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Quake fault info a must

Valley Forum

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By Thomas D. Elias

Anyone who has seen the epicenter of a major earthquake following a temblor knows that California’s legal and scientific priorities have lately been seriously skewed.

Now, put these recent events together: First, the state Legislature passes and Gov. Jerry Brown signs a new law to require development of a comprehensive statewide earthquake early warning system. Estimated initial cost will be $80 million.

Next comes a report detailing how the state’s effort to map all its significant earthquake faults has slowed almost to a stop, starting just after the 1971 Sylmar event that destroyed a veterans hospital, among other things. That quake occurred on a fault no one previously knew existed and for 20 years mapping was a priority, with 534 maps published detailing active faults.

But since 1991, reports the Los Angeles Times, just 23 more maps have been drawn, none between 2004 and 2011 because of budget cuts. About 300 more faults must be mapped. Then word arrives that a multi-campus team of University of California scientists, funded by the National Science Foundation, has identified about 1,500 of the most apparently quake-vulnerable buildings in Los Angeles, using public records and a walking survey.

Trouble is, the academics won’t give their list to the mayor because they can’t be sure all buildings on their list are really at risk.

The scientists fear they’ll face lawsuits from building owners if they finger structures that are actually sound – something only an on-site assessment can determine.

The question arising from these three developments: How do you create a comprehensive warning system if you don’t know where all the faults lie? And how do you warn the people most at risk if you don’t know what buildings they’re in?

The legislative sponsor of the warning system, Democratic state Sen. Alex Padilla of Los Angeles, insists that while mapping precise locations of all faults is “very important,” it’s still not crucial to early warnings. “Once energy starts to emanate from the epicenter, waves go out,” the MIT mechanical engineering graduate says.

“Energy moves faster than the actual shaking, so depending on how far you are from the epicenter, you might get between 15 and 60 seconds warning, as they do in Japan. That can be crucial if you’re a surgeon in an operation or a train engineer or in a car going over a bridge.”

Padilla agrees that fixing buildings to cut casualties is critical. The first step in getting information needed to do that must be to immunize the scientists who have pinpointed dangerous buildings. If Los Angeles and other cities are to undertake a retrofitting campaign as thorough as one now authorized in San Francisco, they need that information and they need to be protected from lawsuits.

That can be done by actions of the Legislature and Congress.

It’s hard for anyone who hasn’t seen the power of a major earthquake up close to understand how urgent this problem is.

But action is needed, and the comprehensive warning system should be online within two years. We need to know where quakes might strike and who is most at risk.