Caltech team mulls quake worst-case scenario
Major quake could cut arteries into city
By Dan Abendschein, Staff Writer Article Launched: 10/08/2008 10:04:45 PM PDT
THE SHAKE UP: Jerry Treiman of the California Geological Society talks about the damage a large earthquake could create. (Eric Reed/Staff Photographer)
CAJON PASS - A 7.8 magnitude quake rips out of the Coachella Valley, heads west along the San Andreas Fault, severs powers lines, cuts a hole in the 15 Freeway, and knocks out rail tracks - leaving Southern California isolated from the rest of the West Coast.
That is the scenario that a group of Caltech geologists will be studying next month as part of an quake drill - the Great Southern California Shakeout - that will simulate how authorities will respond to the massive earthquake they say is likely to hit the region sometime in the next 30 years.
A major focal point of concern is the Cajon Pass, the 4,500-foot saddle between the massive San Bernardino and San Gabriel Mountains, officials said Wednesday.
Speaking from directly on top of the San Andreas fault line in the pass, near an open desert vista crossed by rail lines, power transformers and the nearby freeway, Lucy Jones, the chief scientist at Caltech's earthquake center, laid out what the infrastructure destruction could mean for Los Angeles County.
Power transformers, rail lines, the 15 freeway, oil pipelines and fiber-optic cables all run through the Cajon Pass, one of the few low passes in the mountains to the north and east of Los Angeles County that infrastructure can easily pass through.
The area could be without power for days, or in some cases weeks, Jones said. People on the other side of the pass, in the Victorville area, could be isolated from Los Angeles if the 15 Freeway was breached, she added.
"Most of our lifeline crossings, infrastructure come through the Cajon Pass," said Dale Cox, a government geologist. "And all of them will sever in a quake of that magnitude."
The county's economy could suffer a hit of around $200 billion as shippers struggle to find a way to get goods out of the Long Beach port, said Jones.
The area would not suffer immediate gas shortages, since much of the West Coast's gas is refined in Los Angeles County. But
natural gas pipelines that provide gas to homes would likely be severed, resulting in massive shortages, she added.
Parts of the 210 and 10 freeways in the San Gabriel Valley could also collapse, said Caltrans spokesman Ken Matsuoka. Or, short of that, landslide debris could cover sections of freeway, shutting them down for several days as crews work to clear them out.
Though the worst impact of the quake in the scenario would be to the San Bernardino area, the quake would also cause direct damage to the San Gabriel Valley, knocking down structurally unsound buildings and cutting water pipe lines. Homes would be left without fresh water, said Jones.
Fires caused by the quake would be the biggest concern, she said. "There simply would not be enough firefighters to put out all the fires that were blazing all over the county," said Jones.
The scenario estimates about 53,000 injuries requiring emergency room assistance - far too many for hospitals to handle, she added.
Scientists have also estimated that one in 16 buildings in the county would suffer serious damage in a 7.8 magnitude quake along the San Andreas fault line.
The Cajon Pass scenario, however, is only one possibility: A major quake could rupture along another fault line, although that would mean less damage to the critical Cajon Pass area.
Additionally, the quake could come from the northern direction of the fault line, rather than the Coachella Valley to the south-east of Los Angeles, said Jones.
That quake could have more of an impact on the San Gabriel Valley, though it could be less dangerous to the county as a whole, since it would not hit the Cajon Pass as hard, she said.
The best thing residents can do to prepare, said Jay Alan of the state Office of Homeland Security, is to be prepared to survive on their own for several days. That means having drinking water, food, a fire extinguisher and first aid kit - at minimum, he added.
"Taking care of yourself for 72 hours should be your goal," said Alan. "If you can do that, you will be helping your community and helping first responders by allowing them to deal with people in serious trouble."
To participate in the Great Southern California Shakeout on Nov. 13, go on line and visit www.ShakeOut.org.
dan.abendschein@sgvn.com(626) 962-8811, Ext. 4451
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