An earthquake like the one in Turkey would devastate Southern California
The destruction caused by the 7.8 magnitude earthquake that struck Turkey on Monday is so widespread and intense that it is difficult to comprehend.
But California has seen earthquakes of this magnitude and more — and scientists have spent years developing simulations of how “The Big One” would play out in the Golden State.
Here’s a closer look at the risks from the pages of The Times:
Projection of a huge earthquake in southern California
An earthquake as strong as 8.2 is possible on the southern San Andreas Fault and would cause disaster across southern California simultaneously, with the fault rupturing near the Mexican border into Monterey County.
Such an earthquake would cause massive damage from Palm Springs to San Luis Obispo — and everything in between, experts say.
In 2008, the U.S. Geological Survey and a host of other government agencies and academics released a study called ShakeOut Scenario which told the story of what could happen if a magnitude 7.8 earthquake returned to southern California.
A magnitude 7.8 earthquake would be “so powerful that it would cause widespread damage and consequently affect the lives and livelihoods of all Southern Californians.” A disaster is a disaster that is unleashed when a society is unprepared for the magnitude of the disruption that occurs,” the report states.
Among the impacts, the report found:
- The death toll could be among the worst for a natural disaster in US history: nearly 1,800.
- Los Angeles County could suffer the highest death toll, more than 1,000, followed by Orange County, with more than 350 fatalities.
- Nearly 50,000 could be injured.
- Major highways to Las Vegas and Phoenix that cross the San Andreas Rift would be destroyed.
- Some 500,000 to 1 million people could be displaced from their homes.
- Southern California could be isolated for a while, with the region surrounded by mountains and earthquake faults.
- Major utilities such as gas, electricity, and cell service would likely be severely compromised.
What history tells us
The last California seismic event that reached magnitude 7.8 was the Great San Francisco Earthquake of 1906. In Southern California, a magnitude 7.8 earthquake struck in 1857. (The earthquake earthquake of magnitude 6.7, which occurred on a much smaller fault in the San Fernando Valley, was 45 times weaker than the so-called Ft. Tejon earthquake.)
The last two major earthquakes to hit Los Angeles – the Sylmar earthquake in 1971 and the Northridge earthquake in 1994 – caused destruction and loss of life. But the worst damage was concentrated in relatively small areas and did not interrupt daily life throughout Southern California.
Experts have long warned that a much larger earthquake will eventually occur and the toll will be far greater.
Risk in Northern California
The San Andreas Fault produced the epic 1906 earthquake that destroyed San Francisco.
But the Hayward Fault in the East Bay also poses a major threat, experts say.
A landmark report from the US Geological Survey in 2018 estimated that at least 800 people could be killed and 18,000 others injured in a magnitude 7 earthquake on the Hayward Fault centered beneath Oakland.
Hundreds more could die from fires following an earthquake along the 52-mile fault. More than 400 fires could ignite, burning the equivalent of 52,000 single-family homes, and a lack of water for firefighters caused by bursting old underground pipes could make matters worse, researchers said.
The Hayward Fault is so dangerous because it cuts through some of the most populated parts of the Bay Area, stretching the entire length of East Bay from San Pablo Bay to Berkeley, Oakland, Hayward, Fremont and up in Milpitas.
Despite all the devastation of the 1906 San Francisco earthquake, it was centered off the coast of the Pacific Ocean.
In the earthquake in Turkey, thousands of buildings reportedly collapsed in a wide area stretching from the Syrian cities of Aleppo and Hama to Diyarbakir in Turkey, more than 200 miles to the northeast. A hospital has collapsed in the Mediterranean coastal town of Iskanderoun, according to The Associated Press.
Building standards in California are significantly stricter. Images in Turkey and Syria show countless buildings toppled.
California has worked to improve seismic safety rules for vulnerable buildings.
The ShakeOut scenario focused on unrenovated brick buildings, flimsy concrete buildings, and so-called soft-story apartment buildings. Some cities, including Los Angeles and San Francisco, have pushed for the renovation of these types of structures.
Last year, Los Angeles announced a milestone: More than 8,000 seismically vulnerable buildings were retrofitted across the city at an estimated cost of $1.3 billion. The improvements mark the biggest advance in seismic upgrades in decades, but still leave thousands of buildings vulnerable to damage or even collapse in a catastrophic quake.
Los Angeles Times