Earthquakes are caused by a sudden movement of the earth along a fault. As the rocks on either side of the fault accumulate stress between them, they will eventually overcome friction and slip. The resulting earthquake releases energy in waves that travel through the Earth’s crust. These waves can cause noticeable shaking at the surface and, in the case of large earthquakes, damage to roads, buildings, and other infrastructure that may pose a threat to public safety.
Colorado is considered an active tectonic province that is essentially being pulled apart where the Rio Grande Rift cuts north/south across the mountainous, central part of the state. Colorado’s high mountains are a result of uplift on faults (with associated earthquakes) that are part of the rift system. The active landscape of the state — with the still-rising mountains containing thousands of faults — features over 90 potentially active faults and more than 700 recorded earthquakes of magnitude 2.5 or higher since 1867. Colorado experiences fewer and less frequent earthquakes on average than more seismically active states like California. However, the state has experienced large natural (magnitude 6.5 or higher) and human-triggered (induced) earthquakes in recorded history and will continue to periodically experience large earthquakes in the future.
Earthquake hazard is the likelihood of a certain level of shaking, also known as “Peak Ground Acceleration,” that may occur from an earthquake in a particular area. Colorado has low-to-moderate earthquake hazard as rated by the U.S. Geological Survey Earthquake Hazards Program. Earthquake risk is the likelihood of economic or personal loss occurring from an earthquake in a particular area, and is determined by looking at the level of earthquake hazard, the number of people and properties in the hazard area, and the vulnerability of people and infrastructure to earthquakes. Knowledge of both hazards and risk are vitally important in the resilience planning for earthquake events.
Earthquakes can cause damage to buildings and infrastructure directly through shaking, but they are sometimes also responsible for causing related hazards, such as ground fissures, soil liquefaction, landslides and rockfalls, and more. In order to reduce risks from earthquake-associated hazards, it is important to study local geology and soil conditions.
Because fault movement causes earthquakes, it is important to study the thousands of faults in Colorado to determine whether they have moved in the recent geologic past or capable of moving again in the near future. The CGS conducts scientific studies of fault zones and past earthquakes while monitoring fault movements with a network of seismometers throughout Colorado.
Three faults in Colorado have received sufficient study to be included in the USGS National Seismic (Earthquake) Hazard Map, and are listed as being capable of generating earthquakes of 7.0 magnitude, or greater. There are many more faults in the state that could probably generate significant earthquakes, but have not received sufficient study, or documentation, to be included in the hazard map. With our current state of knowledge, it is not possible to predict when or where, the next large earthquake might occur in Colorado.
The latest recording traces from some of our seismic stations (the trace images are refreshed automatically on reload):
ON-001 — Colorado Earthquake and Fault Map —
County-based HAZUS reports — A primary resource for planners and emergency responders state-wide.
Colorado Earthquake Hazards Mitigation Council. “MI-95 Colorado Earthquake Hazards.” Colorado Geological Survey, Department of Natural Resources, 2013. https://coloradogeologicalsurvey.org/publications/colorado-earthquake-hazards.
Colorado Geological Survey. “RockTalk V05N2, April 2002 – Earthquakes in Colorado.” RockTalk, April 2002.
Colorado Geological Survey and CEHMC. “OF-20-08 Earthquakes in Colorado.” Colorado Geological Survey, July 4, 2020. https://coloradogeologicalsurvey.org/publications/earthquakes-in-colorado.
Kirkham, R. M., W. P. Rogers, L. Powell, M. L. Morgan, V. Matthews, and G. R. Pattyn. “Bulletin 52B – Earthquake and Late Cenezoic Fault and Fold Map Server.” Earthquake. Bulletin. Denver, CO: Colorado Geological Survey, Division of Minerals and Geology, Department of Natural Resources, 2004. https://cgsarcimage.mines.edu/ON-001.
Kirkham, Robert M. “OF-78-03 Earthquake Potential in Colorado: A Preliminary Evaluation.” Earthquakes. Open File Reports. Denver, CO: Colorado Geological Survey, Department of Natural Resources, 1978. https://coloradogeologicalsurvey.org/publications/earthquake-potential-colorado-1978.
Kirkham, Robert M., David C. Noe, Lauren Heerschap, James P. McCalpin, Shannon Mahan, and Matthew L. Morgan. “MI-100 Summary Report on the McQueary Gulch Trench, Williams Fork Mountains Fault, Grand County, Colorado.” Paleoseismic. Miscellaneous Investigations. Golden, CO: Colorado Geological Survey, June 2020. https://coloradogeologicalsurvey.org/publications/mcqueary-gulch-trench-williams-fork-mountains-fault-grand-colorado/.
Kirkham, Robert M., and William P. Rogers. “Bulletin 43 – Earthquake Potential in Colorado: A Preliminary Evaluation.” Earthquake. Bulletin. Denver, CO: Colorado Geological Survey, Department of Natural Resources, 1981. https://coloradogeologicalsurvey.org/publications/earthquake-potential-colorado.
———. “Bulletin 46 – Colorado Earthquake Data and Interpretations 1867-1985.” Earthquake. Bulletin. Denver, CO: Colorado Geological Survey, Department of Natural Resources, 1985. https://coloradogeologicalsurvey.org/publications/colorado-earthquake-data-interpretation-1867-1985.
———. “Bulletin 52 – Colorado Earthquake Information, 1867-1996.” Earthquake. Bulletin. Denver, CO: Colorado Geological Survey, Division of Minerals and Geology, Department of Natural Resources, 2000. https://coloradogeologicalsurvey.org/publications/colorado-earthquake-information-1867-1996.
———. “OF-86-08 An Interpretation of the November 7, 1882 Colorado Earthquake.” Earthquake. Open File Report. Denver. CO: Colorado Geological Survey, Department of Natural Resources, 1986. https://coloradogeologicalsurvey.org/publications/interpretation-november-7-1882-colorado-earthquake.
Morgan, Matthew L. “OF-03-04 Published Faults of the Colorado Front Range.” Faults. Open File Reports. Denver, CO: Colorado Geological Survey, Division of Minerals and Geology, Department of Natural Resources, 2003. https://coloradogeologicalsurvey.org/publications/published-faults-front-range-colorado.
Morgan, Matthew L., and F. Scot Fitzgerald. “ON-001 Colorado Earthquake and Fault Map.” Earthquake, (variable) online map. Golden, CO: Colorado Geological Survey, July 1, 2019. https://cgsarcimage.mines.edu/ON-19-01/.
Morgan, Matthew L., and Karen S. Morgan. “OF-11-06 Preliminary Damage Report of the August 22, 2011 Mw 5.3 Earthquake near Trinidad, Colorado.” Earthquake Damage. Open File Report. Denver, CO: Colorado Geological Survey, Department of Natural Resources, September 2011.
Nuhfer, Edward B., Richard J. Proctor, and Paul H. Moser. MI-57 The Citizens’ Guide to Geologic Hazards: A Guide to Understanding Geologic Hazards, Including Asbestos, Radon, Swelling Soils, Earthquakes, Volcanoes, Landslides, Subsidence, Floods, and Coastal Hazards. Westminster, CO: The American Institute of Professional Geologists, 1993.
Oaks, Sherry D., and Robert M. Kirkham. “IS-23 Results of a Search for Felt Reports for Selected Colorado Earthquakes.” Earthquakes. Information Series. Denver, CO: Colorado Geological Survey, Department of Natural Resources, 1986. https://coloradogeologicalsurvey.org/publications/felt-reports-colorado-earthquakes.
Rogers, William P., and Robert M. Kirkham. “SP-28 Contributions to Colorado Seismicity and Tectonics – A 1986 Update.” Seismicity and Tectonics. Special Publication. Denver, CO: Colorado Geological Survey, Department of Natural Resources, 1986. https://coloradogeologicalsurvey.org/publications/colorado-seismicity-tectonics-1986.
“SP-19 Colorado Tectonics, Seismicity and Earthquake Hazards: Proceedings and Field Trip Guide of a Symposium Held in Denver, Colorado, June 4-6, 1981.” Tectonics, Seismicity, and Earthquake. Special Publication. Denver, CO: Colorado Geological Survey, Department of Natural Resources, 1981. https://coloradogeologicalsurvey.org/publications/colorado-tectonics-seismicity-earthquake-hazards.
USGS Hazards Program – Colorado Information — USGS’s Colorado Earthquake Hazards page. Info about Colorado seismicity, hazard maps, and Colorado specific earthquake topics.
Denver Basin Earthquake Studies — Website for induced seismicity project in Weld County Colorado by researcher Anne Sheehan at the University of Colorado.
The Great Colorado ShakeOut — Colorado page for the nation wide earthquake drill. Info on earthquake drill procedures and numerous tips for earthquake preparedness.
Colorado Division of Homeland Security and Emergency Management – Earthquakes — State of Colorado’s webpage on Colorado earthquake hazards. Info on earthquake preparedness as well as links to additional preparedness resources.
Colorado Earthquakes — YouTube video about Colorado earthquakes.
Federal Emergency Management Agency Earthquakes — FEMA’s earthquake risk page. Info about federal earthquake hazard maps, federal funding for risk management and building codes.
U.S. Geological Survey Earthquake Hazards Program — USGS’s earthquake hazards page. Info on faults, hazard maps, and earthquake ground motion.
USGS Earthquake Notification Service — A customizable service for receiving notifications about any earthquakes nationally and internationally, within five minutes of occurrence.
WSSPC — Western States Seismic Policy Council, a non-profit earthquake consortium for the western states
Induced Earthquake Bibliography — This comprehensive bibliography contains several hundred references to publications concerning earthquakes and other seismicity induced by human activity.