Posted on 7/4/2003, 5:19:09 AM by chance33_98
New Maps Show Earthquake Peril for East Bay Cities
New maps released by the California Geological Survey show just how damaging a major earthquake could be to East Bay communities.
They maps show that many low-lying areas near San Francisco Bay would likely liquefy during a major quake, causing buildings to collapse and shattering gas and water mains. Among the areas that would be affected are parts of Fremont, Newark, Hayward, San Leandro and Oakland.
Liquefaction caused extensive damage in the Marina district of San Francisco during the 1989 Loma Prieta earthquake. A number of homes and apartments collapsed, and broken gas mains caused extensive fires.
Liquefaction occurs when water-saturated sandy soil is shaken and, much like quicksand, temporarily cannot support buildings or other heavy structures.
The CGS map also showed problems for those who live on hillsides in the East Bay. The maps single out hilly areas of Castro Valley and Hayward as particularly prone to landslides in the event of a strong earthquake.
The Loma Prieta quake caused a number of landslides near its epicenter in the Santa Cruz Mountains, blocking two lanes of Highway 17 and seriously damaging a number of homes.
Many Bay Area residents are concerned that further efforts to map earthquake-prone communities in the Bay Area may be suspended. Assembly Republican leader Dave Cox of Sacramento has proposed putting the mapping program on hold for three years to save $4 million.
Unless the program is suspended, officials of the CGS are scheduled to map the Peninsula and parts of the South Bay during the next few years.
The maps can be viewed online by clicking on the link below.
Seismic Hazard Maps of the East Bay
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