For Many, Ignorance Is Bliss Despite Release of State Quake Hazard Maps

Step inside 335 Marina Blvd. and marvel at the views. Marina Green buzzes with Frisbees across the street; Alcatraz and the Golden Gate Bridge loom just outside the living room windows.

The three-story, four-bedroom Spanish Mediterranean home--complete with Jacuzzi and gazebo--is available for $3.4 million, a price that attracted several interested buyers during a recent open house.

But there’s a catch: The house is perched atop soil known to react like quicksand during an earthquake.

The mines and geology division of the state Department of Conservation recently released detailed maps of San Francisco identifying landslide and liquefaction--or soft-soiled--seismic hazard zones. If property is located in one of these areas, sellers are required by law to disclose that to buyers.

For many home shoppers in San Francisco’s demand-driven market, it’s a risk they’re willing to take--no matter the cost.

“Right now people don’t even think about earthquakes,” says real estate agent Brigitte Johns, who is selling the Marina Boulevard house. “Basically, people do inspections, and they know the soil it’s on.”

On the color-coded map, nearly the entire Marina district is covered in green, indicating mushy soil beneath the surface. During the deadly 6.9-magnitude Loma Prieta quake in 1989, houses shook and smoke belched from fires in the area.

The Marina district, built on landfill, was created for the 1915 Panama Pacific International Exposition.

After San Francisco’s fabled 1906 earthquake, a lagoon was drained and rubble from the fires that burned for four days was dumped into it along with sand. That turned into the site of the exposition and, eventually, the Marina district.

Much of the destruction from the 1989 quake, including the collapse of Oakland’s Cypress Freeway, resulted from liquefaction. Liquefaction occurs when sandy soil becomes saturated by ground water and then is shaken.

“You just kind of put it in the back of your head,” says Julie Berta, former owner of the Marina Boulevard house, who lives a few blocks away.

“Most people who buy places here have enough money that they don’t care,” adds her husband, Peter.

The maps, released in 120 cities, including Oakland, Berkeley and Los Angeles, are not meant to deter people from living in the hazard areas. Instead, they’re a tool for homeowners to use to ensure their houses are reinforced before the next big quake rocks the Bay Area, an event seismologists predict will occur within the next three decades.

“Part of it is if you grow up in California, you grow up with the notion that there are earthquakes and they’re bad and they’re scary,” says Darryl Young, Department of Conservation director. “We remove the fear with the strength of knowledge. They can make their building stronger.”

Building officials advise homeowners living in liquefaction or landslide zones to hire an engineer to analyze the soil beneath the house. After that, most foundations can be retrofitted to withstand sinking, shifting or other movement an earthquake could cause.

Concrete or chemical injections also can be pumped into the ground, creating a sandstone-like substance that helps to fill any uneven gaps.

“Our whole goal is to not let people abuse the information,” Young says. “It would not be very good for remodelers to tell homeowners, ‘Oh, your house is going to slide off the hill and you need to give me $100,000 to fix it.’ ”

An estimated $10,000 to $15,000 will substantially reinforce most homes, Young said. That’s a small price compared with the state’s estimated $56 billion in earthquake losses during the last three decades.

Ed Bortugno, a senior geologist at the state Office of Emergency Services in Oakland, estimated that earthquake losses have been about $6.3 billion during the last 30 years for the nine-county San Francisco Bay Area.

Zan Turner, earthquake-preparedness specialist for San Francisco’s Department of Building Inspection, can punch any address into her computer and instantly determine whether it’s on solid ground.

Even if a house is only a block or two away from a landslide or liquefaction zone, it’s safe as long as a nearby structure sitting on shaky ground doesn’t collapse on top of it, she says.

“I’ve been amazed at how little people want to know,” Turner says. “People have no idea what the level of hazard is. If they’re knowledgeable, they can at least discuss it.”

With the click of a mouse, Turner says, homeowners can view the map. Full-color copies are available for $12, and Turner says she’s impressed by the accuracy of the state’s map. It matches earlier city maps identifying hazard zones and even includes a few new areas.

In addition to the Marina district, liquefaction areas in San Francisco include Ocean Beach, North Beach and South of Market. Twin Peaks is a major landslide area.

City officials say the effects of both can be spotted easily throughout the city. Residents of several buildings in the South of Market area now have to walk downstairs to go inside houses and garages that were at street level before Loma Prieta.

Another visible area is above Laguna Honda lake. Houses were built atop sand dunes there on a hillside overlooking the lake.

“After Loma Prieta, the land slumped down the hill and the houses slumped down with it,” says Lawrence Kornfield, chief building inspector at the city’s Department of Building Inspection. “The houses started to crack and tip a little. The street had cracks, and the telephone lines got tight.”

Although many home shoppers are unfazed by the prospect of buying in a hazard zone, some say they will avoid those areas at all costs.

“I wouldn’t buy in this area,” says Howard Epstein, who was at a Marina district open house strictly for remodeling ideas. “You see how beautiful it is, but if you remember back 10 years ago, it was a whole other ballgame.”

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Map index: https://www.consrv.ca.gov/dmg/shezp/maps.htm