Houston offers a grim vision of Los Angeles after catastrophic earthquake
For years, scientists have drawn up terrifying scenarios of widespread destruction and chaos that would come to Southern California when a catastrophic earthquake hits.
Their efforts to warn the public may get an unlikely boost from the unprecedented disaster unfolding in Houston, where Tropical Storm Harvey dumped trillions of gallons of rain across Texas and brought America’s fourth-largest city to its knees.
While epic flooding is different from a powerful temblor, both natural disasters fundamentally alter daily life for months or years.
In recent years, officials have drawn up detailed scenarios of what would happen if a huge quake struck this region, part of a larger campaign to better prepare.
The last two big earthquakes to hit Los Angeles — the 1971 Sylmar quake and 1994 Northridge quake — caused destruction and loss of life. But the worst damage was concentrated in relatively small areas and did not fundamentally bring daily life across all of Southern California to a halt.
Experts have long warned that a significantly larger quake will eventually strike and that the toll will be far greater.
The biggest concern for scientists has been the San Andreas, because that fault has a long history of producing large earthquakes more often than others. The San Andreas is the longest and fastest-moving fault in California — a combination that makes it more capable of producing a catastrophic quake we might see in our lifetime.
A quake as strong as magnitude 8.2 is possible on the southern San Andreas fault and would bring disaster to all of Southern California simultaneously, with the fault rupturing between near the Mexican border to Monterey County.
Such an earthquake would “cause damage in every city” in Southern California, said seismologist Lucy Jones — from Palm Springs to San Luis Obispo and everything in between.
The last California seismic event that reached magnitude 7.8 was the Great San Francisco earthquake of 1906. The last one in Southern California struck in 1857. (The magnitude 6.7 Northridge earthquake, which occurred on a much smaller fault in the San Fernando Valley, was 45 times weaker than the so-called Ft. Tejon quake.)
Back then, the region was sparsely populated. Today, some 23 million people live in eight counties in Southern California that could be hit hard in a southern San Andreas megaquake.
In 2008, the U.S. Geological Survey and a host of other state government agencies and academics published a study called the ShakeOut Scenario that told the story of what could happen if a hypothetical magnitude 7.8 earthquake returned to Southern California.
A 7.8 earthquake is a kind “so powerful that it causes widespread damage and consequently affects lives and livelihoods of all southern Californians. A catastrophe is a disaster that runs amok when a society is not prepared for the amount of disruption that occurs,” the report said.