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California tsunami could come with no warning

Tsunami inundation map of Los Angeles. Click through for a larger version. Although Southern California is at little risk of a tsunami like the one that devastated Japan, even smaller waves could be damaging, and they could come without warning.

Unlike Japan, California does not have a subduction zone -- a fault where one plate slides under another in an earthquake -- off its coast. The thrusting motion under the sea was what generated the 40-foot tsunami seen in Japan.

But Southern California could see a significant tsunami caused either by a large  earthquake off Alaska or by undersea landslides spurred by smaller earthquakes off California. Northern California is at greater risk because of the Cascadia subduction zone, which runs along the Pacific Northwest coast.

  Quakes off Alaska and the Pacific Northwest could create 15-foot waves in Southern California and 25-foot tsunamis in the northern part of the state, said California State Geologist John Parrish.

Tsunami inundation map of Long Beach. Click through for a larger version.And tsunamis caused by underwater landslides off Southern California could reach as high as 40 feet, although they would be localized and quick to dissipate, said Costas Synolakis, director of the Tsunami Research Center at USC.

That type of event is only expected to strike once in 2,000 or 3,000 years. But, as has happened in Japan, experts say all predictions may go out the window.

“Mother Nature is notorious for not obeying rules that we make,” Parrish said.

A quake off Alaska in 1964 sent 20-foot waves crashing down on Crescent City, Calif., killing 11 people. The same temblor created surges that tore dozens of boats from their moorings and sunk three in the ports of Los Angeles and Long Beach.

USC researchers estimate that a tsunami created by an offshore quake could cost the region $7 billion to $40 billion from port closures alone.

Crescentcity

A quake off Alaska would give California six to nine hours lead time to clear the beaches before a tsunami struck, Parrish said. A temblor off the California-Oregon border, on the other hand, might give Northern California towns less than half an hour to prepare.

“That’s not very much time," he said, "especially if it’s 2 o’clock in the morning and you’re trying to wake up a whole town of people and get them up the hill.”

A tsunami generated by an offshore quake and underwater landslide might come with virtually no warning. Southern California, unlike Northern California, has no tsunami measuring instruments off its coast because the area is considered to be low risk.

RELATED:

Carrier Ronald Reagan assisting Japanese relief

Radiation hot line open for concerned Californians

Videos show tsunami tossing boats at Catalina harbor

-- Abby Sewell

Maps: Map show potential water inundation during Tsunami in Southern California. Credit: California Department of Conservation. Click on the maps for more detail. Photo: Damage from waves in Crescent City, Calif. Credit: Associated Press

 
Comments () | Archives (51)

What about Orange County? Can you post that one too? Thanks!

Wouldn't this be a warning? Feel really bad for Japan... We have been waiting f0r the "Big One" for many years. Who knows when it will come.

No one, but no one can tell when, where, how hard.. No one..

Orange County is part of Southern California. So I think that was covered, NancyHB.

Yes please include OC..are we in danger at all?

Abby Sewell: If you are the reporter for this story - excellent job!!

You are right. So. Cal does face risks from tsunamis coming from Oregon and Washington (the Cascadia subduction zone), and also local undersea mudslides near our coast. The mudslides are most likely to cause problems at beaches that have deep submarine canyons close to shore. Many of the coastal power plants (coal burning) that operate in California are located near beaches with these submarine canyons. What was very interesting from your article is that the USC researchers are predicting big waves up to 40 feet high from the undersea mudslides. That is much bigger than I was expecting! I wonder if the California lifeguards are aware of this problem, and whether their rescue equipment would be safe from 40-foot waves? They can't rescue many people if their boats are destroyed.

One very big problem that we have in So. Cal is that our tsunami system is essentially "untested" in a real-life event. I think that if the sirens went off, esp. in the middle of the night, few residents would understand what they are supposed to do. I was very impressed by how fast many people in Japana reacted to their tsunami warnings. That quick response saved a lot of lives.

Great job with the reporting - keep it up!
We are too complacent in So. California right now. Most people that I talk to don't even have any emergency water stored at their home.

Pete, Redondo Beach

"Southern California, unlike Northern California, has no tsunami measuring instruments off its coast because the area is considered to be low risk."

Low Risk??? Is there such a thing next to the Pacific Ocean????

And if the funding for NOAA gets cut like they plan to do in the budget, we won't even have maps like this to even give us a chance to guess if one's coming.

I'm not sure if it's because the Government feels it's too expensive to protect people from disaster, or if they think it's too expensive to keep us alive afterwards.

People seem to think the Private Business/Charities will be able to swoop in and help - but they will be wiped out by the same disaster than strikes the rest of us, whether its NorCal, SoCal, Hawaii, Alaska.

I can't comprehend why Congress would cut that funding. It boggles my mind, unless it's just that they don't care.

Well, you've got both my house and my business in the red zone on that map. Explains why there are Tsunami warning signs posted on Washington Blvd. and along Culver Blvd. in the 90291 and 90292 areas.

Actually, in the situation of tsunami, different place should be assigned to move in,to mountain area, Earth quake & Tsunami proof tall buildings . The two way Route should be discipline to one way traffic to get away from the sea & people should store at least 30 gallon of gas in reserve. First aid kit, emergency kits

The Tsunami Inundation maps for the rest of california can be found here:

http://www.conservation.ca.gov/cgs/geologic_hazards/Tsunami/Inundation_Maps/Pages/Statewide_Maps.aspx

Please post a link to the source of the innundation maps, so those of us who live near the coast can see what areas we need to evacuate in an emergency. Thanks.

It appears that the Los Angeles Times either:
A) does not want everyone to see the remaining inundation maps.
or
B) is blocking my messages from the last hour.

So, I'll try one more time to help everyone with getting the location of the rest of the maps. You will have to type "http://www" in front of the below information in order to reach the website:

.conservation.ca.gov/cgs/geologic_hazards/Tsunami/Inundation_Maps/Pages/Statewide_Maps.aspx

As far as tsunamis go, you're in greater danger from the fault we have offshore from us up here in the Pacific NW. The Cascadia fault moves about every 300 years producing mega-quakes and mega-tsunamis. It will wipe us out before paying you a visit with a series of big waves. The entire Pacific basin is affected by such earth movements. Country killers.

x

PANIC!!!!!!

The Japanese tsunami makes one think but to speculate on what will happen and when will only cause panic.

Scientist have been predicting the big one since the 1906 San Francisco earthquake.

I experienced the San Fernando (1971), Whittier (1986) and the Northridge (1994) earthquakes and I can tell you when it comes it will come like a thief in the night.

You won't be able to run or hide so the best thing to do is prepare for the black outs, lack of food and water and keep cash in small denominations on hand. A first aid kit and a family emergency plan and a landline would be good. You can call 911 from a landline even if you don't have phone service.

Please revise paragraph #2 to say "Southern..." [California], as those of us living in the subduction zone in Humboldt County still consider ourselves Californians (and are still considered so by the Franchise Tax Board).

I'm selling our family home on Balboa and moving to higher ground as soon as possible! I'm freightened and also want to take a nap.

I hope to God we don't get a tsunami. Any tsunami would be a bad one. It further deteriorate already deteriorate States economy. I don't even think the State is ready for it

All info is important when it comes to safety...But will someone please tell us in plain english.
How many miles inland destruction from the wave if it is 5" or 50".And obviously the distance will be varied according to where it hits .Someone needs to make an official diagram - map and put it online.Maybe even a voice-prompt emergency line .

"FEAR IS disolved by KNOWLEDGE"

This was already predicted

Is there any geologic or historical evidence that this has even happened? In Crescent City, there were old Native American Indian legends of the sky growing dark and a huge wave coming ashore. Wondering if there are any such legends from the Chumash.

God is in control not anyone else, and mother nature can do whatever she wants. Be prepared!

uh i think the bigger fear is "San Onofre"(our nuclear power plant) if that blows then the whole west coast is screwed...

 
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L.A. Now is the Los Angeles Times’ breaking news section for Southern California. It is produced by more than 80 reporters and editors in The Times’ Metro section, reporting from the paper’s downtown Los Angeles headquarters as well as bureaus in Costa Mesa, Long Beach, San Diego, San Francisco, Sacramento, Riverside, Ventura and West Los Angeles.
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