How to find out if you live in an earthquake hot zone

ByRandall Yip KGO logo

Friday, October 18, 2019

Two experts identify where in the Bay Area you are at most risk for major earthquake damage. Here's how you can find out if you live in an earthquake hot zone.

BERKELEY, Calif. (KGO) -- It's no secret we live in earthquake country. But even in the Bay Area, some areas are more at risk for major damage from a large quake than others. Two experts helped us identify the areas most vulnerable to catastrophic damage.

Here's what you need to know to find out if you're in an Earthquake hot zone.

A building in San Francisco's Marina District collapsed like a house of cards in the Loma Prieta earthquake. Something similar happened in 1964 in Japan's Niigata quake. Experts blame damage to buildings in both quakes on liquefaction.

ABC7 Originals Documentary: 'The Earthquake Effect' provides in-depth coverage on Bay Area's readiness for the next major earthquake

"We have the very soft soils combined with a high water table that is known as liquefaction probabilities," said Brad Aagaard of the US Geological Survey in Mountain View.

USGS put out a map with the Bay Area's liquefaction zones in red -- for danger.

The zone starts at San Francisco's Marina District, goes along the Embarcadero and extends to the Airport and parts of Millbrae and Foster City.

In the East Bay, it's the outer portion of Alameda, along the Oakland waterfront as well as the airport.

Extensive damage is predicted for many buildings there in a quake that's a 6.7 magnitude or higher.

"If you have a structure or a house or any building that is built on that, it may tip or fall over," said Horst Rademacher of the Berkeley Seismological Lab.

Rademacher says he's even more concerned about the Hayward Fault which runs from San Pablo Bay to Fremont. It includes the cities of Berkeley, Oakland and Hayward.

Scientists say there's a one in three chance of a quake 6.7 or higher there in the next 24 years.

"I'm not saying there's no hazard due to liquefaction, but if you ask me what has the higher hazard, I would say the densely populated area around the Hayward fault."

But Aagaard of the US Geologicial Survey says liquefaction zones span several faults -- thus increasing the chance for damage. He points back to Loma Prieta.

"In Oakland, we have the Cypress Freeway, where we have strong amplification of the soil. And then we also had a significant amplification and damage within the Marina District," he said.

The California Conservation Corp released this interactive map.

Albert Chan plugged in his address. The pin indicates where his home sits. The darkened areas are the liquefaction zone. "So it's important to have that earthquake insurance then," said Chan.

Robert Sand of Millbrae also discovered he's in a liquidation zone.

"You just have to take that chance," said the lifelong Bay Area resident.

Corey Topper found out she's not in a liquefaction zone, but isn't breathing any easier.

"Sorry, I'm just looking around this whole map. It's pretty alarming," she said.

The interactive map is known as the Zap App.

Simply type in your address in the small rectangular box in the upper left hand corner of the map.

Then hit the minus sign to zoom out to a wider view until you see shaded areas. If the dot indicating the location of your home is in the darkened area, you live in a liquefaction zone.

Take a look at more stories and videos by Michael Finney and 7 On Your Side.

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