California is riddled with geological fault lines, which render the U.S. state on the West Coast susceptible to earthquakes. In this report from San Francisco, VOA's Mike O'Sullivan looks at the risks of a major quake and the precautions officials are taking to minimize the damage.
The violent shaking and destruction have happened here before: in San Francisco in 1906, Long Beach in 1933, just south of San Francisco in 1989, and in the Los Angeles suburb of Northridge five years later.
Steve Walter of the US Geological Survey in Menlo Park, California, says another big quake will surely come. They only question is when. The scientist helped prepare a guidebook urging Californians to take precautions in advance of the next big earthquake. He says they can survive it.
"But you have to take steps - prepare your house, prepare your family, prepare an emergency kit that will get you through those hours and days following the big earthquake," he said.
Precautions can be as simple as bolting big pieces of furniture to the wall, or as elaborate as reconstructing a building to enhance its earthquake safety.
The scientist says it is also important to have an emergency plan, especially for children.
The wife of California governor Arnold Schwarzenegger, Maria Shriver, stopped by a Los Angeles elementary school recently to talk about earthquake safety. She handed each child a backpack with disaster supplies.
"That's a blanket, these are flares, OK," she said. "Take all this home…."
Henry Renteria, director of the governor's office of emergency services, says he is confident Californians can deal with any disaster.
"There's always room for improvement," he said. "But we're also a very disaster-prone state. We'd had experience with fires, with floods, with windstorms, earthquakes. So those types of events have caused us to ramp up our plans and be better prepared."
Others are less confident that the state is ready for what is called the "big one." San Francisco activist and writer James Dalessandro, author of 1906: A Novel, says his city is better prepared than it was when a massive quake destroyed much of the city center nearly a century ago.
He says the 1906 earthquake, estimated at magnitude 7.8 or higher, tore of path of destruction through 500 kilometers of Northern California.
"Upon that land in 1906 were 700,000 people," he said. "Today, you have more than seven million people. You have chemical plants and electric lines and gas lines, and seven million automobiles filled with gas. And you have skyscrapers and bridges and high-rises, things you did not have in 1906 that only make the situation more dangerous."
More than 3,000 people were killed and a quarter million left homeless in the 1906 quake. Today, scientists foresee a 60 percent chance that a large quake of magnitude 6.7 or greater will strike San Francisco in the next 30 years.
California has some of the strictest building codes in the world, but many older buildings remain unsafe, says San Francisco chief building inspector Laurence Kornfield. He says brick buildings, which are susceptible to collapse, are being reinforced, but two other kinds of structures remain potentially dangerous.
"Two other building types that are a particular hazard here are the non-ductile concrete buildings, that is, taller buildings that are concrete that were built before the 1970s," he said. "And that's the kind of building that we saw recently collapse in Pakistan. We have a lot of that kind of building here in San Francisco."
Yet another type of structure, called "soft-story" buildings, also pose a hazard. They are built over a parking garage or have first-floor storefront windows with little support. Structures of this type have toppled in other earthquakes.
The official says wooden buildings can be cheaply strengthened. Older concrete buildings are another matter, and there are hundreds in this city and thousands around the state that risk collapse. Mr. Kornfield says most people in his city are not aware of the danger.
Officials say most structures in California should withstand a major earthquake, and the region is better prepared to cope with a large-scale disaster than most other parts of the world. But scientist Susan Hough, of the U.S. Geological Survey, says even structures built to the strictest standards may not survive a quake undamaged.
"We are prepared for earthquakes, but we haven't been tested by the big one," she said. "And the history is that there have been surprises when earthquakes do happen. Buildings that were thought to be safe are damaged or even collapse."
In most parts of California, officials conduct emergency drills to get ready for surprises when the "big one" comes.