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NR 2002-30
June 30, 2002

Contact: Carol Dahmen
Mark Oldfield
Don Drysdale
Ed Wilson
(916) 323-1886

TWO OFFICIAL SEISMIC HAZARD ZONE MAPS RELEASED
Developers, Planners, Real Estate Sellers Must Be Aware
Of Newly Defined Zones in the Santa Paula and San Clemente Areas
 

SACRAMENTO – Two Seismic Hazard Zone maps – one for a portion of Orange County and another for part of Ventura County – become official Friday. The maps impact local planners, developers, property sellers and real estate agents.

If property is located in a “zone of required investigation,” where liquefaction or landslides could occur during a large earthquake, the local building department must require geologic studies before projects are issued permits. Also, property sellers and real estate agents must inform potential buyers if property they're selling is in a Seismic Hazard Zone, as is the case when property is in a designated flood or wildfire zone.

The Seismic Hazard Zone map for the 62-square-mile Santa Paula quadrangle, which includes portions of the cities of Santa Paula and Camarillo, are official after six months of public review and comment. The map – part of an ongoing California Department of Conservation project -- is on file with local government offices, including the planning department, building department and county recorder's office.

The "zone of required investigation" for liquefaction occurs south of Santa Paula as a broad area, spreading from the foot of the mountains along the Santa Clara River north to just beyond the Santa Paula Freeway (Highway 126).

Landslide hazard zones occur northwest of Santa Paula in the steep hillsides above Foothill Road, easterly to Ojai Road (Highway 150). Heavy concentrations of landslide hazards occur in the mountainous areas south of the Santa Clara River to La Loma Ave. and Berylwood Road. Hillsides south of Los Angeles Avenue (Highway 18) are also susceptible to landslide hazards.

For more information, contact your local building department.

The San Clemente quadrangle map covers about 28 square miles in Orange County, including the city of San Clemente and a small part of San Juan Capistrano.

Liquefaction zones occur along the coastal beach areas from La Paloma Street south to the county line and in the low-lying areas extending across Interstate 5 from Bicentennial Park northwest to San Clemente High School. Other liquefaction zones include the bed of Sequnda Deshecha Creek along Avenida Pico just north of Highway 5, Cañada Creek in San Clemente, Christianitos Canyon, and Cabino Canyon.

Landslide hazard zones are shown in southern coastal San Clemente in the heavily developed cliff areas between the freeway and the beach west of Highway 5, most of the mountainous areas from Highway 5 north to the San Juan Capistrano city limits, and from Marblehead Park east to the peaks past the Shorecliffs golf course. Other scattered landslide hazard zones occur from Christianos Canyon east to the San Diego County line.

Shaking causes most of the damage during earthquakes, and in many cases, it is cost effective to retrofit houses and buildings to minimize damage caused by severe shaking. Local public libraries have a number of publications by the Governor’s Office of Emergency Services, American Red Cross and the Federal Emergency Management Agency that can be used as guides to making homes more earthquake-ready.

Seismic Hazard Zone maps produced by DOC's California Geological Survey show areas at risk from the secondary earthquake hazards of landslides and liquefaction, which also can be dangerous. It is generally not as cost effective to retrofit an existing building for the impacts of liquefaction or landslides as it is to build in safety features at the design stage. Therefore, design changes are required before new developments are approved and constructed in order to be effective. Changes made during the planning phase can lessen the impact and better protect life and property during future earthquakes. The new maps are important tools that land developers will use to ensure project feasibility.

Fifty-seven maps affecting Southern California are now official. Seven new preliminary maps are in the review stage. The new maps include the Santiago Peak quadrangle in Orange County and the Pitas Point, Saticoy, Ojai, Fillmore, Piru, and Val Verde quadrangles in Ventura County. Landslide and liquefaction mapping is continuing in the Lancaster-Palmdale area and is scheduled for release later this year.

Color copies of official maps can be purchased by calling DOC's California Geological Survey at (213) 239-0881 or (916) 445-5716. The maps also can be found on the Web here.

In addition to studying and mapping earthquakes and other geologic phenomena, the Department of Conservation maps and classifies areas containing mineral deposits; ensures reclamation of land used for mining; regulates oil, gas and geothermal wells; administers agricultural and open-space land conservation programs; and promotes beverage container recycling.

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