California's Mammoth Lakes area experienced more than 150 small earthquakes over past week

Gary Robbins
The San Diego Union-Tribune
Tue, 11 Jul 2017 02:40 UTC

© USGS

More than 150 tiny and small earthquakes have occurred near Mammoth Lakes since July 3.

The historically restless Mammoth Lakes area has experienced more than 150 tiny and small earthquakes over the past week, including a magnitude 3.0 temblor that hit at 7:13 p.m. on Monday, says the USGS.

The series — which included a 3. 9 quake on Sunday — may be tied to the movement of magma in the nearby Long Valley caldera, said Susan Hough, a USGS seismologist.

"Adjustments to the the crust occur all of the time in that area," said Hough, who is familiar with the many faults that intersect the caldera in California's Eastern Sierra.

A larger swarm occurred in 2014, and didn't result in a major quake. But the region has experienced large temblors, notably in 1980, when two 6.0s and one 6.1 quake occurred within a three day period.