There have been more than 400 tremors recorded in this swarm as of May 11. How unusual is this?

Add Yahoo as a preferred source to see more of our stories on Google. When a rapid succession of earthquakes occurs, like it has in recent weeks, it always brings the same conversation to office water coolers across California: Is the “big one” coming?

About 55 earthquakes a day – 20,000 a year – are recorded by the National Earthquake Information Center. Most are tiny and barely noticed by people living where they happen. But some are strong enough to shake things off walls, cause cracks in ...

The string of moderate earthquakes occurred within hours along a seismically active stretch near the California–Oregon border.

According to reporting based on U.S. Geological Survey data, a magnitude 4.9 earthquake struck Riverside County at 5:56 p.m. local time, centered roughly seven miles from Indio. The quake was shallow, reported at about 1.87 miles deep, and was followed ...