U.S. Geological Survey (USGS) — Earthquake Hazards Program

Stories

M 6.9 earthquake strikes off Kamchatka's southern coast near Ozernovskiy

Publisher of the PAGER GREEN alert and ShakeMap for the event

A magnitude 6.9 earthquake struck southern Kamchatka on October 16 at 03:35 UTC, 135 kilometers underground. The Kamchatka branch of Russia's Geophysical Survey put the epicenter at Ksudach volcano, which last erupted in March 1907, and said a new eruption was possible.

Updated Oct 20

San Ramon’s December quake swarm won’t stop: a 3.9 rattles the Tri-Valley again

Built World

As of May 2026: Primary source of quake detection, review, and public risk communication

San Ramon's earthquake swarm won't quit—even for Christmas. A magnitude 3.1 rattled the Tri-Valley on Christmas Eve morning, the latest in a relentless cluster. Since early November, the swarm has delivered more than 300 earthquakes. The biggest jolts came in a chaotic 24-hour stretch: a 4.0 Friday evening, then a 3.9 Saturday night, each followed by smaller aftershocks.

Updated May 15