Chile Quake Offers Tough Lessons For US Coast
Tuesday, April 6, 2010
As the Easter earthquake shook Southern California, the state's disaster management chief was thousands of miles away in Chile, examining what experts say is the best case study yet for how a truly catastrophic earthquake could impact the United States.
Chile and the U.S. Pacific coast have more in common than their geology; they share advanced construction codes, bustling coastal cities, modern skyscrapers and veteran emergency services.
These were all put to the test in Chile, which despite its extensive planning lost 432 lives in the 8.8-magnitude earthquake and resulting tsunami - lessons that California, Oregon and Washington have yet to fully learn despite deep experience with lesser quakes.
They include: Coastal flood maps mean nothing without local enforcement. Hospitals need to not only stay upright but also stay open. Stringent building standards require stringent inspections. And tourists need to be taught about the dangers of tsunamis, which caused the greatest loss of life in Chile, wiping out seaside campgrounds on the last weekend of summer vacation.
"People living there know that when the earth shakes, it's like an alarm going off: Get out. But visitors aren't conditioned like that," said Matthew Bettenhausen, the secretary of California's Emergency Management Agency.
Most of Chile's modern buildings emerged with little more than broken plaster, but there were some spectacular failures among recently built structures. Some experts blame code violations that lax inspections failed to catch.
"It's not enough to have a good law - you have to follow it," says Rodolfo Saragoni, the University of Chile's top seismic engineer.
Chileans who lost their homes are asking how building firms got away with cutting corners.
"I've never made walls this thin for this kind of building," said civil engineer Carolina Astorga, showing the AP the damaged foundations of her 19-story apartment building in Santiago.
She moved in a month before the quake. Now the building is sunken, leaning and uninhabitable.
"They save more rebar, more money and it comes out cheaper for the contractor. But here are the consequences."
Code enforcement in California, as in Chile, falls to local governments. Some are sticklers, but others are essentially "paper building departments, where they're pushing paper but not actually rigorously enforcing building codes," said Fred Turner, a structural engineer with the state's Seismic Safety Commission.
"I'm afraid there are a few jurisdictions in California that are probably not much better," Turner added.
Likewise, the tsunami responsible for most of Chile's death toll was perfectly predictable from official flood maps published on the navy's Web site. But the coastal cities devastated by the waves did nothing to incorporate the charts in public planning.
"At the least, it indicates a profound lack of coordination between institutions," said Hugo Romero, a geographer at the University of Chile. At worst, he said, it may reflect commercial interests overwhelming the public interest.
Chile's landscape is similar to built-up stretches of the California coast, where state and federal officials have worked to make flood maps available, but local authorities don't always pay heed.
Some California cities - Long Beach, Crescent City and Santa Barbara among them - now incorporate tsunami risks in their public planning. "Other jurisdictions just haven't gotten around to doing anything yet," Turner said.
"California is catching up," he added, noting that Oregon and Washington have a fraction of the population exposure along the coast, but have done more to prepare for the next tsunami.
In other respects, the Pacific Northwest is at risk.
Scientists say a nearby coastal fault like Chile's will likely slip within a few decades, releasing a similarly devastating mega-quake. A magnitude-9 quake struck the area in 1700.
Washington's building codes were updated to international seismic standards in recent years, but Chile has shown that great standards on paper do nothing when a city is full of older buildings that were grandfathered in.
University of California at Berkeley's Jack Moehle, who led a team of engineers assessing Chile's damage, takes that lesson from two cities near the epicenter: Chillan was almost entirely rebuilt with stronger buildings after a 1939 quake, and survived this one more or less OK. Nearby Talca was full of earlier architecture -- and devastated.
"To see Chillan versus Talca, it's like day and night," he said.
California's older cities would suffer more like Talca did if a major quake struck them today, Moehle warns.
Hospitals and other key buildings in parts of California could fare even worse than those in Chile, said structural engineer Bill Holmes, who has been examining Chile's hospitals. Many had 72 hours worth of gas and water on site, which proved invaluable in the catastrophe's aftermath.
California's hospitals are not expected to meet that standard until 2030. And one in 10 won't even be safe from collapse by 2015, according to a report prepared for the California Senate's Health Committee in February.
The rare intensity of Chile's earthquake is also teaching engineers about how international seismic standards might be improved.
Chile's temblor included an unexpected amount of vertical shaking in addition to the usual horizontal movement, according to structural engineer Jay Guin, who runs risk modeling for Applied Insurance Research Worldwide.
Both Chile and the U.S. may need to update building codes accordingly - perhaps applying tougher standards to shakier ground, like the volcanic ash under Concepcion or the landfill under parts of San Francisco.
"It acts like Jell-O. You get that extra violent shaking," said Bettenhausen.
Associated Press Writer Eva Vergara contributed to this report.
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