At least 21 quakes have rattled the East Bay city.

Earthquakes and seismic activity often happen with sudden movements underground with tectonic plates. Seismographs are used by scientists to measure the time, location and strength of an earthquake.

A magnitude 5.2 earthquake, centered about 18 miles southwest of Bakersfield, was felt across a wide swath of Southern California on Tuesday night. Its size rattled nerves but caused no major damage ...

What does “moment magnitude” mean, and how do scientists determine the strength of a rupture in the earth? By Henry Fountain Henry Fountain spent a quarter century covering science for The Times. He ...

A preliminary magnitude-4.3 earthquake and smaller quakes in the San Bernardino area produced shaking Thursday morning that was felt over widespread parts of Southern California. The quake, reported ...

A magnitude 3.9 earthquake struck just outside the city limits of Lake Elsinore on Thursday morning, the latest modest temblor to shake Southern California. Weak shaking may have been felt in areas ...

A 4.7-magnitude earthquake struck near Malibu on Thursday morning, according to the U.S. Geological Survey. The quake happened at 7:28 a.m., with an epicenter 3.5 miles northwest of Malibu. Shaking ...

Often in these weekly Night Sky columns I refer to the magnitude of a star or planet. The concept of magnitude is relatively easy to grasp. Put simply, magnitude indicates an object’s degree of ...