Quake Dangers in Simi, Moorpark Mapped

A huge swath of Simi Valley and parts of Moorpark could experience landslides and liquefying soil in an earthquake, and development there should proceed only after precautions are enacted to address such hazards, according to new maps and building guidelines released Tuesday by state geologists.

But local planners say the maps developed by the state Division of Mines and Geology offer few surprises and that the cities already have in place some of the precautions recommended for building in quake-prone zones.

The maps show areas of possible quake-induced liquefaction stretching from western Simi Valley, snaking along the city’s southern border and creeping into the eastern edge of Moorpark.

State geologists hope to map all of the populated areas of Ventura County by mid-1998, provided they receive funding.

Under the new state rules, developers who want to build in such hazard zones must study the geological conditions of their project sites and design ways to deal with those conditions before winning approval for their projects.

Those precautions could include driving support struts deep into the earth to fortify buildings, draining subsurface water that could liquefy the soil and removing soft earth from construction sites.

In most cases, single-family homes built individually are exempted from the new building guidelines. However, the new guidelines do require people with land in liquefaction zones to disclose that fact to buyers.

Urban planners in Moorpark and Simi Valley say some of the new requirements aren’t new to them. For example, both cities already demand soil studies from developers as part of the process of granting city approval.

“Moorpark has pretty much done those things already,” said Nelson Miller, the city’s community development director.

As for Simi Valley, one state geologist who worked on the new maps said the city is more diligent than some in requiring seismic studies.

“The city of Simi Valley does a good job of this,” said Tim McCrink, a senior engineering geologist with the state agency. “Some of the smaller cities without the resources don’t.”

The maps, in fact, rely heavily on data culled from seismic studies submitted to Simi Valley officials over the years by developers, said senior planner Michael Kuhn.

Kuhn and Miller said the maps will help provide the most up-to-date and precise look yet at areas prone to liquefaction during earthquakes. Liquefaction occurs when heavy shaking hits soil relatively saturated with water, causing the earth to move much like quicksand.

Local Realtors were unsure Tuesday what the new disclosure requirement would mean to local property owners.

Debbie Rodgers Teasley, district manager for Coldwell Banker Town and Country, said the state previously recommended that sellers disclose whether their property has potential liquefaction problems.

Some companies currently offer to search public records for such problems, often for about $40 or $45.

Teasley, who also serves on the Moorpark City Council, said she hoped such disclosures would not hurt people trying to sell their homes.

“I don’t foresee it being a problem,” she said, “if only because it’s not unusual in Southern California to have liquefaction.”

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FYI

For a look at the state’s seismic hazard maps or for more information on the new building guidelines, access the Division of Mines and Geology’s Internet Web site at https://www.consrv.ca.gov/dmg/shezp/ Copies of the maps also will be provided to each city hall.

* SEISMOLOGY

State agency urges controls in mapped earthquake zones. A3