Many of the mountains, and some of the valleys, in Southern California were formed by the San Andreas fault system-the tectonic boundary between the Pacific and North American tectonic plates-which runs to the east of San Diego County from the Gulf of California up through the Salton Sea and into the Los Angeles region. Like all of California, San Diego is earthquake country.What is the Earthquake Risk in San Diego? *The 76% probability of one or more magnitude 7.0 earthquakes striking Northern California is based on a 30-year period, beginning in 2014. See the USGS interactive fault map to learn more about faults in this area Landslides are possible on steep hillsides.
Houses on liquefied soil may settle or even move laterally on gentle slopes. Soils in lowland areas away from major faults may be subject to liquefaction.Very large earthquakes occurring close to the coast could cause damaging levels of ground shaking and tsunami waves.20th, 2022, a magnitude 6.4 quake struck a few miles off the coast of Humboldt County, followed by at least a dozen smaller aftershocks. Scientists report that partial ruptures on the southern half of the Cascadia Seismic Zone (which extends into Northern California) have historically generated earthquakes with magnitude 8 or greater.