California’s Readiness Lags Other Pacific Coast States

California lags behind other Pacific Coast states in preparing for a tsunami, with maps of worst-case flooding finished for only half of the state’s shoreline and Crescent City -- where a killer wave drowned 11 people 40 years ago -- the only town officially declared “tsunami ready” by the federal government.

In Oregon and Washington, blue-and-white tsunami evacuation route signs remind coastal dwellers of the danger of gigantic earthquake-driven waves.

In Hawaii, where tsunamis are the most deadly natural disaster, phone books include evacuation routes.

Neither precaution exists in California.

State emergency managers say they hope to get signs installed coast-wide within a year or two, but some local officials say they don’t see the need because chances are remote that a major wave would ever hit California.

In Los Angeles County, where Marina del Rey is most vulnerable to high waves, evacuation is best left to law enforcement, said Bill Butler, assistant administrator of the county Office of Emergency Management.

“The first thing to know is that a tsunami is not a major threat in Los Angeles County like an earthquake,” he said.

“The evacuation from the tsunami areas would not be a huge problem.”

But other experts say few California beach dwellers know that they should rush to high ground whenever they feel an earthquake strong enough to make standing difficult.

“I think we have a problem,” said Rich Eisner, earthquake and tsunami program director for the state Office of Emergency Services.

“We’re trying to get this message out, and it’s lost in the background of all the [other preparedness] messages we’re trying to get out to people.”

Massive sea waves spawned by a 9.0 earthquake beneath the Indian Ocean on Sunday are estimated to have killed more than 25,000 people along the South Asia coast.

On the California coast, it barely registered, changing wave heights by just a few inches.

A similar disaster is unlikely but still possible along the West Coast, experts say.

An earthquake of magnitude 9.0 in the “Cascadia subduction” that stretches from Humboldt County to British Columbia could produce tsunamis all along the California coast and as far away as China and Japan.

Such a tsunami could bring waves of 27 to 35 feet high crashing to shore for six to eight hours, flooding as far as a quarter-mile inland, depending upon elevation, Eisner said.

Tsunamis triggered by the Indian Ocean earthquake had little effect on the West Coast because many islands and peninsulas between the epicenter and California absorbed the energy, to disastrous effect.

But seismic experts in California knew within half an hour of the earthquake that the tsunami it spawned would not harm the West Coast, said Lori Dengler, a seismologist and historian at Humboldt State, near Eureka.

Unlike the Indian Ocean area, an early warning system protects the Pacific Coast, although Dengler said it is imperfect at best.

Seismologists track earthquakes around the world quickly and accurately, but the West Coast depends upon just six National Oceanic and Atmospheric Administration tsunami monitors in the Pacific to sense a tell-tale change in wave height.

On Monday, only three of those appeared to be transmitting data, Dengler said.

As an entire column of moving water, from the surface to the bottom of the ocean, a tsunami can travel 500 miles per hour across the ocean and slow to 20 mph as it approaches land.

Until the six monitors were installed in 1996, experts could not tell whether an earthquake generated a tsunami, and even now they have trouble knowing whether the monitors are measuring the tail end or strongest part of a tsunami, Dengler said.

Such monitors would not give much warning to Californians in the event of a big earthquake along the Cascadia subduction zone off the North Coast because it is so near the state.

Based on soil samples, scientists believe the fault zone last ruptured in 1700 with an earthquake of roughly 9.0 magnitude, and quakes of such size are most likely every 300 to 500 years.

“The major preparation and planning efforts have been going on on the North Coast because of that,” said Michael Reichle, acting state geologist.

Tsunamis caused by underwater landslides even closer to state shores are also a risk, particularly in Southern California, Eisner said.

In Santa Monica, Santa Barbara, the Palos Verdes Peninsula and elsewhere, a moderate earthquake could cause the continental shelf to slump, triggering a tsunami along 20 miles or so of coast.

“For that event,” Eisner said, “there would be no warning other than the earthquake itself.”

Of the roughly 80 tsunamis recorded in California since the early 1800s, about 30 have been produced by local earthquakes and landslides, none of them significantly destructive, Dengler said.

More monitors would probably improve long-distance tsunami forecasting and give coastal residents time to evacuate, she said.

But to save lives in the face of localized tsunamis would take a combination of public education and preparation.

People need to know what coastal areas could be flooded in the case of a sudden nearby quake and undersea landslide, Dengler said, and they need to know how best to reach high ground.

Using federal money, California five years ago began mapping inundation areas in the event of a worst-case long-distance and localized tsunami, Eisner said.

Targeting the most populated areas first, the Office of Emergency Services has produced such maps for all counties south of San Francisco.

The northern counties should be finished by March, Eisner said.

The pace of mapping is dictated by money.

It costs roughly $50,000 per county, and the state this year got $88,000 from the National Oceanic and Atmospheric Administration Tsunami Hazard Mitigation Program.

Nationwide, funding for that program was cut by Congress this year from $4.3 million to $2.3 million, Eisner said.

“We’ve had very limited resources, and we’ve struggled to get out as much as we can,” he said. “The events of Sept. 11 really diverted interest. We have a lot of competing threats.”

Ideally, Eisner said, counties will use the maps to calculate evacuation routes, and either federal or state money will be found to pay the several hundred dollars it costs to install each tsunami evacuation route sign.

Oregon posted highway signs several years ago after scientific research indicated a greater risk of giant tsunamis in the Cascadia subduction zone than had been anticipated, said Jay Wilson, earthquake and tsunami program coordinator for Oregon Emergency Management.

Signs there indicate when a driver is entering or leaving a “tsunami hazard zone” -- most are along coast-hugging U.S. Highway 101 -- and mark evacuation routes out of towns to higher ground.

Oregon also mapped anticipated inundation areas, distributed the maps on the Internet and to local officials, and required public schools in tsunami “run-up” areas to practice evacuations once a year.

“In some ways,” Wilson said, “once you get all the mapping done and you get the signs in place, you’re just maintaining infrastructure.”