Last night southwestern Colorado was shaken by a magnitude 5.3 earthquake centered 9 miles southwest of Trinidad. Large earthquakes are not frequently experienced here in the Rocky Mountains, but low magnitude quakes are fairly common. The Colorado Geological Survey maintains a database called the Colorado Earthquake Mapserver which contains information on all of the cataloged earthquakes in Colorado, and also shows the faultlines that run through the state. The CGS also has an earthquake website with basic information on Colorado quakes, including case histories, maps and facts about earthquake damage ratings. Facts about last night’s earthquake can be found on the U.S. Geological Survey’s website. They also have an interesting history of Colorado earthquakes that is worth checking out.