7 California faults that could produce among the most devastating earthquakes
An earthquake fault is a fracture in the ground between two blocks of rock. They allow blocks of rock to move relative to each other, according to the U.S. Geological Survey, and when they move fast, that produces an earthquake. In California, the main tectonic forces driving earthquakes are the Pacific plate moving northwest relative to the North American plate.
Everyone knows about the San Andreas, the massive fault that was responsible for both the great 1906 San Francisco earthquake and the 1989 Loma Prieta quake. A quake from the San Andreas fault also could devastate Southern California — it last happened in 1857. Several disaster movies have tried to depict what would happen, including the 1978 'Superman' movie and the 2015 thriller 'San Andreas' (with plenty of Hollywood fantasy).
Over the last few decades, researchers have learned to better understand how faults work and to better predict the level of damage a major quake could produce. Their goal, scientists say, is to better prepare. Half a century ago, California lawmakers passed rules designed to prevent building right on top of active faults that reach the Earth's surface.
Fractures in the ground can be mysterious. The 1994 Northridge quake occurred on an unknown blind thrust fault that never extended to the surface and hadn't been mapped. The 2014 Napa earthquake also ruptured a fault that hadn't been mapped.
But there are other major known faults capable of producing disastrous temblors that get little attention.
Location: More than 800 miles long, stretching from near the Mexican border in Imperial County, and continuing through the counties of Riverside, San Bernardino, Los Angeles, Kern, San Luis Obispo, Monterey, San Benito, Santa Clara, Santa Cruz, San Mateo, Marin, Sonoma, Mendocino and Humboldt.
Among the cities and communities that the San Andreas travels through are Coachella, Indio, Cathedral City, Palm Springs, Desert Hot Springs, Banning, Yucaipa, Highland, San Bernardino, Wrightwood, Palmdale, Gorman, Frazier Park, San Juan Bautista, Palo Alto, Portola Valley, Woodside, San Bruno, South San Francisco, Pacifica, Daly City and Bodega Bay.
Impact: A magnitude 7.8 earthquake on 300 miles of the southern San Andreas fault — from the Salton Sea (which is southeast of Palm Springs) to Lake Hughes (just west of Lancaster) — could result in 1,800 deaths, among the worst for a natural disaster in U.S. history. It could cause $213 billion in economic losses.
Earthquakes along the San Andreas in 1857 (Southern California) and 1906 (Northern California) probably were each an estimated magnitude 7.9.
Location: The Newport-Inglewood fault runs from the border of Beverly Hills and Los Angeles, through Long Beach to the Orange County coast. This fault caused the 1933 Long Beach quake, a magnitude 6.4. Severe shaking, as defined by the Modified Mercalli Intensity Scale, was felt in places such as Long Beach, Lakewood, Paramount, Bellflower, Hawaiian Gardens, Los Alamitos, Seal Beach and Huntington Beach.
It continues as the Rose Canyon fault just offshore of the San Diego County coast, and comes ashore directly underneath La Jolla and heads into downtown San Diego.
Impact: The 1933 earthquake was Southern California's deadliest in the modern record, leaving nearly 120 dead and causing $40 million in property damage. In the past, this fault has started earthquakes so violent they caused a section of Seal Beach to fall 1.5 to 3 feet in a matter of seconds.
Evidence suggests that earthquakes as large as magnitudes 6.8 to 7.5 have struck the Newport-Inglewood/Rose Canyon fault system. If a magnitude 7.5 earthquake were to rupture on the Newport-Inglewood/Rose Canyon fault system, such a temblor would bring massive damage throughout Southern California — producing 45 times more energy than the 1933 earthquake.
A plausible magnitude 6.9 earthquake along the Rose Canyon fault through the heart of San Diego would threaten the civic and financial center of California's second largest city and the nation's fourth-biggest naval base.
Location: The length of the East Bay from the San Pablo Bay through Richmond, San Pablo, El Cerrito, Kensington, Berkeley, Oakland, San Leandro, Castro Valley, Ashland, Hayward, Union City, Fremont, Milpitas and San José.
Impact: A report by the U.S. Geological Survey estimates that at least 800 people could be killed and 18,000 more injured in a hypothetical magnitude 7 earthquake that ruptures 52 miles of the Hayward fault between Fremont and San Pablo Bay. As many as 2,500 people could need to be rescued from collapsed buildings, and 22,000 people could be trapped in elevators.
Location: The fault runs roughly along or near segments of Sunset Boulevard through Beverly Hills and West Hollywood, parts of Hollywood Boulevard, Hillside Avenue, Franklin Avenue and Yucca Street through Hollywood and continues through Los Feliz as it crosses Interstate 5 en route to the Raymond fault, which starts in Atwater Village.
Impact: This fault is considered dangerous because it runs through many populated areas with older mid-rise and high-rise buildings. It can produce an earthquake as large as a magnitude 7.
Location: The Raymond fault runs from Atwater Village, Glassell Park and Highland Park — at times along York Boulevard and Meridian Street — and then through South Pasadena, Pasadena, San Marino, East Pasadena, Arcadia and Monrovia. The fault crosses multiple freeways, including Interstates 5 and 210, as well as state Routes 2 and 110.
Impact: It can cause an earthquake as large as magnitude 7. It could produce catastrophic damage locally.
Location: The Santa Monica fault runs below Rodeo Drive and the Beverly Hills shopping district, cutting through the so-called Golden Triangle and running between Santa Monica and Wilshire boulevards, according to a state map published in 2018.
The fault roughly follows the path of Santa Monica Boulevard starting around the Westfield Century City mall to the grounds of the Mormon Temple in Westwood, then heads southwest through the Sawtelle neighborhood. As it continues, there are numerous splays of the fault in the city of Santa Monica, before it moves through Pacific Palisades and into the Pacific Ocean, just off the coast of Malibu.
Impact: An earthquake as large as a magnitude 7 is possible. There are many older buildings underneath the Santa Monica fault, and buildings that sit astride it are at risk of complete collapse.
It is also possible that the Santa Monica, Hollywood and Raymond faults could rupture in the same earthquake event.
Location: The Puente Hills thrust fault system never reaches the Earth's surface, and sits underground at an angle — shallowest about a mile south of USC, where it's two miles under the surface, and deepest along the 210 Freeway corridor, where it's about 10 miles deep.
The broad, roughly rectangular area directly on top of the fault system includes downtown Los Angeles, Pico-Union, Westlake, Echo Park, Silver Lake, Historic South-Central as well as Northeast L.A., the Eastside, Glendale, City of Commerce, Pico Rivera, Downey, Norwalk, Santa Fe Springs and La Mirada.
The fault system also underlies a wide swath of the San Gabriel Valley, including Pasadena, South Pasadena, Alhambra, Monterey Park, Rosemead, San Gabriel, San Marino, Temple City, El Monte, West Covina, Hacienda Heights, Rowland Heights, La Habra Heights, La Puente, City of Industry and Walnut. The fault system also underlies part of Orange County, including La Habra and Brea.
Impact: A magnitude 7.5 quake in the Puente Hills thrust fault system could kill 3,000 to 18,000 people, according to the U.S. Geological Survey and Southern California Earthquake Center. The economic loss could be up to $252 billion, which could be the costliest disaster in U.S. history.
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Yahoo
12 hours ago
- Yahoo
Why one of the biggest earthquakes ever recorded caused so little damage
It was one of the largest earthquakes ever recorded, a magnitude 8.8 monster off the eastern coast of Russia. Despite its remote location, the size of the quake immediately brought potential danger of tsunami to a significant swath of the globe, including Japan, Canada and the United States. Tsunami alerts immediately went out, covering millions of people, including the entire U.S. West Coast. But for all its fury, the quake ended up not being a catastrophe. Dangerous waves that rose more than 10 feet never materialized outside of Russia, and even there, officials had no reports of deaths, and damage appeared to be limited. "In this case, we mostly dodged a bullet," said Mike Rademaker, harbormaster for the Crescent City Harbor, a place that saw deadly tsunamis both in 1964 with the Alaska mega-quake and 2011 when the great Japanese quake hit. While those events represent worst-case scenarios, Tuesday's temblor represents a best-case scenario. "With tsunamis, location and directionality is everything," said Nathan Wood, a tsunami scientist with the U.S. Geological Survey. The area near the epicenter off Siberia's Kamchatka Peninsula did see damage, but it was sparsely populated. Video of the town of Severo-Kurilsk, on an island just off the peninsula, showed a building being swept away. But for areas farther out, initial modeling suggests the tsunami's energy was directed into the open Pacific Ocean, roughly between Alaska and Hawaii, and had time to weaken before it hit more populated areas. "It just kind of shot right between the two of those [states]," Wood said. The tsunami "impacted the local community that was right next to the source [earthquake] where it happened," Wood said. "But for everyone else, it kind of just shot right down this empty hallway — in between the Aleutian Islands chain and the Hawaiian Islands — and so there wasn't really a whole lot in its way. "So by the time it got to the West Coast, like California, Oregon, a lot of the energy had been dissipated," Wood said. Russia saw tsunami waves as high as 16 feet, according to news wire reports, but tsunami heights maxed out at 4 feet in Crescent City, 3 feet in Arena Cove in Mendocino County, 2.7 feet at Port San Luis in San Luis Obispo County, 2.6 feet at Point Reyes in Marin County and 1.5 feet in Monterey. The totals were even smaller in Southern California. The highest wave in the U.S. was 5.7 feet in Kahului, Hawaii, on Maui. "It's a relatively good day," state Sen. Mike McGuire, who represents a large swath of the Northern California coast, said Wednesday. The extensive alerts issued after the earthquake struck at 4:25 p.m. Tuesday PDT sparked concern across the Pacific, as scientists raced to forecast how extensive the tsunami could be. A magnitude 8.8 quake ranks as the sixth most powerful earthquake on record in the last 125 years. But by Tuesday evening, the National Tsunami Warning Center's forecasts indicated that Crescent City would see a tsunami that would likely cap out at no more than 5 feet, and with places like San Francisco and Los Angeles harbor at less than 1 foot or so. Dave Snider, the tsunami warning coordinator at the National Tsunami Warning Center in Alaska, said it might be too early to assess how much damage this tsunami did, but "it is true, maybe this one wasn't as bad as it could have been." "If the focus of this tsunami's energy is not pointed right at your coastline, the impacts to you could be pretty limited," Snider said. The magnitude of the earthquake is important, but it's "more about how much of that water moved, and what direction was that energy pointed at the coastline," Snider said. "In this case, it looks like maybe it just wasn't focused at the California coastline with that intensity of other known events." There are other tsunami scenarios that pose far greater risks to California. One involves a near-shore tsunami, such as a magnitude 9 earthquake along the Cascadia subduction zone, just off the coast of California's North Coast, Oregon and Washington. Depending on the strength and location of the quake, life-threatening waves could approach the coastline in as few as 10 minutes, perhaps not even enough time for an emergency alert to be issued, much less arrive on your cellphone. Near-shore tsunami from other offshore earthquakes could result in waves of up to 6 feet above mean sea level at San Francisco's Ocean Beach; 8 feet in Long Beach and the Santa Monica Pier; 9 feet in Malibu and 30 feet on Catalina Island. Read more: An earthquake just off California's coast poses dire tsunami risk for many communities Another worst-case scenario involves a major earthquake in Alaska sending a tsunami to California. Maximum projected distant-source tsunamis could bring waves of 15 feet above mean sea level to the Santa Monica Pier and Marina del Rey and 32 feet at San Francisco's Ocean Beach. Awareness of tsunami alerts has improved over the years in large part thanks to deep ocean pressure sensors that can detect tsunami that are overseen by the National Oceanic and Atmospheric Administration, said Eric Geist, research geophysicist for the USGS. "There were several, fortunately, in operation right off the Kamchatka subduction zone," Geist said. "So we knew, really quick, that a tsunami — and a fairly sizable one — was generated." One of the tragedies of the 2004 Indian Ocean tsunami was a lack of warning. Helping matters is that this week's tsunami hit California when there was a lower tide. The extensive warnings offered California officials another chance to handle a tsunami at a time when experts are urging both the public and government agencies to be more prepared. In December, a tsunami warning from an earthquake about 30 miles from the Humboldt County coast prompted a decidedly uneven response across Northern California. It was the first time the San Francisco Bay Area had ever received a warning of a "near-shore" tsunami with little time to evacuate, and the response demonstrated how the public had little awareness of whether they lived or work in a tsunami hazard zone. In the end, only a tiny tsunami, measured at 5 centimeters, was recorded in December. Even Tuesday night, there were problems. The California Geological Survey recently updated its tsunami hazard map — showing places in California that are at risk of tsunami inundation. The state's website crashed, yet again — a repeat of the website failing during the December 2024 tsunami warning, although this time, media outlets, including The Times, made interactive versions available. But other efforts at preparation against tsunami have borne fruit. In Crescent City, officials noted that the one dock that structurally failed — "H" dock — during Wednesday morning's tsunami actually worked as designed. "'H' dock was engineered as a wave-and-current attenuator with closely spaced pilings, which are specifically designed to disrupt and dissipate tsunami energy before it reaches the Inner Harbor," Rademaker said. "So its sacrificial role in the overall design appears to have functioned as intended, absorbing the brunt of the surge, and helping to protect the more interior docks." Crescent City Harbor was totally destroyed during the 2011 tsunami, and also suffered damage from a 2006 tsunami — events that each took a three-year rebuilding process. The statewide total in damage from the 2011 tsunami was estimated at more than $100 million. One person in 2011 died after being swept into the sea while taking pictures of the tsunami. The Crescent City tsunami in 2011 topped out at 8 feet. The 1964 Alaska earthquake set off a catastrophic tsunami that devastated Crescent City, washing away 29 blocks and killing at least 11 people. Surges reached 21 feet above the average low tide. Sign up for Essential California for news, features and recommendations from the L.A. Times and beyond in your inbox six days a week. This story originally appeared in Los Angeles Times. Solve the daily Crossword
Los Angeles Times
13 hours ago
- Los Angeles Times
Why one of the biggest earthquakes ever recorded caused so little damage
SAN FRANCISCO — It was one of the largest earthquakes ever recorded, a magnitude 8.8 monster off the eastern coast of Russia. Despite its remote location, the size of the quake immediately brought potential danger of tsunami to a significant swath of the globe, including Japan, Canada and the United States. Tsunami alerts immediately went out, covering millions of people, including the entire U.S. West Coast. But for all its fury, the quake ended up not being a catastrophe. Dangerous waves that rose more than 10 feet never materialized outside of Russia, and even there, officials had no reports of deaths, and damage appeared to be limited. 'In this case, we mostly dodged a bullet,' said Mike Rademaker, harbormaster for the Crescent City Harbor, a place that saw deadly tsunamis both in 1964 with the Alaska mega-quake and 2011 when the great Japanese quake hit. While those events represent worst-case scenarios, Tuesday's temblor represents a best-case scenario. 'With tsunamis, location and directionality is everything,' said Nathan Wood, a tsunami scientist with the U.S. Geological Survey. The area near the epicenter off Siberia's Kamchatka Peninsula did see damage, but it was sparsely populated. Video of the town of Severo-Kurilsk, on an island just off the peninsula, showed a building being swept away. But for areas farther out, initial modeling suggests the tsunami's energy was directed into the open Pacific Ocean, roughly between Alaska and Hawaii, and had time to weaken before it hit more populated areas. 'It just kind of shot right between the two of those [states],' Wood said. The tsunami 'impacted the local community that was right next to the source [earthquake] where it happened,' Wood said. 'But for everyone else, it kind of just shot right down this empty hallway — in between the Aleutian Islands chain and the Hawaiian islands — and so there wasn't really a whole lot in its way. 'So by the time it got to the West Coast, like California, Oregon, a lot of the energy had been dissipated,' Wood said. Russia saw tsunami waves as high as 16 feet, according to news wire reports, but tsunami heights maxed out at 4 feet in Crescent City, 3 feet in Arena Cove in Mendocino County, 2.7 feet at Port San Luis in San Luis Obispo County, 2.6 feet at Point Reyes in Marin County and 1.5 feet in Monterey. The totals were even smaller in Southern California. The highest wave in the U.S. was 5.7 feet in Kahului, Hawaii, on Maui. 'It's a relatively good day,' state Sen. Mike McGuire, who represents a large swath of the Northern California coast, said Wednesday. The extensive alerts issued after the earthquake struck at 4:25 p.m. Tuesday PDT sparked concern across the Pacific, as scientists raced to forecast how extensive the tsunami could be. A magnitude 8.8 quake ranks as the sixth most powerful earthquake on record in the past 125 years. But by Tuesday evening, the National Tsunami Warning Center's forecasts indicated that Crescent City would see a tsunami that would likely cap out at no more than 5 feet, and with places like San Francisco and Los Angeles harbor at less than 1 foot or so. Dave Snider, the tsunami warning coordinator at the National Tsunami Warning Center in Alaska, said it might be too early to assess how much damage this tsunami did, but 'it is true, maybe this one wasn't as bad as it could have been.' 'If the focus of this tsunami's energy is not pointed right at your coastline, the impacts to you could be pretty limited,' Snider said. The magnitude of the earthquake is important, but it's 'more about how much of that water moved, and what direction was that energy pointed at the coastline,' Snider said. 'In this case, it looks like maybe it just wasn't focused at the California coastline with that intensity of other known events.' There are other tsunami scenarios that pose far greater risks to California. One involves a near-shore tsunami, such as a magnitude 9 earthquake along the Cascadia subduction zone, just off the coast of California's North Coast, Oregon and Washington. Depending on the strength and location of the quake, life-threatening waves could approach the coastline in as few as 10 minutes, perhaps not even enough time for an emergency alert to be issued, much less arrive on your cellphone. Near-shore tsunami from other offshore earthquakes could result in waves of up to 6 feet above mean sea level at San Francisco's Ocean Beach; 8 feet in Long Beach and the Santa Monica Pier; 9 feet in Malibu and 30 feet on Catalina Island. Another worst case scenario involves a major earthquake in Alaska, sending tsunami to California. Maximum projected distant-source tsunamis could bring waves of 15 feet above mean sea level to the Santa Monica Pier and Marina del Rey and 32 feet at San Francisco's Ocean Beach. Awareness of tsunami alerts has improved over the years in large part to deep ocean pressure senors that can detect tsunami that are overseen by the National Oceanic and Atmospheric Administration, said Eric Geist, research geophysicist for the USGS. 'There were several, fortunately, in operation right off the Kamchatka subduction zone,' Geist said. 'So we knew, really quick, that a tsunami — and a fairly sizable one — was generated.' One of the tragedies of the 2004 Indian Ocean tsunami was a lack of warning. Helping matters is that the tsunami hit California when there was a lower tide. The extensive warnings offered California officials another chance to handle a tsunami at a time when experts are urging both the public and government agencies to be more prepared. In December, a tsunami warning from an earthquake about 30 miles from the Humboldt County coast prompted a decidedly uneven response across Northern California. It was the first time the San Francisco Bay Area had ever received a warning of a 'near-shore' tsunami with little time to evacuate, and the response demonstrated how the public had little awareness of whether they lived or work in a tsunami hazard zone. In the end, only a tiny tsunami, measured at 5 centimeters, was recorded in December. Even Tuesday night, there were problems. The California Geological Survey recently updated its tsunami hazard map — showing places in California that are at risk of tsunami inundation. The state's website crashed, yet again — a repeat of the website failing during the December 2024 tsunami warning, although this time, media outlets, including The Times, made interactive versions available. But other efforts at preparation against tsunami have borne fruit. In Crescent City, officials noted that the one dock that structurally failed — 'H' dock — during Wednesday morning's tsunami actually worked as designed. ''H' dock was engineered as a wave-and-current attenuator with closely spaced pilings, which are specifically designed to disrupt and dissipate tsunami energy before it reaches the Inner Harbor,' Rademaker said. 'So its sacrificial role in the overall design appears to have functioned as intended, absorbing the brunt of the surge, and helping to protect the more interior docks.' The Crescent City harbor was totally destroyed during the 2011 tsunami, and also suffered damage from a 2006 tsunami — events that each took a three-year rebuilding process. The statewide total in damage from the 2011 tsunami was estimated at more than $100 million. One person in 2011 died after being swept into the sea while taking pictures of the tsunami. The Crescent City tsunami in 2011 topped out at 8 feet. The 1964 Alaska earthquake set off a catastrophic tsunami that devastated Crescent City, washing away 29 blocks and killing at least 11 people. Surges reached 21 feet above the average low tide.
15 hours ago
8.8 magnitude earthquake off Russian coast is world's largest since 2011
The massive 8.8 magnitude earthquake that struck off the coast of Russia was also among the world's 10 largest earthquakes since 1990, according to the U.S. Geological Survey.
