A shallow M4.2 earthquake occurred 4 km (2.5 miles) east-southeast of San Ramon, California, at 15:01 UTC on February 2, 2026, as part of an intense earthquake swarm in the East Bay. U.S. Geological Survey data show sustained seismic activity before and after the main event.
Over 40 earthquakes were recorded along the Calaveras fault southeast of San Ramon, California, between November 9 and 10, 2025. The largest event, M3.8, occurred at 09:38 LT (17:38 UTC) on November 9 at a depth of 9.2 km (5.7 miles). Geological and seismic studies show that the Calaveras fault is capable of generating an event in the M6.5 to M7.0 range over long-term timescales.
An earthquake swarm consisting of 64 recorded events has been occurring in the Death Valley region of California since October 24, 2024, with magnitudes ranging from 0.5 to 4.7 and focal depths reaching a maximum of 15.9 km (9.9 miles). The seismic activity is characterized by shallow to mid-crustal depths, typical of intraplate swarms in tectonically active regions.
A series of small earthquakes, including one with a magnitude of 3.6, struck off the coast of Southern California near Catalina Island on October 20 and 21, 2024.
A robust aftershock sequence, currently exceeding 450 earthquakes, continues to shake Kern County in Southern California after M5.2 on August 7, 2024 — the strongest quake to hit the region in three years.
An intense earthquake swarm is taking place near the Salton Sea in Southern California, U.S. on June 5, 2021, starting with M2.2 at 08:05 UTC (01:05 LT). The USGS has registered 285 earthquakes by 21:24 UTC. The swarm is still in progress and new earthquakes are…
An intense earthquake swarm started near Salton Sea, California on September 30, 2020, with 421 earthquakes detected by 07:00 UTC on October 1. The swarm is centered just southeast of Salton Sea, near Westmorland in Imperial Valley, in an area with a history of…
A new seismological study found that a naturally-occurring injection of underground fluids triggered an earthquake swarm near Cahuilla, California, that lasted for nearly four years. The research shows an evolving understanding of how fault architecture drives…
An earthquake swarm is in progress north of Lake Tahoe, California, just west of Reno, Nevada. The sequence started with a shallow M3.7 at 09:02 UTC (02:02 PDT) on June 27, 2017. By 07:21 UTC on June 28, the Nevada Seismological Lab and USGS registered 40…
