The 1906 San Francisco earthquake was a major earthquake which struck the coast of Northern California at 05:12 am Pacific Standard Time on Wednesday, April 18, 1906. With an estimated moment magnitude of 7.9 and a maximum Mercalli intensity of XI (Extreme), it created high-intensity shaking from Eureka on the North Coast to the Salinas Valley, an agricultural region to the south of the San Francisco Bay Area.