According to the USGS, the real threat comes from smaller (about magnitude 7) earthquakes occurring on the Hayward fault, the Peninsula segment of the San Andreas fault, or the Rodgers Creek fault. All of these fault lines are located in the Northern California region of the San Andreas Fault Zone.
ABC7 ORIGINAL SERIES: 'The Earthquake Effect' provides in-depth coverage on Bay Area's readiness for the next major earthquake
The San Andreas Fault Zone is more than one fault line, it's a zone. This zone is made up of a complex collection of smaller fault segments that accommodate the movement between the North American Plate and the Pacific Plate.
Several fault lines transect in the San Francisco Bay Area to make up the Northern California zone. Some significant faults in the region are the Calaveras, Concord-Green Valley, Greenville, Hayward, Mt. Diablo, Rodgers Creek, San Andreas, San Gregorio, and West Napa faults.
Four strong earthquakes (magnitude 6.0 or greater) have occurred in the Bay Area since the mid-1800s.
1868 Hayward earthquake
Oct. 21, 1868, a magnitude 6.3-6.7 earthquake severely shook the San Francisco Bay Area for more than 40 seconds. At the surface, the ground rupture was traced for 20 miles (32 km), from San Leandro to what is now the Warm Springs District in Fremont.
1906 San Francisco earthquake
April 18, 1906, a magnitude 7.8 earthquake severely shook the San Francisco Bay Area for 45 to 60 seconds. The earthquake was felt from southern Oregon to the south of Los Angeles and inland as far as central Nevada.
1989 Loma Prieta earthquake
Oct. 17, 1989, a magnitude 6.9 earthquake severely shook the San Francisco and Monterey Bay regions approximately 15 seconds.
2014 South Napa earthquake
Aug. 24, 2014, a magnitude 6.0 earthquake, the largest in the San Francisco Bay Area in over 25 years, severely shook the Bay Area for 10 to 20 seconds, depending on location.
Zoom in on the map below and compare where you live to the significant faults and where strong earthquakes have struck in the Bay Area.
Take a look at ABC7's in-depth coverage of the Loma Prieta earthquake here.
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