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Home > Earthquake Risk > California Earthquakes & Faults by County

California Earthquake Risk Map & Faults By County

500+
Active faults in California
>99%
Chance of a M6.7+ earthquake within the next 30 years
15,700
Known faults in California
30
Most Californians live within 30 miles of an active fault
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Understanding the Risk Where You Live

What are the risks near

?

Select your county from the dropdown menu above, or click on your county on the California map to the left to learn more about California earthquake risk and faults near you.
 
 
North Coast
Likelihood of a M7.0+ striking region in next 30 years
76%
Likelihood of a M7.0+ striking region in next 30 years
Notable zones
Cascadia Subduction Zone & Mendocino Triple Junction
Notable zones
Additional Regional Risk
Tsunamis Along the Coast
Additional Regional Risk
What You Need To Know

North Coast

Del Norte, Humboldt, Lake, Mendocino

  • The Cascadia Subduction Zone stretches underneath the Humboldt-Del Norte county region, starting north of Cape Mendocino.
  • There is a 10 percent probability of a magnitude 8 or 9 earthquake along this zone in the next 30 years.
  • Very large earthquakes occurring close to the coast could cause damaging levels of ground shaking and tsunami waves.  
  • Soils in lowland areas away from major faults may be subject to liquefaction. Houses on liquefied soil may settle or even move laterally on gentle slopes. Landslides are possible on steep hillsides. 
Shasta Cascade
Likelihood of earthquake event
76%
Likelihood of a M7.0+ striking region in next 30 years
Notable faults
Cleveland Hills & Sierra Nevada
Notable faults
Proximity To An Active Fault
Within 20 Miles
Proximity To An Active Fault
What You Need To Know

Shasta Cascade

Butte, Glenn, Lassen, Modoc, Plumas, Shasta, Sierra, Siskiyou, Tehama, Trinity 

  • The Trinity Mountains, Modoc Plateau, Shasta and Lassen peaks were created by geologic forces that are still shaping the landscape. In addition to volcanoes, this is also earthquake country.
  • The Modoc Plateau has both active volcanoes and faults. 
  • Much of the north-eastern part of the state is actively stretching apart, creating numerous faults, all capable of producing earthquakes. 
  • Very large earthquakes that occur closer to the Northern California coast could cause damaging levels of ground shaking here too. Even moderate shaking can damage seismically-vulnerable structures and trigger landslides that could quickly block roads and highways. 
  • Soils in lowland areas away from major faults may be subject to liquefaction. Houses on liquefied soil may settle or even move laterally on gentle slopes. Landslides are possible on steep hillsides. 
Greater Bay Area
Likelihood of earthquake event
76%
Likelihood of a M7.0+ striking region in next 30 years
Cracked Surface Zone Icon
San Andreas & Hayward
Notable faults
Proximity To A Major Fault
Less Than 10 Miles
Proximity To A Major Fault
What You Need To Know

Greater Bay Area

Alameda, Contra Costa, Marin, Napa, San Francisco, San Mateo, Santa Clara, Solano, Sonoma

  • The greater San Francisco Bay Area has a high likelihood of future damaging earthquakes as it straddles the San Andreas fault system—the major geologic boundary between the North American and Pacific tectonic plates. 
  • The main trace of the San Andreas fault runs through much of the State of California, including the Santa Cruz Mountains and up the San Francisco Peninsula, before heading offshore at Daly City and returning onshore again at Bolinas and continuing up the Marin and Sonoma County coasts. 
  • The Calaveras and Hayward faults extend up the east side of the San Francisco Bay. These and several other major faults in the region are part of the San Andreas fault system and can cause damaging earthquakes, like the 1989 Loma Prieta earthquake. 
  • Scientists say there’s a 51 percent chance that the San Francisco region specifically will experience a magnitude-7.0 earthquake within the next 30 years. They also say there’s a 98 percent chance of a magnitude-6.0 quake occurring in the San Francisco area during the next 30 years. 
  • Soils in lowland areas away from major faults may be subject to liquefaction. Houses on liquefied soil may settle or even move laterally on gentle slopes. Landslides are possible on steep hillsides. 
Delta Sierra
Likelihood of a M7.0+ striking region in next 30 years
76%
Likelihood of a M7.0+ striking region in next 30 years
Notable faults and zone
Cleveland Hills and Sierra Nevada faults & San Joaquin fault zone
Notable faults and zone
Additional Regional Risk
Landslides, Liquefaction, Or Levee Failure
Additional Regional Risk
What You Need To Know

Delta, Sierra and Greater Sacramento Areas

Alpine, Amador, Calaveras, Colusa, El Dorado, Nevada, Placer, Sacramento, San Joaquin, Stanislaus, Sutter, Tuolumne, Yolo, Yuba 

  • The Delta region and the Sierra Nevada are known for natural scenery and historic landmarks, and also could face earthquakes. The mountains and the valley have been shaped by repeated earthquakes on faults in the region. 
  • Moderate earthquakes have occurred in the high Sierra, the foothills and in the Central Valley. These occurred on active faults found in wide zones along the crest of the Sierra Nevada, through Lake Tahoe, along the foothills, and in the western Sacramento Valley. 
  • Large quakes from distant faults such as those in the San Francisco Bay Area or east of the Sierra Nevada can also cause significant damage to homes, businesses, and communities, especially in areas where water levels are high in soft soils that can settle unevenly during shaking. 
  • Soils in lowland areas away from major faults may be subject to liquefaction. Houses on liquefied soil may settle or even move laterally on gentle slopes. Landslides are possible on steep hillsides. 
Central Coast
Likelihood of a M7.0+ striking region in next 30 years
75%
Likelihood of a M7.0+ striking region in next 30 years
Notable faults
San Andreas & San Gregorio
Notable faults
Proximity To An Active Fault
Less Than 15 Miles
Proximity To An Active Fault
What You Need To Know

Central Coast

Monterey, San Benito, San Luis Obispo, Santa Barbara, Santa Cruz

This region has a long history of damaging earthquakes. Large earthquakes will occur along the San Andreas fault system—the major geologic boundary between the North American and Pacific tectonic plates—which passes through much of the State of California. 
  • The main trace of the San Andreas fault runs up through the Carrizo Plain and the Diablo range of the central coast region before shifting slightly westward into the Santa Cruz Mountains as it continues northward. 
  • The San Gregorio fault is another major part of the system. It generally follows the coast, just offshore. These and numerous other faults are capable of damaging earthquakes similar to the 1906 San Francisco and 1989 Loma Prieta earthquakes. 
  • Soils in lowland areas may be subject to liquefaction. Houses on liquefied soil may settle or even move laterally on gentle slopes. Landslides are possible in the mountains and on steep hillsides. 
Central Valley South
Likelihood of a M7.0+ striking region in next 30 years
75%
Likelihood of a M7.0+ striking region in next 30 years
Notable faults and zone
San Andreas and Garlock faults & San Joaquin fault zone
Notable faults and zone
Additional Regional Risk
Landslides, liquefaction, or levee failure
Additional Regional Risk
What You Need To Know

Central Valley South

Fresno, Kern, Kings, Madera, Mariposa, Merced, Tulare 

  • Like all of California, the Central Valley—which is ringed by faults—is earthquake country. Shaking can begin suddenly but have lasting impacts. 
  • The San Andreas fault system is to the west, the Garlock fault is to the south and the faults of the Sierra Nevada are to the east. 
  • The San Andreas fault system is the major geologic boundary between the North American and Pacific tectonic plates and passes through much of the state. It will create the biggest earthquakes—as big as magnitude 8—that will disrupt the whole region. But smaller magnitude earthquakes can also cause damaging levels of ground shaking. 
  • A new study by the U.S. Geological Survey indicates that a portion of the San Andreas fault near Tejon Pass could be overdue for a major earthquake. Earthquakes occur about every hundred years on average, along this section of the fault, with the last major earthquake occurring in 1857: the magnitude 7.9 Fort Tejon quake. 
  • Soils in lowland areas away from major faults may be subject to liquefaction. Houses on liquefied soil may settle or even move laterally on gentle slopes. Landslides are possible on steep hillsides.
Inyo/Mono
Likelihood of a M7.0+ striking region in next 30 years
75%
Likelihood of a M7.0+ striking region in next 30 years
Notable fault and zone
Owens Valley fault & Eastern California shear zone
Notable fault and zone
Proximity To An Active Fault
Less Than 15 Miles
Proximity To An Active Fault
What You Need To Know

Inyo/Mono

Inyo, Mono

  • Like all of California, this is earthquake country! Residents of these counties have experienced shaking from Nevada earthquakes, as well.  
  • The region has been fashioned by tremendous geologic forces, from the incredible steep slope of Mt. Whitney to the vast Owens Valley in Inyo County. 
  • The Eastern California Shear Zone (ECSZ), a region of increased seismic activity, runs from the Gulf of California through the Mojave Desert-Death Valley and into Nevada. It is part of the tectonic boundary between the Pacific and North American plates.  
  • Active faults at the base of the Sierra Nevada mountain range and within the basins to the east have caused damaging earthquakes in the past, such as the 1872 Owens Valley earthquake. 
  • Soils in lowland areas away from major faults may be subject to liquefaction. Houses on liquefied soil may settle or even move laterally on gentle slopes. Landslides are possible on steep hillsides. 
Southern California Coast
Likelihood of a M7.0+ striking region in next 30 years
75%
Likelihood of a M7.0+ striking region in next 30 years
Notable faults
San Andreas & over 100 smaller active faults
Notable faults
Additional Regional Risk
Tsunamis Along the Coast
Additional Regional Risk
What You Need To Know

Southern California Coast

Los Angeles, Ventura, Orange County

  • Many of the mountains, and some of the valleys, in Southern California were formed by movement within the San Andreas fault system—the tectonic boundary between the Pacific and North American tectonic plates. 
  • The San Andreas fault is the primary feature of the system and the longest fault in California, slicing through Los Angeles County along the north side of the San Gabriel Mountains. It can cause powerful earthquakes—as big as magnitude 8. 
  • A new study by the U.S. Geological Survey indicates that a portion of the San Andreas fault in the Grapevine area near the top of the Tejon Pass could be overdue for a major earthquake. According to the research, earthquakes happen in this section of the fault about every hundred years on average, with the last major earthquake occurring in 1857: the magnitude 7.9 Fort Tejon quake. 
  • There are over a hundred smaller active faults in the region that can cause damaging earthquakes like the Northridge earthquake in 1994, such as the Raymond fault, the Santa Monica fault, the Hollywood fault, the Newport-Inglewood fault, and the San Jacinto and Elisnore faults.  
  • Soils in lowland areas away from major faults may be subject to liquefaction. Houses on liquefied soil may settle or even move laterally on gentle slopes. Landslides are possible on steep hillsides. 
Inland Southern California
Likelihood of a M7.0+ striking region in next 30 years
75%
Likelihood of a M7.0+ striking region in next 30 years
Notable faults
San Andreas & San Jacinto
Notable faults
Proximity To An Active Fault
Less than 10 miles
Proximity To An Active Fault
What You Need To Know

Inland Southern California

Imperial, Riverside, San Bernardino

  • Inland Southern California has scenic mountains, valleys, and deserts. Tremendous geologic forces within the San Andreas fault system—the tectonic boundary between the Pacific and North American tectonic plates—created this spectacular landscape and continue today, reminding us often that we live in earthquake country. 
  • The San Andreas fault is the primary feature of the system and the longest fault in California that can cause powerful earthquakes—as big as magnitude 8. 
  • A large part of the region’s population lives within 50 miles of the San Andrea fault and could be exposed to very strong levels of ground shaking in a major earthquake.  
  • Many other faults, such as the San Jacinto fault, create smaller, yet more frequent earthquakes. 
  • Soils in lowland areas away from major faults may be subject to liquefaction. Houses on liquefied soil may settle or even move laterally on gentle slopes. Landslides are possible on steep hillsides. 
San Diego
Likelihood of a M7.0+ striking region in next 30 years
75%
Likelihood of a M7.0+ striking region in next 30 years
Notable faults
Rose Canyon, Elsinore & San Jacinto
Notable faults
Proximity To An Active Fault
Less Than 15 Miles
Proximity To An Active Fault
What You Need To Know

San Diego County

San Diego

  • Like all of California, San Diego is earthquake country. 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. It is the longest fault in California and can cause powerful earthquakes—as big as magnitude 8—that can still generate strong shaking levels in San Diego. 
  • The Rose Canyon fault runs along the coast and beneath downtown San Diego. Geologists say this is the biggest earthquake threat to San Diego, capable of earthquakes of magnitude 6.5 to 6.8.  
  • The Elsinore and San Jacinto faults cut through East County and can also generate moderately-sized but potentially damaging earthquakes. 
  • Soils in lowland areas away from major faults may be subject to liquefaction. Houses on liquefied soil may settle or even move laterally on gentle slopes. Landslides are possible on steep hillsides. 
After a Damaging Earthquake Strikes

Life After a Big Quake

  • Without earthquake insurance, you will be responsible for all costs to repair or rebuild — or to live and eat elsewhere — if an earthquake forces you from your home.
  • Earthquakes will disrupt services like electricity, water and sewer, and communication devices, and may limit access in and out of the region.
  • Government assistance may not be available. If it is, grants will be limited. Loans may not be enough to replace damaged belongings or repair your home, and they must be repaid.
  • Taking steps now will give you confidence that you and your family are prepared to stay safe!

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Recent California Earthquake Activity
M 3.0
42km WNW of Bayview, CA
Time
Monday, December 17, 2018
8:21 PM
Location
40.934°N 124.630°W
Depth
14.82 km ( 9.21 mi )

View Details

M 2.6
8km NE of Coso Junction, CA
Time
Monday, December 17, 2018
10:02 AM
Location
36.094°N 117.882°W
Depth
4.09 km ( 2.54 mi )

View Details

M 2.7
21km SE of Bodie, CA
Time
Monday, December 17, 2018
3:26 AM
Location
38.058°N 118.875°W
Depth
10.7 km ( 6.65 mi )

View Details

M 3.6
42km W of Shoshone, CA
Time
Sunday, December 16, 2018
6:52 PM
Location
35.957°N 116.735°W
Depth
-0.34 km ( -0.21 mi )

View Details

M 2.9
11km SW of Ridgemark, CA
Time
Sunday, December 16, 2018
2:41 AM
Location
36.746°N 121.455°W
Depth
7.3 km ( 4.54 mi )

View Details

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