Colorado

Colorado is moderately seismically active.

An excerpt from the article 29 facts about Colorado

Despite its mountainous terrain, earthquakes are not frequent, and if they do occur, they are of low magnitude.

Since 1973, 525 earthquakes have been recorded there, most of which were between 2 and 3.5 on the Richter scale. A magnitude 5.7 quake was recorded in 1973.