Mayor Eric Garcetti’s earthquake adviser warned Wednesday that a high-magnitude earthquake in the Los Angeles area could cause not only loss of life, but potential economic collapse, water shortages, fires and the severing of communication lines.
The city’s buildings and water pipelines are especially vulnerable during an earthquake, which could leave the city without water for months and leave residents without homes or jobs due to buildings being rendered uninhabitable, according to Lucy Jones, the mayor’s science adviser for seismic safety.
Fires that break out following a quake could also lead to further loss of life, Jones said during a presentation to the Los Angeles City Council.
She told the panel it is not enough just to prepare for damages similar to those experienced during the 6.7-magnitude Northridge quake in 1994, saying she has to “keep reminding people that was not a big earthquake.”
While that quake radiated from a fault 10 miles long, the San Andreas fault that is expected to be the epicenter of the next big one is 200 miles in length and would affect a wider area, she said.
The last “big earthquake” experienced by Californians was the magnitude-7.8 temblor in 1906 that destroyed San Francisco, Jones said.
That quake prompted a migration from San Francisco to Los Angeles, which increased the city’s population and made it what it is today, Jones said.
But the reverse could happen if Los Angeles and surrounding areas experience a similar-magnitude quake and there is not enough water and shelter to go around, Jones said.
“Will people give up on Southern California? We hope not. We’re trying to make sure that doesn’t happen,” she said.
Los Angeles would also need to contend with major blows to the local economy, similar to the economic devastation suffered in New Orleans following Hurricane Katrina in 2005, Jones said.
“If we have the same sort of disruption to our city … we could be seeing huge losses that go on for decades,” she said.
Predictions made for a 7.8-magnitude quake, done in preparation for Thursday’s Great ShakeOut earthquake drill, indicate “huge losses from business disruption,” Jones said.
Southern California could also face months without reliable access to water that is safe to use and drink, making it even harder for the local population to want to stick around.
“Let me ask you, how long are you willing to stay if you haven’t had a shower in a month?” she asked.
The city must make improvements to its water infrastructure, including protecting aqueducts that carry 85 percent of Los Angeles’ water supply across the San Andreas fault, Jones said.
“Every one of those aqueducts will break in a big earthquake,” she said.
Hundreds of simultaneous pipeline ruptures, similar to the one that caused tens of thousands of gallons of water to burst out of the ground near UCLA earlier this year, are also likely, she said.
In addition to reinforcing pipelines and aqueducts, one of the best ways to protect against water shortages is to have adequate local sources of water, Jones said.
Projections also show that 300,000 buildings will be damaged in Southern California in a major quake, equating to roughly one of every 16 buildings, she said.
Building damage causes homelessness and injuries, so “we clearly have to deal with our buildings,” Jones said.
But even for those buildings that are retrofitted to withstand collapse, only 50 percent would still be habitable, Jones said. The building codes adopted in 1976 only do enough to prevent buildings from falling down, and do not ensure they remain safe to use, she said.
“Our new buildings are very safe, but they can still cost us a lot of money,” she said.
As for un-retrofitted buildings in Los Angeles, the city still has 10,000 to 20,000 soft-story apartment buildings and 1,500 non-ductile concrete buildings that are not up to code because they were built before seismic safety laws were put in place, Jones said.
She said mandatory building retrofitting programs work better than voluntary ones. A survey of programs throughout the state indicate that 22 percent of buildings are retrofitted in voluntary programs, while 88 percent receive retrofitting in mandatory programs, she said.
Jones said another effect of a major earthquake would be the loss of communication, which is integral to the functioning of a “modern economy.”
Jones said she is working with the mayor on a plan to help prepare the city and region for the next big earthquake and, if implemented, it could prevent significant the losses and fatalities.
“We can’t try to prevent all losses,” she said. “Some things are going to go wrong. Let’s make sure it’s not so many of them that our economic system collapses.”
— City News Service