Studying Seismic Activity California has 200 or more faults capable of producing large earthquakes. Some of the faults are hidden and some visible at the surface. The biggest concentration of faults are in the San Adreas fault zone and the San Jacinto fault zone. Because of California'...

Understanding the Loma Prieta Earthquake: 10 Years Later At 5:04 PM on October 17, 1989, the San Francisco Bay Area was severely shaken for 15 seconds by the Loma Prieta earthquake located to the south on the San Andreas fault near Santa Cruz. Although the quake did not tear the ground surfac...