Source: Colorado Natural Hazards Mitigation Council Annual Report, 1991-92 --

The table below lists some of the significant earthquakes felt in Colorado since 1870. As you can see by looking at the table, although the general seismicity rate of Colorado may be considered low, the rates are consistent with a magnitude 6 or larger earthquake occurring within our lifetimes. The geologic record suggests that parts of Colorado have repeadedly experienced earthquakes of up to magnitude 6.5 to 7.5 during the past million years.

Significant Colorado Earthquakes

There are more than 200 known, potentially active faults within Colorado's complex geological structures. In addition to known faults, seismograph instruments have recorded seismic activity in other areas of Colorado where earthquakes have been felt, but where faults were not visible to geologists.

Many of Colorado's lifelines, such as power and other utility lines, are at risk from earthquakes. In addition, infrastructure, special facilities, and critical facilities are at risk from earthquakes and other natural disasters in Colorado. The primary infrastructures and lifelines threatened by earthquakes are:

• power plants and transmission lines
• natural gas and petroleum lines
• highways and bridges
• dams and irrigation infrastructure
• airport facilities and runways
• railways
• water lines

In addition, the following special and critial facilities are at risk:

• hospitals and health care facilities
• schools and universities
• state, local, and federal government facilities and operational capabilities
• high rise, high occupancy buildings
• telecommunication facilities
• sports stadiums
• nuclear power plants
• toxic waste sites

Definitions and Introduction | The Modified Mercalli Intensity Scale | The Richter Magnitude Scale | Colorado's Seismic Risk | Secondary Hazard Events | Survival Tips