Nevada Earthquake: A M=4.4 struck the Mount Rose Fault Zone in south Reno, Nevada

A shallow magnitude 4.4 quake struck the Mount Rose Fault Zone in south Reno, Nevada, this morning. The Nevada earthquake, its foreshocks and aftershocks struck 10 miles south of Downtown Reno, and 15 miles northeast of Mount Rose Ski Tahoe resort. The sequence has elements of swarm-like behavior, with three magnitude 3 and larger quakes in the 24 minutes preceding the M=4.4 shock.

The Mount Rose fault zone is about 30 miles long, extending south from Reno almost to Lake Tahoe. It accommodates east-west Basin and Range stressing, and so is called a ‘normal fault.’ It has a slip rate of 1-5 millimeters each year, which makes it quite active, particularly among the normal faults that lace Nevada and eastern California. However, the Mount Rose Fault is broken up at the surface into hundreds of small segments, which makes its ability to produce a magnitude 7 earthquake uncertain. These segments might join at depth, in which case large quakes are likely. Evidence from trench excavations across some of the fault strands suggest large slip events have occurred in the past several thousand years, with slip of 2-4 meters, as would occur in magnitude 7 earthquakes. Thus, the potential for larger quakes is quite real and important.

Ross Stein, Temblor CEO
Data from the USGS,  Nevada Seismological Laboratory, Nevada Bureau of Mines and Geology.