Skip to main content
U.S. flag

An official website of the United States government

M4.4 "Sierra Block" earthquake west of Mammoth Lakes

February 3, 2020

At 10:36:54 PST (18:36:54 UTC on) 1 February, a M4.4 earthquake occurred under McGee Mountain near Toms Place, CA, at a depth of 10 km.

Earthquakes are represented by colored, scaled circles on a shaded relief map of the Long Valley Caldera.
Location of the 1 February 2020 earthquake south of the Long Valley Caldera

This area, sometimes referred to as the "Sierra Block" commonly produces earthquakes in the range of M3 with a M4+ every few years. These earthquakes are generally unrelated to volcanic activity, and the alert level at all Long Valley Volcanic Center volcanoes remains at Normal/Green. The current earthquake poses no immediate hazard, but aftershocks like the M3.1 that occurred shortly after at 10:55:36 PST (18:55:36 UTC) may still occur.

Get Our News

These items are in the RSS feed format (Really Simple Syndication) based on categories such as topics, locations, and more. You can install and RSS reader browser extension, software, or use a third-party service to receive immediate news updates depending on the feed that you have added. If you click the feed links below, they may look strange because they are simply XML code. An RSS reader can easily read this code and push out a notification to you when something new is posted to our site.

Was this page helpful?