By Peter Henderson
SAN FRANCISCO |
Mon Mar 14, 2011 9:47pm EDT
SAN FRANCISCO (Reuters) – California will experience unthinkable damage when the next powerful quake strikes, probably within 30 years, even though the state prides itself on being on the leading edge of earthquake science.
Modern skyscrapers built to the state’s now-rigorous building codes might ride out the big jolt that experts say is all but inevitable, but the surviving buildings will tower over a carpet of rubble from older structures that have collapsed.
Hot desert winds could fan fires that quakes inevitably cause, overwhelming fire departments, even as ancient water pipelines burst, engineers and architects say.
Part of the lesson from the disaster that hit Japan on Friday is that no amount of preparation can fully protect a region such as California that sits on top of fault lines.
Even so, critics fear the state may have long skimped on retrofitting older buildings. Yet the cost of cleaning up after a big quake is likely to be much higher than the cost of even the most expensive prevention, they warn.
“Everybody is playing a gamble that something like this won’t happen,” said Dana Buntrock, associate professor of architecture, at the University of California, Berkeley.
Buntrock, like many others, sees California’s past as a present danger. The university is spending more than $300 million to retrofit and renovate its ancient sports stadium, tucked into the hills overlooking the bay.
“There are places where two walls that were aligned in the 1920s have moved a half meter apart,” she said.
But the steps that the school is taking are not as common in California as the overwhelming risks might suggest.
The concrete high-rises that rose in the years after the 1906 San Francisco earthquake were made without adequate reinforcing steel, while homes and apartment complexes that are built atop of ground-floor parking lots are among the most vulnerable structures in the state.
Japan’s 8.9 earthquake and the tsunami it unleashed destroyed entire villages and left 10,000 or more dead. That sends shivers up the spines of the engineers and architects who follow California’s strategy to withstand a big quake that experts say will surely hit the state one day.
“The question is not if but when Southern California will be hit by a major earthquake — one so damaging that it will permanently change lives and livelihoods in the region,” according to a 2008 study by the United States Geological Survey study.
It predicted 2,000 deaths and $200 billion in damage from a 7.8 southern California quake on the San Andreas Fault.
Geologists say a big earthquake in California would probably top out at a magnitude 8 as the state’s fault structures are different from Japan’s.
A quake of the 7.8 magnitude in the USGS study would have about 30 times less power than the one that struck Japan.
See the rest here:
