geological processes can be accountable for periodic and destructive geologic hazards that can impact people and infrastructure.Geologic hazards in Wyoming are numerous and vary widely from sudden events, including earthquakes, landslides, and volcanic eruptions, to slow processes such as windblown deposits and expansive soils.

Earthquakes occur daily in Wyoming but are often not strong enough to be felt by people. Most of the state’s earthquakes occur within the Yellowstone region and western Wyoming; however, earthquakes do occur in other areas of the state. Quaternary Faults are faults that have been identified at the earth’s surface displaying evidence of movement in the past 1.6 million years. Faults are considered active during the last 10,000 years if there is evidence or observations of seismic events.

Landslides can cause major losses to infrastructure, such as roads and property causing millions of dollars in damage. However, in Wyoming, most landslides occur in remote areas of the state and do not typically cause damage.

Volcanic eruptions can produce a variety of geologic hazards, including airborne debris (ash), earthquakes, hot gasses, landslides, and hydrothermal explosions. Over the last 2 million years historic eruptions associated with the Yellowstone hot spot have covered vast areas of North America with ash. The last major caldera-forming eruption to occur created the present day Yellowstone caldera, approximately 640,000 years ago. Not all volcanic eruptions in Yellowstone are catastrophic events. The most recent volcanic eruption, a lava flow creating the Pitchstone Plateau, occurred 70,000 years ago.

Expansive soils shrink and swell when subjected to changes in moisture. Highways, structures and utility lines are susceptible to damage from expansive soils resulting in maintenance and replacement costs.

Windblown deposits form when sand, silt, or clay (loess) materials are transported by wind and deposited on the ground surface. These deposits can cover roadways, agricultural lands, and encroach on structures. Stable windblown deposits (those that have become vegetated) may become active again if they are disturbed and not properly re-vegetated or stabilized.

The WSGS Geologic Hazards Group is focused on identifying and characterizing geologic hazards throughout the state. Hazard geologist’s carry out research, compile and analyze data, create hazard maps, produce reports, and address geologic hazards to better assist the public, state and federal agencies, and county planners.


EarthquakesLandslidesYellowstone

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