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Earthquakes in Southern California

Handbook Earthquake Mitigation Southern California

1812 December 8th. Santa Barbara, Ventura & LA Counties: a series of earthquakes hit the area, at the same time, with the New Madrid Quakes occurred in Missouri. Missions, the only buildings at that time, were at least severely damaged, 40 people died.

1857 January 9th. Southern California: strongest earthquake in historic times in the area. Due to the sparse population only 2 deaths are reported

1865 October 1st, 9:15am. Northern California, near Eureka and Fort Humboldt: many buildings were at least damaged.

1872 March 26th. Owens Valley: heavy quake, resulting in more than 20 feet of vertical and horizontal displacement, 60 people died, and many houses in the area were destroyed.

1906 April 18th, 5:13am San Francisco: Magnitude 7.7, large areas of San Francisco were destroyed not only by the earthquake but by the fires that followed, at least 600 people died, property damage estimated at $400 million at that time

1925 June 29th. 6:44am, Santa Barbara: Magnitude 6.3, a large area of the business district of Santa Barbara was destroyed, property damage was estimated to at least $8 million, 13 people died

1933 March 11th. 5:54pm Long Beach: no extensive fires, but poor building construction made this quake one the most destructive with $40 million in damage, 115 people died, school buildings experienced extensive damage. This led the state legislators passed the Field Act. It required public schools to be designed and built earthquake resistent.

1940 May 18th, 8:36pm Imperial Valley: Magnitude 7.1, close to the Mexican border, 80% of the structures were destroyed, 9 people died. Due to the sparse population in that area the damage to people was limited. Indirect damage to crops was substantial, because of disruption in drainage channels and flooding after the quake. Dozens of after shocks

1952 July 21st, 4:52am. Kern County: Magnitude 7.5, property damage $50 million, 12 people died. Because of the very sparse population, damage to property and people were less, but agricultural damage ran into the millions because of failed irrigation systems and crops were lost.

1971 February 9th. San Fernando Valley: 64 people died, $500 million in damages

1980 November 8th. Humboldt County: Magnitude 7.2, 40 miles northwest of Eureka in a remote area, this large earthquake caused only $3 million damage

1983 May 2nd, 4:42pm. Coalinga: Magitude 6.5, more than 200 injuries. In the downtown commercial district of Coalinga 59 of 139 buildings were damaged or destroyed.

1987 October 1st. 7:42am Whittier Narrows: Magnitude 6.1, Epicenter 12 miles east of downtown Los Angeles, $360 million in damage, 120 houses and 1,300 apartment units were destroyed, 100 were injured, 8 people died

1989 October 18th, 5:04pm. Loma Prieta: 62 people died, 3,700 injured, $7 billion in property damage. San Francisco and Oakland were about 60 miles north of the epicenter, but suffered the greatest property damage

1992 June 28th. Big Bear (Magnitude 6.2) and Landers (Magnitude 7.3): The Lander’s epicenter was about 125 miles east of Los Angeles and 25 miles north of Palm Springs. The landmass moved about 15 feet to the right and about 3 feet upward. The quake released twice the energy of the Loma Prieta Earthquake (San Francisco) in 1989. Because of the sparse population in that area, the property damage was less than $100 million, but 400 people were injured. It was one of the strongest earthquakes in California history

1994 January 17th. 4:31am Northridge: 60 people died, $42 billion in expenses (including business losses, unemployment, and worker’s compensation payments). The damage was not because of the magnitude of the earthquake itself, due to the location in a highly developed urban area. More than 10,000 homes were damaged, 200 school buildings were also damaged or destroyed, and 82,000 homes and businesses were without electricity, 50,000 were without water, and 28,000 were without natural gas.

San Luis Obispo county is largely countryside (vineyards, wineries, andc ranches) the midpoint between the metropolitan areas of Los Angeles and San Francisco.

Governor Schwarzenegger declared a local state of emergency and visted the town on Tuesday, December 23.

The fault system remained active. Seismologists believe the quake occurred on the Oceanic fault zone, which runs from north of San Simeon southeast to the Santa Lucia Range on the west side of the San Andreas Fault. There had been more than 100 magnitude-3 or higher aftershocks by Wednesday (December 24) morning. The U.S. Geological Survey announced that the aftershock sequence was likely to continue for months and that there is a 90 percent or greater probability that aftershocks of 5.0 magnitude or greater would follow in the next week.

Two people (Jennifer Myrick, 20, of Atascadero, and Marilyn Zafuto, 55, of Paso Robles) were found dead on the street crushed by bricks from the collapse of the entire second floor of the 1892 clock tower Mastagni building; about 50 others in the area sustained minor injuries.

Nevertheless, in two hundred years of recorded california history, there have been fewer than 6,000 deaths due to earthquakes.