Southern California is overdue for 'The Big One,' study finds

Southern California is overdue for a major earthquake along the San Andreas fault, according to a landmark study released Friday.

The long-awaited study came after scientists spent years studying the geology of the Carrizo Plain area of the San Andreas, which is about 100 miles northwest of Los Angeles. It found that earthquakes along the San Andreas fault have occurred far more often than previously believed.

"What we know is for the last 700 years, earthquakes on the southern San Andreas fault have been much more frequent than everyone thought," said UC Irvine researcher Sinan Akciz said in a statement. "Data presented here contradict previously published reports."

Added UCI researcher Lisa Grant Ludwig: "People should not stick their heads in the ground. There are storm clouds gathered on the horizon. Does that mean it's definitely going to rain? No, but when you have that many clouds, you think, 'I'm going to take my umbrella with me today.' That's what this research does: It gives us a chance to prepare."

The last massive earthquake on that part of the fault occurred in 1857. But researchers from UC Irvine and Arizona State University found that earthquakes have occurred as often as every 45 to 144 years.

That would make the region overdue for the type of catastrophic quake often referred to as "The Big One."

The finding adds weight to the view of many Southern California seismologists that the San Andreas has been in a quiet period and that a major rupture is possible.

The research, published Friday in the journal Geology, used charcoal samples to look for earthquake activity going back centuries.

-- Rong-Gong Lin II

Updated, 6:21 p.m.: Study shakes up scientists' view of San Andreas fault earthquake risk

Top photo: Evidence of the 1857 Ft. Tejon quake is evident on the side wall of this trench at the Bidart Fan. This area in the Carrizo Plain is one of the easiest places to see movement on the San Andreas Fault. Bottom photo: UC Irvine postdoctoral scholar Sinan Akciz, left, and J. Ramon Arrowsmith, a geologist at Arizona State University, right, are seen in 2009 as they work with Lisa Grant Ludwig on mapping the history of temblors on a portion of the San Andreas Fault. Credit: Ricardo DeAratanha / Los Angeles Times

Comments

[Thotseed]

That's what I have been telling everyone for months it's due this year. Why? Because of the repeat pattern set up starting in the Gulf of California this year at 7.2 followed at shorter and shorter periods between straight line events towards Wrightwood through Mexicali, El Centrol, and most recently near Palm Springs. The next one is due any day in the Riverside area followed by Wrightwood before Thanksgiving. No mistake about this. The pattern is increasingly clear since December of 09' what's going on. Californians would be wise to sell and get out now which almost no one has earth quake insurance so they will lose everything when it pops with about 7.8 to 8.5 force near the El Cajon Pass. Beware Californians!! Your time is near!

[runcatalina]

Time to buy that beach front property in AZ. ;-)

[Terry Turner]

Great article! We do have to stress the importance of being prepared no matter where you live but especially here in California. Anyone who does not have a good earthquake kit is hiding their head in the sand and one day that sand is going to shake them out. I have been looking around on the internet for a premade kit and found so many of the kits are the same and not the best quality. I went to this one site www.survivalkitsonline.com and found some great kits and supplies at a great price. Please everyone take it seriously and get prepared! We should have learned our lesson from Katrina. Thank you, Terry

[olthadi]

A San Diego bartender gave me the same information forty years ago.

[MexiChick]

As a LA native and survivor of the San Francisco 89 earthquake all I can say is bring it on!

[donna]

I want to know WHEN it's going to happen. I don't care that we're "over due" for a quake. If you can tell me when it's going to happen, then I'll bring my "umbrella" with me.

[Hulaboi]

great--then it'll be an additional 2 hrs. flying time to reach the "west" coast from Honolulu---just don't send us a tsunami!

[larry]

much rather risk the big one than all the tornadoes and hurricanes and floods in the midwest and east.That dont include four ft of snow and 40 below

[timF]

Or perhaps the southern branch of the San Andreas is being abandoned and the movement is occurring on the San Jacinto and Elsinore fault zones

[Thotseed]

They still are not telling it like it is. The last time the southern most section of the fault slipped was at Wrightwood in December of 1812. It was further north at Fort Tejon that slipped in 1858. So the danger is even more extreme than they are indicating they continue to ignore Wrightwood at their own peril and not being honest with residents of Riverside, Moreno Valley, Ontario, San Bernadino, etc where most of the growth has been. That's where the extreme danger is in the immediate future.

[John]

I think I will stay in Colorado.

[Thotseed]

Stop moderating my comments LA times you are just making things worse for the citizens of LA who are not getting informed fairly by the USGS. Let the citizens make up their own minds from the facts!

[LAME]

BLAH BLAH BLAH. THE'VE BEEN SAYING THE SAME ISH SINCE THE EARLY 80'S

[Mike]

arizona bay!

[Joe]

Great. This should further help property values.

[Bri-Man]

Bring it on!!!!

[Dan]

The Sky Is Falling The Sky Is Falling!

[Realist]

I guess we'd better check to see who's been buying real estate just east of that fault. Probably Donald Trump...

[peecup]

In other news, fire is hot.

[BC]

did these studies also factor in the minor earthquakes that relieve the pressure?

[tom]

We have been "overdue" for the "big one" since I moved here in 1977.

[ZethByrd]

I check the USGS site daily, it looks like instead of one big one, we're getting lots of little ones, 3.5 - 5s. I don't know that we really have a long enough baseline of information. I know the scientists have studied what they can, and are doing the best they can to do predictions, but we really only have earthquake info of strengths and locations and depths back less that 100 years. We have earthquake data, yes, but not with all the measurements. And the little ones were just not recorded the way they are now.

More work is needed, and I'm glad they're looking.

[sam]

It will occur anytime between now and the year 2986

[C.D. Reimer]

The fun thing about California earthquakes is how the East Coast media reports them. A recent LA quake that didn't shake squat got hyped up pretty good as a "Big One" hitting, even though store surveillance videos showed nothing falling off the shelves. A passing truck does more damage than that.

[Kent]

Would a report that did not raise an alarm get any attention? A newspaper has just enough news to fill the pages. The Missouri valley area used to be an active fault/seismic zone but has been quiet for decades. Still, be prepared for any type of emergency; bottled water, canned food, can opener, flashlight with batteries, plans and back-up plans and locations to meet with children and other family members etc. etc..