Among The Earthquakes Listed, Which One Registered The Highest Richter Magnitude?

List of Notable and Major California Earthquakes

California's Earthquake History

Although earlier earthquakes have been documented—such as significant movement on the southern San Andreas fault all the way back to the 1600s—the earliest reported earthquake in California was on July 28, 1769, noted by members of a Spanish expedition to chart a land route from San Diego to Monterey. Members of the expedition led by Gaspar de Portolá were camped along the Santa Ana River when they felt a strong earthquake.

Based on descriptions of the quake, it was likely a moderate or strong earthquake. Some described the shaking in expedition diaries as violent, occurring over the next several days, suggesting aftershocks. Although the magnitude and epicenter are unclear, by comparing the descriptions with more recent events, the quake may have been similar in strength to the 1933 Long Beach or 1987 Whittier Narrows earthquake.

Jump to Earthquake Terminology and FAQs

Jump to the most Recent Earthquakes in California

Timeline of historical Earthquakes in California

Although most of California's quakes are small in magnitude and cause little or no damage, California experiences more than 100 per day!

Many notable shakers—moderate or major earthquakes in California—have made history and are still remembered and talked about today.

Take a look at noteworthy temblors in our state's recorded history by viewing this California earthquake history timeline.

Earthquake Magnitude Scale

This list of earthquakes in California is marked with colored circles indicating magnitude. Where the specific magnitude scale (e.g., Richter scale [ML] or moment magnitude [Mw]) was noted in the source material, that notation has been included, as well, in the summaries. The scale is as follows:

Magnitude 4.0 to 4.9

Magnitude 5.0 to 5.9

Magnitude 6.0 to 6.9

Magnitude 7.0 and greater

Sort California's Earthquake Timeline (currently sorted by most recent earthquakes)

Antelope Valley

July 8, 2021 | M6.0

On the afternoon of July 8, 2021, at least several dozen earthquakes struck Little Antelope Valley, which is in Inyo National Forest, approximately 20 miles southwest of Smith Valley, Nevada. The quakes were a result of normal faulting and strike slip faults near the Antelope Valley fault, which runs north-south along the Sierra Nevada range front. The largest, a 6.0 magnitude, occurred along the eastern edge of the Sierra Nevada, a major physiographic boundary along the California-Nevada border.

The magnitude 6.0 earthquake was widely felt, with reports as far away as the San Francisco Bay Area and Sacramento in California, and Carson City in Nevada. Aftershocks continued to be felt into the night, with a magnitude 4.5 aftershock reported around 10:30 p.m. Damage from the earthquakes on July 8 was minor and included a rockslide in Coleville and items falling from shelves in nearby stores.

Even quakes that don't cause major damage are a reminder that California is earthquake county, and it's important to be prepared. Learn how personal preparedness and practicing critical steps to safety can help you be ready. And if you own your home, one of the best things to do before the next big earthquake strikes is to strengthen it with a seismic retrofit. Get started at StrengthenMyHouse.com.

What is Your Earthquake Risk?

Westmorland

September 30, 2020 | M4.9

A swarm of hundreds of small earthquakes south of the Salton Sea caused thousands of local people to feel "strong" shaking. The first quake on September 30, striking in the late afternoon, was a M3.0. The largest, a M4.9, struck at 5:31 p.m. The swarm lasted for several days, stabilizing at a low rate by Oct. 3. There were no reports of damage, but the swarm is a reminder to be earthquake ready.

According to USGS, this earthquake swarm is in an area of diffuse seismic activity between the San Andreas fault to the north and the Imperial fault to the south. Past swarms in this area include the 1981 Westmorland swarm, where the highest magnitude was a 5.8, and the 2012 Brawley Storm, which included a M5.4 quake. In August of 2020, a swarm of earthquakes had also struck in the same area, the largest being a magnitude 4.6 at Bombay Beach.

What is Your Earthquake Risk?

South El Monte

September 18, 2020 | M4.5

A magnitude 4.5 earthquake struck in Los Angeles, about 10 miles east of the Los Angeles Civic Center, late at night on September 18. It was widely felt across the region, even as far south as San Diego, and was followed by several aftershocks.

The area is seismically active—this quake was not far from the epicenter of the 1987 Whittier Narrows earthquake, which caused extensive damage. In 2014, the La Habra quake struck along the Puente Hills thrust fault, displacing residents. The thrust fault is considered especially dangerous as it runs along a dense urban area (downtown Los Angeles).

Luckily, there were no reports of serious injuries or damage from this quake, but it's a reminder that when there is shaking, you should practice personal preparedness and Drop, Cover, and Hold On until the shaking stops.

What is Your Earthquake Risk?

Lone Pine

June 24, 2020 | M5.8

After a foreshock with a magnitude of 4.6 two days earlier, on June 24, a magnitude 5.8 earthquake struck about 12 miles southeast of Lone Pine, in Inyo County. People felt the shaking as far away as 350 miles northwest in San Francisco and 230 miles east in Las Vegas. People reported feeling shaking as far as Sacramento and Los Angeles, too. Campers at Mount Whitney were evacuated after a rockslide—which was triggered by the shaking—caused "truck-sized boulders" to fly off the mountain, with one landing on the trailhead. CEA had approximately 150 policyholders in the affected area.

According to the Los Angeles Times, a quake of this magnitude "may cause slight and moderate damage in well-built ordinary structures and considerable damage in poorly built or badly designed structures and may break chimneys." If you own an older home, it is recommended to retrofit it to make it more resistant against shaking. Learn more at StrengthenMyHouse.com.

What is Your Earthquake Risk?

Searles Valley

June 3, 2020 | M5.5

Ridgecrest

July 4, 2019 | M6.4
July 5, 2019 | M7.1

Borrego Springs

June 10, 2016 | M5.2

American Canyon (South Napa)

August 24, 2014 | M6.0

In the early morning of August 24, 2014, a magnitude 6.0 earthquake a few miles northwest of American Canyon caused injuries and damage in Napa County and Solano County. In Napa County, the quake killed one person, injured at least 208 people, and caused severe damage to 150 buildings and moderate damage to more than 1,000 buildings. In Solano County, it injured at least 49 people, caused severe damage to 10 buildings and caused moderate damage to more than 30 buildings

The quake also damaged roads, water mains and gas lines in these counties; disrupted utility services in Sonoma County; and caused fires in Napa County. The total economic loss was estimated at $400 million. This earthquake was felt as far north as Arcata and as far south as Bakersfield. It was also felt in numerous cities in Nevada.

Read more from our Press Release: A Year After South Napa Earthquake, Damage Proves Widespread and Costly

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La Habra

March 28, 2014 | M5.1

Westwood

March 17, 2014 | M4.4

Ferndale

March 9, 2014 | M6.8

Canyondam

May 23, 2013 | M5.7

Brawley

August 26, 2012 | M5.4

El Mayor-Cucapah (Baja CA/Mexico)

April 4, 2010 | M7.2

Eureka

January 9, 2010 | M6.5

Chino Hills

July 29, 2008 | M5.4

A little before noon, on July 29, 2008, a magnitude 5.4 earthquake occurred about five miles northeast of Yorba Linda, shaking buildings in downtown Los Angeles. It was felt as far away as Las Vegas.

While the quake caused no deaths, the shaking was strong enough that Disneyland, Knott's Berry Farm and other amusement parks in the area reportedly evacuated and temporarily closed rides. Notable damage to some structures in the area included buildings at California State University, Fullerton; Placentia's public library; the Nixon Presidential Library and Museum in Yorba Linda; and Chapman University. There also were minor injuries, power outages and transit disruptions, and a fire began in a movie theater in Santa Ana as a result of a damaged light fixture.

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Alum Rock

October 30, 2007 | M5.6

Parkfield

September 28, 2004 | M6.0

San Simeon

December 22, 2003 | M6.5

West Hollywood

September 9, 2001 | M4.2

Portola

August 10, 2001 | M5.5

Yountville

September 3, 2000 | M5.0

A magnitude 5.0 earthquake struck in the Yountville (Napa) area in the middle of the night on September 3, 2000. It was felt in many parts of Northern California, including the Bay Area, the Sacramento area and Santa Rosa. It caused one death and more than 40 injuries, including the critical injury of a young boy who was hurt by falling fireplace bricks.

The quake occurred on a previously unknown fault. Damage was estimated at $65 million, with 2,000 houses needing chimney repair.

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Hector Mine

October 16, 1999 | M7.1

Redding

November 26, 1998 | M5.2

San Juan Bautista

August 12, 1998 | M5.4

Coso

November 27, 1996 | M5.3

Ridgecrest

August 17, 1995 | M5.4
September 20, 1995 | M5.8

Northridge

January 17, 1994 | M6.7

Landers & Big Bear

June 28, 1992 | M7.3
June 28, 1992 | M6.5

On the early morning of June 28, 1992, a magnitude 7.3 (Mw) earthquake—the largest Southern California earthquake in 40 years—struck, rupturing five different faults! Although its epicenter was in a sparsely populated area, it was said to have been felt throughout the Los Angeles area, Arizona, Nevada, and Idaho.

That same morning, a magnitude 6.5 (Mw) earthquake occurred in Big Bear and was considered to be the largest major aftershock of the Landers quake. This quake caused considerable damage in the Big Bear area, causing a 44-mile-long fault rupture and landslides that blocked and damaged roads in the San Bernardino Mountains.

Between the two quakes, at least 400 people were injured, one child died from a fallen chimney, and two others died of heart attacks.

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Cape Mendocino

April 25, 1992 | M7.2

Joshua Tree

April 22, 1992 | M6.1

On April 22, 1992, a magnitude 6.1 (Mw) earthquake occurred about 11 miles east of Desert Hot Springs, following a 4.6 foreshock. It caused slight to moderate damage in Joshua Tree, Yucca Valley, Desert Hot Springs, Palm Springs and Twentynine Palms. More than 30 people were treated for minor injuries. There were several aftershocks. The quake was felt as far away as San Diego and Santa Barbara, Las Vegas, Nevada, and even Phoenix, Arizona.

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Sierra Madre

June 28, 1991 | M5.8

Loma Prieta (World Series)

October 17, 1989 | M6.9

Whittier Narrows

October 1, 1987 | M5.9

Chalfant Valley

July 21, 1986 | M6.5

On July 21, 1986, a magnitude 6.5 (ML) earthquake struck near the towns of Bishop and Chalfant, injuring two people. The quake fractured ground in some places, caused rockslides and landslides in others, and caused significant property damage.

Damage included broken ceiling tiles, plaster, chimneys, windows and walls at buildings in Bishop, as well as damage to homes and utility lines in Chalfant when mobilehomes were shaken off their supports. The earthquake was felt as far away as Salt Lake City, Utah. Foreshocks had been felt for up to three weeks prior.

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Oceanside

July 13, 1986 | M5.4

North Palm Springs

July 8, 1986 | M5.6

Morgan Hill

April 24, 1984 | M6.2

Coalinga

May 2, 1983 | M6.7

Longtime residents of the Central Valley will remember the Coalinga earthquake of May 2, 1983, which occurred on a previously unknown fault and injured 94 people, mostly from furniture and other items falling or being thrown about, and from people being knocked to the ground from the shaking.

The magnitude 6.7 (ML) earthquake almost completely destroyed the eight-block downtown commercial district of Coalinga.

An assessment by the American Red Cross stated that 309 single-family houses and 33 apartment buildings were almost destroyed; 558 single-family houses, 94 mobilehomes and 39 apartment buildings sustained major damage; and 811 single-family houses, 22 mobilehomes and 70 apartment buildings sustained minor damage.

Read what CEA had to say on the 35^th anniversary of the Coalinga earthquake.

May 2, 1983, a magnitude (ML) 6.7 earthquake occurred about 12 km northeast of the town of Coalinga, approximately halfway between Los Angeles and San Francisco

Failed cornice and exterior walls of a building in the restricted area of heavily damaged downtown Coalinga. May 4, 1983.

Photo credit: U.S. Geological Survey.

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Humboldt

November 8, 1980 | M7.0

On November 8, 1980, a magnitude 7.0 (ML) earthquake, known as the Gorda Basin or Humboldt earthquake, occurred off the coast of Humboldt County. Six people were injured, and aftershocks were felt for days. The earthquake was felt in parts of California, Oregon and Nevada.

Considering the size of the quake, damage was light, although structural damage did occur. Chimneys fell and, in Fields Landing, at least four wood-frame houses were shifted off their foundations, with two falling partly to the ground. Also, Tompkins Hill Road overpass suffered partial collapse, and there were a few minor landslides, areas of liquefaction, and ground cracks.

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Mammoth Lakes

May 25, 1980 | M6.0

White Wash

February 25, 1980 | M5.5

Imperial Valley

October 15, 1979 | M6.4

Coyote Lake

August 6, 1979 | M5.7

A magnitude 5.7 earthquake on August 6, 1979, injured 16 people in the towns of Hollister and Gilroy and caused an estimated $500,000 in property damage in these towns. This included damage to chimneys in older houses, broken glassware in stores, and structural damage to five buildings in the town of Gilroy. For example, in Gilroy, a wall cracked in the City Hall building, and a ceiling caved in inside a room within the Municipal Courthouse. In Hollister, a real estate office's roof caved in, and a department store sustained damage to beams.

The earthquake damaged a fire station at Pacheco Pass, and a nearby lookout station was vacated because of damage, as well. This earthquake was felt near Bakersfield and Sacramento, and at least 312 aftershocks were recorded.

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Santa Barbara

August 13, 1978 | M5.1

Oroville

August 1, 1975 | M5.7

San Fernando

February 9, 1971 | M6.5

On February 9, 1971, a magnitude 6.5 (Mw) earthquake, also called the Sylmar earthquake, struck in the northwestern part of Los Angeles County in the San Gabriel Mountains, just after 6 a.m.

Although the area was sparsely populated, there were 65 deaths, most of which were caused by the collapse of the Veteran's Administration Hospital. More than 2,000 people were injured. Several other hospitals were also damaged, and newly constructed freeway overpasses collapsed. Had the quake struck at a busier time of day, loss of life would have likely been even greater.

A collapsed overpass at the interchange of Interstates 5 (the Golden State Freeway) and 210 (the Foothill Freeway). Seismic shaking, compression and extension along the length of the roadway were responsible for the damage in this image. This view, looking east, shows the overpass, which was completed (although not all segments were yet in service), as well as San Fernando Valley Juvenile Hall at right. Feb 11, 1971.

Photo credit: U.S. Geological Survey.

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Borrego Mountain

April 8, 1968 | M6.5

On April 8, 1968, a magnitude 6.5 (Mw) earthquake occurred about a mile north of Ocotillo Wells, about 40 miles south of Indio. It was felt as far away as the Yosemite Valley, Fresno and Las Vegas, and it caused damage across much of Southern California: power lines severed in San Diego County, collapsed ceilings in the Imperial Valley, cracked plaster in Los Angeles, landslides close to the epicenter, and minor surface rupture that cracked Highway 78.

The earthquake also caused small displacements along the Superstition Hills fault, Imperial fault and Banning-Mission Creek fault, miles from the epicenter.

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Truckee

September 12, 1966 | M5.9

Parkfield

June 27, 1966 | M6.0

Daly City

March 22, 1957 | M5.3
March 23, 1957 | M4.2

Eureka

December 21, 1954 | M6.5

On December 21, 1954, a magnitude 6.5 earthquake occurred near Eureka. The quake caused significant property damage (estimated at more than $2 million), as well as one death and around 50 injuries.

Damage included cracks to government buildings, such as the county courthouse and Eureka's City Hall, as well as damage to concrete and wood-framed buildings in the area, such as cracked chimneys, plaster and windows. Some underground utilities were also damaged, and a water tank collapsed.

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San Jacinto Fault (Arroyo Salada)

March 19, 1954 | M6.4

Kern County

July 21, 1952 | M7.5

The magnitude 7.5 (Mw) earthquake that occurred on July 21, 1952, was the largest earthquake in Southern California in more than 80 years. It was felt over a large area, including in Nevada, San Francisco and San Diego—and even caused damage in these locations.

It caused 12 deaths, 18 injuries and at least $50 million in property damage. At least 20 of this quake's aftershocks were of magnitude 5.0 or greater. Hundreds of buildings in the Kern County area were damaged, and at least 100 buildings had to be torn down as a result of this earthquake. There was extensive damage to a railroad section, and to land used for agriculture and irrigation.

The quake occurred on the White Wolf fault, which was not previously considered a major threat.

Read what CEA had to say on the 65^th anniversary of the Kern County earthquake.

The 1952 Kern County earthquake damaged a section of Southern Pacific Railroad line near the town of Bealville. Note the sharp bend in the track and the landslide covering the track closer to the tunnel's entrance.

Photo credit: U.S. Geological Survey.

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Desert Hot Springs

December 4, 1948 | M6.0

On December 4, 1948, a magnitude 6.0 (Mw) earthquake occurred about five miles east of Desert Hot Springs, north of Palm Springs. Fortunately, no lives were lost. It was felt as far north as Bakersfield, as far west as Catalina Island, as far east as Central Arizona and as far south as Mexico.

In Los Angeles, about 100 miles away from Desert Hot Springs, a 5,800-gallon water tank split open. Water pipes broke in Pasadena and at the University of California, Los Angeles, and a water main broke in San Diego. Walls and buildings cracked in Escondido, Corona and Pasadena.

Landslides and ground cracks occurred closer to the epicenter. In Palm Springs, two people were injured, buildings were damaged or collapsed, and thousands of dollars of merchandise was destroyed when it fell from shelves.

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Manix

April 10, 1947 | M6.5

Fish Creek Mountains

October 21, 1942 | M6.6

On October 21, 1942, an earthquake of magnitude 6.6 (Mw) occurred south of the Salton Sea, about 27 miles west of the town of Brawley and about 60 miles east of San Diego on the southern section of the Coyote Creek fault, in the southernmost section of the San Jacinto fault zone. San Diegans felt at least 40 aftershocks in the week following the initial earthquake.

Because its location was in a relatively unpopulated area, the earthquake caused relatively little damage: rockslides in Carrizo Gorge, which blocked a highway and railroad track; moderate damage in Jacumba Hot Springs, near the Mexico border; and minor damage in Brawley, El Centro, Westmoreland and San Diego.

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Santa Barbara

June 30, 1941 | M5.5

Imperial Valley

May 18, 1940 | M6.9

On May 18, 1940, a magnitude 6.9 (Mw) earthquake struck about five miles north of Calexico, along the Mexico border. It was the strongest earthquake ever recorded to strike in the Imperial Valley and was felt far away, in Los Angeles and even Tucson, Arizona.

It caused at least eight deaths, seriously injured at least 20 people and caused at least $6 million in direct damage (not including lost crops because of irrigation system damage). It caused a water tank to collapse in Imperial, damaged railroad bridges in California and Mexico, displaced roadway and railroad segments in many areas, swayed tall buildings in Los Angeles, collapsed buildings closer to the quake in Brawley and El Centro, and caused extensive damage to irrigation systems.

The Imperial fault had surface rupture of at least 25 miles, most likely much longer.

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Long Beach

March 10, 1933 | M6.4

Around dinnertime on March 10, 1933, a magnitude 6.4 (Mw) earthquake occurred on the Newport-Inglewood fault zone, causing 120 deaths. It is estimated that about two-thirds of these deaths occurred because people ran out of buildings and were hit by falling debris. There were also more than 500 injuries reported in Long Beach alone, and the quake caused more than $50 million in property damage, mostly to poorly built structures and unreinforced buildings.

Fatalities would have been even higher if the quake had struck during school hours: 70 schools were destroyed, and 120 were damaged. This earthquake led to the California Legislature enacting the Field Act, which gave the State Division of Architecture authority and responsibility for approving design and supervising construction of public schools. Building codes were also improved.

Since the passage of the Field Act, no school in California has collapsed as a result of a seismic event.

Read what CEA had to say on the 85^th anniversary of the Long Beach earthquake.

East Compton Junior High School, in Compton damaged by the 1933 Long Beach earthquake.

Photo credit: U.S. Geological Survey.

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Eureka

June 6, 1932 | M6.4

On June 6, 1932, the magnitude 6.4 (ML) Eureka earthquake (magnitude 5.9 Mw) occurred near Eureka. A falling chimney killed one person, and the quake caused several injuries and caused significant property damage in Eureka, Arcata, Fields Landing and other nearby towns.

Damage included the shaking down of small houses, fallen and cracked chimneys, broken windows, broken water mains, cracked highways and damaged walls. This earthquake was strong enough to be felt hundreds of miles away, in San Jose, as well as in Oregon and Nevada.

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Lompoc

November 4, 1927 | M7.1

On November 4, 1927, a magnitude 7.1 (ML) earthquake struck about 10 miles offshore from Lompoc. The earthquake also produced a sea-quake, which killed and stunned fish near Point Arguello and shook at least two ships in the area.

On land, the quake caused people to fall to the ground and caused damage—such as broken chimneys, houses shifting on their foundations, collapse of buildings, cracked walls and damage to a railroad bridge—in the coastal town closest to the epicenter.

This earthquake also caused a tsunami up and down the coast, recorded in San Francisco, La Jolla, San Diego and Fort Point.

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Santa Barbara

June 29, 1925 | M6.8

On June 29, 1925, a magnitude 6.8 earthquake occurred near Santa Barbara. Shaking was felt in Paso Robles in San Luis Obispo County in the north, in Santa Ana in Orange County in the south, and to Mojave in Kern County in the east.

The quake killed 13 people and caused property damage estimated at $8 million in Santa Barbara, other coastal towns, and towns within the Santa Ynez Mountains and Santa Maria River valleys. Because portions of Santa Barbara were built on landfill, many structures were demolished. Additionally, this earthquake caused landslides in bluffs adjacent to the ocean, as well as damage to railroad tracks in the area.

Strong aftershocks were felt throughout the month of July 1925.

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North San Jacinto Fault

July 22, 1923 | M6.3

Humboldt

January 22, 1923 | M6.9

San Jacinto

April 21, 1918 | M6.8

On April 21, 1918, a magnitude 6.8 (ML) earthquake occurred near the town of San Jacinto. It was a Sunday, which meant business districts in San Jacinto and nearby Hemet were empty, so the number of fatalities and injuries was lower than it might have been on a weekday, with only a few injuries and one reported death.

This earthquake was felt in Arizona and Baja California, as well. The amount of damage in the business districts was significant, and many large masonry structures collapsed. The quake also caused landslides, which resulted in at least one car accident, and blocked roads, including the road from Hemet to Idyllwild. Near Winchester, two miners were trapped in a mine temporarily. Additionally, the shaking caused cracks in the ground, roads and irrigation canals.

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Imperial Valley

June 22, 1915 | M6.1
June 22, 1915 | M6.3

On June 22, 1915, two separate earthquakes occurred about an hour apart near El Centro. The first, a magnitude 6.1 (ML) earthquake, occurred around 7 p.m. and weakened many structures in the region. The second, a magnitude 6.3 (ML) earthquake occurred around 9 p.m. and caused many of the structures weakened in the first quake to collapse.

The first shock had caused many people to exit buildings and move into the streets, and because many of them had not yet returned to the buildings when the second quake occurred, severe injuries were limited.

However, in Mexicali, Mexico, less than 20 miles south of El Centro, dance halls and gambling halls had been busy before the first quake and continued to operate afterward, so many people returned to them. As a result, six deaths and many injuries occurred in Mexicali when weakened structures collapsed with patrons inside them or when materials inside the structures fell.

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Elsinore

May 15, 1910 | M6.0

San Francisco

April 18, 1906 | M7.9

The magnitude 7.9 (Mw) San Francisco earthquake that occurred on April 18, 1906, is one of California's most famous earthquakes.

It was the result of a rupture on the San Andreas fault that caused strong shaking felt as far north as Eureka and as far south as Salinas. It caused more than 3,000 deaths, approximately 225,000 injuries and $400 million in property damage.

Damage occurred well beyond San Francisco, such as into nearby Santa Cruz, San Benito and Monterey counties, where buildings collapsed, bridges were damaged, and river courses were altered.

Read our press release from the 110-year anniversary of this quake.

The Great 1906 San Francisco earthquake
The earthquake- and fire-wrecked Hibernia Bank Building in San Francisco, following the 1906 earthquake.

Photo credit: U.S. Geological Survey.

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San Jacinto Fault Zone

December 25, 1899 | M6.5

Cajon Pass

July 22, 1899 | M5.7

Vacaville-Winters

April 19, 1892 | M6.4

Laguna Salada

February 23, 1892 | M7.0

Owens Valley

March 26, 1872 | M7.4

Hayward

October 21, 1868 | M6.8

Fort Tejon

January 9, 1857 | M7.9

On January 9, 1857 an earthquake with an approximate magnitude of 7.9 (Mw) ruptured about 75 miles northwest of Bakersfield. Fortunately, our state was still developing, and the area with the strongest earthquake activity was not well populated. Relative to the size of the quake, the loss of life was small: two people died.

Still, the effects of the quake were dramatic: the Kern River current was turned upstream, and the waters of Mokelumne River, the Los Angeles River and Tulare Lake were thrown on their banks—with the latter stranding fish miles away from their lake bed. New springs were formed, cracks appeared in roads, and the mission in Ventura sustained major damage. Damage at Fort Tejon was most severe.

Reports from all around Southern and Central California state that the shaking lasted for at least one minute, with suggestions that it could have lasted up to two or three minutes!

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Santa Barbara Channel

December 21, 1812 | M7.2

On December 21, 1812, a magnitude 7.2 earthquake occurred in the Santa Barbara Channel, believed to have come from a fault under Santa Cruz Island. It damaged or destroyed several missions, damaged the Santa Barbara Presidio, and damaged some Native American villages.

The quake also caused a tsunami, reported as far north as San Francisco and with waves washing inland three blocks in Ventura. One theory is that the tsunami was caused by a nearby submarine landslide triggered by the earthquake.

Aftershocks continued for almost four months.

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San Juan Capistrano (Wrightwood)

December 8, 1812 | M7.5

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California Earthquake Terminology

For more about the science of earthquakes and earthquake terms visit the U.S. Geological Survey's Earthquake Glossary.

Earthquake

The sudden movement of the Earth when two large pieces of the Earth's crust, called tectonic plates, suddenly slip is called an earthquake. The release of pressure causes shock waves to shake and roll on the Earth's surface.

Foreshocks and Aftershocks

Often before and after a large earthquake there will be smaller earthquakes. The quakes that happen before are called foreshocks. The ones that happen after are called aftershocks.

Hypocenter/Focus and Epicenter

The place where the earthquake begins below the surface of the earth is called the hypocenter or focus. The place directly above the focus on the Earth's surface is called the epicenter. The earthquake will be the strongest at the epicenter.

Seismology

Seismology is the study of earthquakes. Scientists who study earthquakes are called seismologists.

Seismic Waves

Earthquake waves travel through and on top of the surface of Earth, causing the shaking and vibrations on the ground. Earthquake waves can move 20 times the speed of sound, causing earthquakes to be felt a long way away from their point of origin.

Faults/Fault Plane/Fault Lines

A fault is a weak point within a tectonic plate where pressure from beneath the Earth's surface can break through and cause shaking in an earthquake. Faults can be as short as a few inches or miles long. An earthquake fault rarely follows a straight line. The major fault types include normal, reverse and strike-slip.

California San Andreas Fault Zone

The San Andreas fault formed about 30 million years ago as the North American plate engulfed nearly all of the Farallon plate. Since then, the North American plate has ground against the Pacific plate at a boundary called a strike-slip fault.

The San Andreas fault is one of the largest faults in the world, running more than 800 miles from the Salton Sea to Cape Mendocino. It carves the state in two. San Diego, Los Angeles and Big Sur are on the Pacific plate. San Francisco, Sacramento and the Sierra Nevada are on the North American plate. The two plates crisscross with dozens of active and passive earthquake faults.

Seismograph and the Richter Scale

Soil Liquefaction

Soil liquefaction is the shaking from an earthquake can cause soil to lose its strength and act like a liquid.

Tectonic Plates

Tectonic plates are large, thin layers of the Earth's crust. They stretch, move, slide and grind against each other. When the Earth's upper mantle become stuck as the plates move past one another, the plates lock together, and pressure builds up. When they finally release, earthquakes occur. Many earthquakes happen on the edges of large sections of tectonic plates.

Tsunami

A giant wave (or series of waves) created by an undersea earthquake, volcanic eruption or landslide.