Earthquakes usually occur along fracture zones in Earth's crust, where large tectonic plates slide past one another and become locked. Stress builds up over long periods and is suddenly released in the form of an earthquake.

CONTRA COSTA COUNTY, CA - A 3.5 magnitude quake shook close to Alamo on Sunday morning, the U.S. Geological Survey reported.

The mega-earthquake. It’s coming. We don’t know exactly when or how big it’s going to be, but it’s coming. It will be chaotic, and with millions of lives on the brink, California will be put to the ultimate test.

The National Weather Service said there was no tsunami threat in California or anywhere on the West Coast after a 7.8-magnitude earthquake struck Sunday afternoon in the Philippines.

MENDOCINO COUNTY, CA - A 2.0 magnitude quake struck near Laytonville on Friday morning, according to the U.S. Geological Survey.

A swarm of more than one hundred earthquakes rattled Southern California's Imperial County on Saturday, with the largest reported temblor registering at a magnitude of 4.5, according to the United States Geological Survey.

A magnitude 5.1 earthquake shook off California's northern coast Wednesday morning, according to the U.S. Geological Survey.

A leading insurer has warned that the reinsurance industry may be seriously underestimating earthquake losses because catastrophe models fail to account for a little-known phenomenon known as a

California recorded 64 earthquakes in a single 24-hour period, more than any other state in the country, while the oil-producing regions of Texas registered 29 quakes during the same span. The contrast between the two states raises a pointed question: how much of the shaking in Texas traces back to the underground disposal of oilfield