Secular strain and earthquakes near Denver



About 1600 earthquakes of Richter magnitude 0.7–5.3 have occurred in NE Denver since April 24, 1962. These events have a normal frequency vs magnitude distribution (b is about 0.8) and therefore cannot be considered to have reduced the probability of the future occurrence of a larger event.

This report describes (1) certain gross features of the active zone, (2) a source mechanism for the largest event to date, and (3) the strain variations, at a point in the active zone, since November 1967.