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Mapping earthquake faults sputters in California

Earthquakes rattle California daily, most of them small shakers that do no damage. State geologists say they need more money to map faults.
Earthquakes rattle California daily, most of them small shakers that do no damage. State geologists say they need more money to map faults.

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Earthquakes tend to get your attention. So when the 6.6 Sylmar earthquake hit the San Fernando Valley in 1971, killing 64 people and causing $550 million in damage, state lawmakers went to work.

Among a flurry of earthquake safety laws, they passed the Alquist-Priolo Act.  It required the state to map active earthquake faults and prohibited building directly on top of them. Over three decades, state geologists mapped more than 500 faults, according to the California Geological Survey. But work nearly stopped in 2003.

"In the last 10 years we probably produced a map or two per year,” State Geologist John Parrish said. About 300 known faults remain unmapped. “At this rate it will take us 300 years to do that."

Parrish blames a dramatic drop in funding for the slowdown. A decade ago, when California faced a $30 billion budget deficit, state lawmakers slashed the CGS’s general fund allocation nearly in half – to less than $4 million dollars.

But crying poor is no excuse for delaying important work, State Assemblyman Mike Gatto said.

“Every department of government could make that statement,” he said.  Gatto, a Democrat who represents the Burbank-Glendale area, said the CGS should have made mapping faults a priority. He posed a question.

“Do these government agencies have a duty to still perform what they are mandated to do with the resources that are available?’” Gatto asked.  “The answer is yes.”

Across California, cities and counties rely heavily on what’s known as Alquist-Priolo maps because of their role in regulating development.

“The Alquist-Priolo maps are especially useful to us because they map the location of faults on a block by block basis,” L.A. City Chief Building Inspector Luke Zamperini said.

Want to build a multi-story structure within 500 feet of a fault that’s been mapped by the state? You’re going to need to hire a geologist to conduct exploratory digging to find any additional faulting, Zamperini said.

This is what the controversy over the Hollywood Millennium project is all about. At a city council meeting over the summer, opponents urged councilmembers to hold off on approving two skyscrapers.

“Wait until the state geological survey’s investigation is complete,” attorney Robert Silverstein said. The council still approved the project, but also asked the developer to conduct more studies. Opponents have also filed lawsuits to stop the project.

Parrish said he understands the importance of the Alquist-Priolo – or AP maps. He also said his office faces competing priorities when it comes to determining earthquake risks.

"The AP map is a zone that is a quarter mile wide. But a liquefaction map may cover hundreds of square miles,” he said. A liquefaction map identifies areas where soil is likely to break down into something like quicksand during an earthquake.

“If you have to make a choice where you spend the money, it's a hard choice to make, but you go with the one that's going to protect the most people from the most hazard," Parrish said.

It’s also easy to forget about the need for mapping earthquake faults, amid more immediate concerns like good public schools. State Senator Alex Padilla of the San Fernando Valley said when the ground doesn’t shake, lawmakers don’t make mapping a priority.

“The more time passes since the last big one, the more we are willing to put earthquake related items a little bit on the back burner,” he said.

What’s left on the front burner all too often doesn’t go much further than public awareness campaigns, assemblyman Gatto said.

“On statewide shakeout day, they go out and they hire consulting firms and they give out little ‘squishies’ with slogans.” he said. “What about more hard science?”

For Parrish, moving beyond PR campaigns means finding more money to map the state’s most dangerous faults.

“We’re optimistic the future, with balanced budgets, will bring back good funding for us,” he said.

This year, the geological survey only had money to work on one map – the map for the Hollywood fault.