The area around Mammoth Mountain and Mono Lake has been a hotbed of seismological activity for thousands of years and the recent earthquake swarm is not an abnormal event.

At 7:37 a.m. Saturday, April 11, a 5.2 magnitude earthquake hit 15 miles east of Mono Lake near the California/Nevada border and since that time, about 500 earthquakes have occurred in that region along several different faults. They haven't stopped either, with the more recent Tuesday, April 21 at 10:00 p.m. It registered as an M1.4 quake. That was one of 18 aftershocks in 24 hours, the biggest an M4.1.

"There are a lot of history of [earthquake] sequences in that area and it's interesting," said Kenneth Smith, network seismologist with the University of Nevada, Reno. "It's neat to see."

Smith said this recent swarm of earthquakes is similar to a sequence in 2004-2005, but by the time that was over, there were 7,600 quakes. That sequence started with a 5.5 magnitude on September 18, 2004, and it had three earthquakes over M5.0.

The two swarms are not on the same series of faults, but very similar Smith said. "They have the same behavior," he said.

The Mono Lake Basin was formed by the same geologic processes that shaped the Nevada and Eastern Sierra landscape over the past several million years. Part of that basin is where volcanic Mammoth Mountain is located.

Another recent warm that was closer to Lake Tahoe is north of Gardnerville, Nevada. On March 20, 2020, a M4.5 earthquake hit the area with about 20 aftershocks, Smith said.

Legend for photos:

Magnitude 5 purple

Magnitude 4 red larger symbol

Magnitude 3 red smaller symbol

Magnitude less than 3 yellow.