The California Department of Conservation has released a map for local government officials to see what areas in San Jose and Santa Clara County are vulnerable to earthquakes and where to take precautions when planning construction projects, a spokesman said.
The mapped area encompasses about a 30-square-mile swath of the city and the county where ground might slide and cause soil to become loose or "liquefy" during temblors, said Ed Wilson, department spokesman in Sacramento.
San Jose-area government officials can use the map to make decisions on where to restrict building projects to lessen the likelihood of human injury and property damage from earthquakes, Wilson said.
"It gives local planners an idea of areas that might be prone to landslides and liquefaction," Wilson said. "How they choose to use it, they go on from there."
John Parrish, state geologist and head of the California Geological Survey that prepared the map, said the chart is the survey's first seismic hazard map that shows all of the hazardous areas of Santa Clara County in one place.
The map displays areas where quakes are most likely to produce landslides and liquefaction and the location of Alquist-Priolo Earthquake fault zones, where surface ruptures may occur, Parrish said.
The map for Gilroy has not yet been completed, but Morgan Hill has.
The San Jose and Santa Clara County map is the latest in a series of seismic guides being released by the survey to show earthquake-prone regions throughout the state, Wilson said.
The Seismic Hazards Mapping Act, passed into law by California Legislature in 1990, mandates the creation of maps of quake-prone areas in the state, following the 1989 Loma Prieta earthquake that triggered landslides and soil liquification across the Bay Area.
The state has already released more than 100 such maps, according to Chuck Real, supervising geologist for the survey, who added that the maps have had no effect on real estate prices in California.
The chart of hazards in San Jose and in Santa Clara County is known as the Lick Observatory Quadrangle Seismic Hazard Zone map.
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