Updated quake map tells you if you live in a liquefaction zone

It also highlights areas at risk of landslides

Updated 2:00 pm PDT, Monday, April 8, 2019

A new earthquake mapping app shows liquefaction- or landfill-prone zones in California. The app allows users to zoom down to block level to see if their home lies in any of the at-risk areas. Photo: California Dept. Of Conservation

Beside number of bedrooms and quality of school districts, prospective Bay Area home buyers might want to consider their target home's chances of survival in the event of a major earthquake.

After all, the latest research shows that California is long overdue for a massive, ground-rupturing temblor on a major fault. We haven't had one in 100 years.

An online map application from the California Geological Survey (CGS) can help. The California Earthquake Hazards Zone Application (EQ Zapp) drills down to the block level to show if your house (or one that you're looking to buy) sits on sturdy ground or if it's at risk of liquefaction or landslides during a quake of 5.5 magnitude earthquake or larger.

The data that the app draws on for San Francisco is nearly 20 years old. The liquefaction zones shown in dark green are well-known — landfill areas including the Marina, Fisherman's Wharf, Dogpatch and South of Market. Landslide-prone areas are marked in light blue.

The CGS last week released five new Seismic Hazard Zones maps affecting communities in Contra Costa and San Mateo counties. They are:

Antioch North quadrangle
Antioch South quadrangle
Honker Bay quadrangle
Montara Mountain quadrangle
Woodside quadrangle.

The Contra Costa communities covered include all or parts of Antioch, Concord, Brentwood, Oakley, Pittsburg and Bay Point. In San Mateo, communities impacted include all or parts of Woodside, San Carlos, Belmont, Burlingame, Half Moon Bay, Hillsborough, Millbrae, Redwood City, San Bruno, San Carlos, Portola Valley and Pacifica.

Some Bay Area locations – for example, northern Pacifica and Daly City — have not been evaluated for liquefaction or landslide.

Photo: Otto Greule Jr, Getty Images

Damage to the Marina District, San Francisco, following the 1989 Loma Prieta earthquake.

Living in an area with high risk of liquefaction does not necessarily mean your house will be damaged should a major quake strike. Newer buildings and retro-fitted structures are better equipped to weather temblors, especially those in modern, engineered artificial fill zones.

You can read more about about the Bay Area's liquefaction zones here.

Source: https://www.sfgate.com/realestate/article/sf-bay-area-california-earthquake-map-zones-13750983.php