Oct. 16 (Bloomberg) -- Jason Henderson keeps a hatchet and crowbar stashed in a closet of his sixth-floor apartment in San Francisco, so he can pry his way out if an earthquake topples the building.

“It will definitely slump, or cave in on the ground floor,” said Henderson, 37, an assistant professor at San Francisco State University. “If it’s an 8, we’re all doomed.”

Two decades after the magnitude 6.9 Loma Prieta earthquake killed 63 people and caused $7.8 billion in damage, San Francisco still has thousands of buildings that aren’t properly fortified, according to a draft of the city’s Community Action Plan for Seismic Safety released earlier this year.

Infrastructure also is vulnerable: It will take about four more years to complete the $5.49 billion replacement of the eastern span of the San Francisco-Oakland Bay Bridge and the reinforcement of miles of aerial track carrying hundreds of thousands of Bay Area Rapid Transit District train commuters.

“If the earthquake happened today, we would have problems,” said Tom Brocher, 55, chief scientist for the U.S. Geological Survey’s earthquake hazards team. “We still need to do a lot of work for mitigating earthquakes, making our homes and businesses stronger.”

The approaching Loma Prieta anniversary and natural disasters around the world are triggering concern about another earthquake in the San Francisco area, said Laura Adleman, a spokeswoman for the city’s Department of Emergency Management.

Web Site Traffic

Traffic on San Francisco’s earthquake-preparedness Web site, www.72hours.org, rose to 11,200 visits in the week ended Oct. 6, a 45 percent increase from the previous week, she said.

A tsunami hit South Pacific’s Samoan region Sept. 29, and the next day a 7.6-magitude temblor off Indonesia’s Sumatra island leveled homes, mosques and hotels in the coastal city of Padang. It killed 1,100 people, Indonesia’s disaster management agency estimated. Eight days later, a 6.8 earthquake occurred off the South Pacific island of Vanuatu. Seismologists say that activity doesn’t signal an increased risk in California.

“We really don’t think what’s going on over there will be able to trigger anything on this side of the world,” said John Parrish, a state geologist in Sacramento. Most earthquakes occur along the boundaries of tectonic plates, when tension along the fault lines causes a sudden shift, he said.

Some people living in the city that has been hit by six earthquakes of magnitude 6.5 or more since 1812 aren’t reassured.

“Seeing any natural disaster on the news makes me nervous,” said Eileen O’Malley, 35, a resident of San Francisco’s Bernal Heights neighborhood.

Ready for Disaster

She keeps an earthquake preparedness kit in her apartment like the ones sold by Chris McCloy, owner of Disaster Survival Solutions LLC in South San Francisco. Traffic on its Web site has more than doubled this month, he said.

“As soon as an event like that happens, we get a flood of visitors,” McCloy said. “Let’s face it, that event 20 years ago was unbelievably traumatic for many bay area residents, and I think people want to get prepared.”

Loma Prieta struck Oct. 17, 1989, minutes before the scheduled start of the third game of baseball’s World Series at Candlestick Park in San Francisco between the San Francisco Giants and Oakland Athletics. Its epicenter was near Loma Prieta mountain, about 60 miles (90 kilometers) south of San Francisco.

Damage Estimate

The quake caused about $6 billion of property damage and about $1.8 billion in damage to the area’s transportation system, according to the geological survey’s Earthquake Center Web site.

“By the time those shock waves arrived in the bay area, they had attenuated somewhat,” said Molly McArthur, division manager for BART capital projects. “If that same shock wave occurred in our own backyard, there could be a tragically different result.”

The transit agency began work in 2005 on an earthquake safety program scheduled to finish in 2013 that is reinforcing 22 miles of aerial tracks and 18 stations and making improvements to the Transbay Tube that carries trains under the bay, connecting San Francisco to Oakland, McArthur said. Some tube improvements are complete and seven construction projects are under way, she said. BART’s weekday ridership averaged 332,000 people in July, said Luna Salaver, a spokeswoman.

The San Francisco Bay area sits over the San Andreas and Hayward fault lines, according to the U.S. geological agency’s web site.

Hayward’s Danger

The Hayward, stretching south from San Pablo to Fremont, is the most dangerous fault in the region because it’s closer to densely populated areas and hasn’t had a major quake in more than 140 years, said Peggy Hellweg, a research geophysicist at the University of California, Berkeley’s Seismological Laboratory. It runs under Oakland, Berkeley, Hayward and Richmond.

In San Francisco’s Hayes Valley neighborhood, Henderson lives in what’s called a soft-story structure, meaning it has large openings on the first floor. Henderson’s has a parking garage, while others house shops or restaurants on ground level. Soft-story structures typically are wood-framed, have no partitioning walls and are more than 35 years old.

During a strong quake, the lower floor may not be able to support the stiff, heavier floors above, leading the building to shift sideways or collapse, according to the draft report. It says 4,400 soft-story buildings in the city would be at risk in a strong quake.

Retrofit Law

Mayor Gavin Newsom directed the city’s Building Inspection Department to craft a law requiring owners to retrofit soft- story properties. The measure is under consideration by the Board of Supervisors.

Fixes are necessary to prevent $1.5 billion in damage after a temblor of magnitude of 7.2 or more on the San Andreas fault, according to the city report. Such destruction could leave tens of thousands of people homeless for years, it said.

“While the 20th anniversary of Loma Prieta serves as a stark reminder of our region’s vulnerability to earthquakes, it also provides an opportunity to encourage our residents to make emergency preparedness a part of their everyday lives,” Newsom wrote in an e-mail.

The University of California, Berkeley’s Memorial Stadium also faces earthquake-proofing. The Hayward fault runs directly under the 86-year-old football stadium, which holds 72,000 spectators. A $300 million renovation is proposed for completion in 2012.

“The odds of being in Memorial Stadium on one of the five home games when an earthquake hits is slim,” said Greg Glass, a 46-year-old Burbank resident, at a game this month. “If I had to live in Memorial Stadium, I’d be very concerned.”

To contact the reporters responsible for this story: Jeran Wittenstein in San Francisco at jwittenstei1@bloomberg.net.; Ryan Flinn in San Francisco at rflinn@bloomberg.net.

Last Updated: October 16, 2009 03:00 EDT