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Scientist Says San Andreas 'Locked, Loaded And Ready To Roll'

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Fear of The Big One been reverberating after a leading earthquake scientist pronounced the Southern California section of the San Andreas fault "locked, loaded and ready to roll," at an earthquake conference Wednesday.

The L.A. Times reports that Thomas Jordan, director of the Southern California Earthquake Center, warned that the San Andreas fault had been too quiet for too long.

The last time the southern San Andreas truly shook the southland was a mere four months after California had become the 31st state in the Union. When the magnitude 7.9 Fort Tejon quake ruptured halfway across the state in 1857, Franklin Pierce was president, Henry David Thoreau was alive and Horace Greeley was still nearly a decade away from exhorting the nation to Go west young man, and grow up with the country.

"The springs on the San Andreas system have been wound very, very tight. And the southern San Andreas fault, in particular, looks like it's locked, loaded and ready to go," Jordan said in his talk.

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Geological studies have shown that over the past 1,400 to 1,500 years major earthquakes have ruptured the southern San Andreas fault at roughly 150-year intervals (1857 was 159 years ago, fwiw).

We spoke with USGS earthquake geologist Dr. David Schwartz to better understand the concept of a fault being "ready to go."

"We have a very short history in which we've actually observed faults rupture," Schwartz told LAist. He explained that most of our knowledge about earthquakes before the mid-nineteenth century is extrapolated from scientific data and geological dating, meaning that we have limited information, especially for faults with long rupture times.

The reoccurrence times always have an uncertainty to them, with accuracy depending largely on the quality of the data and the how precise the historical dating was. Sometimes seismic events can occur over a shorter interval period and sometimes they take more time, but, as Schwartz said, "all faults will eventually fail."

So, we asked, what's the over/under that we all die in a massive, blazing rupture of the San Andreas fault?

Schwartz said he couldn't answer that question. If there is a large earthquake near L.A., there will certainly be loss of life and significant damage, but, as Schwartz explained, the level of fatalities will depend on a great many variables, including time of day and outside events.

Take for example the 1989 Loma Prieta earthquake in Northern California: that massive quake (also on the San Andreas, but this time the northern section) occurred just after 5 p.m., when freeways would usually be jam-packed with commuters. But it also coincided with the World Series—and not just any World Series, this was the 1989 game between the Oakland Athletics and the San Francisco Giants, meaning two Bay Area teams facing off against each other. Because so many people were watching the game, there were far fewer commuters in transit as transportation structures collapsed.

So is the big one nigh? "I wouldn't bet against it," Schwartz said. "I don't think anyone would."

Related: Thousands Of Apartments Will Need To Be Earthquake Retrofitted Soon
Earthquake Watch: Are we Overdue for 'The Big One'?