This brochure provides an informative background on earthquake and seismic activity in Colorado and a general introduction to the science behind earthquakes, as well as instructions on what to do before, during, and after an earthquake. Unfolded, it features a full-size map of the entire state that shows historical and modern earthquake activity and the location of known or suspected faults active during the last two million years (the Quaternary Period). Digital PDF download. MI-95D
Based on Colorado’s historical earthquake record and geologic studies, an event as large as magnitude 6.5 to 7.5 could occur somewhere in the state. Scientists are unable to accurately predict when the next major earthquake will take place in Colorado, only that one will occur. Nearly 100 potentially hazardous faults have been identified across the state. Generally, these are faults thought to have had movement within the last 2 million years. There are other faults in the state that may have potential for producing future earthquakes. Because the occurrence of earthquakes is relatively infrequent in Colorado and the historical earthquake record is relatively short (only about 130 years), it is not possible to accurately estimate the timing or location of future dangerous earthquakes in Colorado. Nevertheless, the available seismic hazard information can provide a basis for a reasoned and prudent approach to seismic safety.
More detailed information on Colorado earthquakes, faults, and geology may be found on the CGS website where there is a reference collection on Colorado seismicity and an earthquake and fault map.