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.
Scientists at the University of South California (USC) have detected that the earthquakes registered alongside California’s San Andreas Fault occur much deeper than previously understood. The previous knowledge of the fault indicated that earthquakes are…
A new earthquake swarm started beneath the Salton Sea in California on August 10, 2020. The risk of a larger earthquake over the next 7 days is considerably elevated due to the swarm when compared to background levels. The southernmost section of the San Andreas…
In a new study, scientists have warned that the Ridgecrest earthquakes in Southern California in 2019 could increase the chance of a San Andreas Fault earthquake. The probability is higher because the 2019 temblors stressed the Garlock Fault, which links the…
Controversial research argues that quakes made a one-two punch off the United States' west coast at least eight times in the past 3 000 years. For instance, the quake that hit Cascadia fault off the northern California coast triggered a second tremor on the San…
Although magnitude 6 earthquakes occur about every 25 years along the Parkfield Segment of the San Andreas Fault, geophysical data suggest that the seismic slip induced by those magnitude 6 earthquakes alone does not match the long-term slip rates on this part of…
Following a M4.6 earthquake that hit just NE of Gonzales, California on November 13, 2017, the USGS has registered more than 130 aftershocks within the 5 km (3.1 miles) of the epicenter. Although most of those aftershocks weren't felt by the Central Coast, the…
Scientists at the University of California, Riverside have detected spontaneous tectonic tremor – a signature of slow earthquakes deep below the earth’s surface – in the Anza Gap region of the San Jacinto Fault. Tectonic tremors are believed to increase the…
In a new study, USGS geologist Dr. Kate Scharer and her team excavated trenches across the San Andreas Fault – near Frazier Mountain in northeastern Kern County – to investigate the timing of sand, mud, and gravel deposits that were episodically ripped…
New research suggests a devastating mega-earthquake could occur throughout the entire San Andreas fault line in California, yielding far worse consequences than previously assumed. The San Andreas fault, 1 300 km (800 miles) long, was not considered capable of…
