County’s Mobile Home Damage in Quake Is Called Predictable : Safety: Hundreds bounced off jacks because they were on unstable foundations and in areas known for ground failure.

Mobile homes in Ventura County received widespread damage in the Jan. 17 earthquake--destruction that some say was predictable because the homes were mounted on unstable foundations and located in areas where potential for ground failure was known.

But neither the state nor local governments have laws requiring stronger foundations or disclosure to property buyers of possible ground problems.

Mobile homes, those low-cost alternative homes popular with seniors on fixed incomes, bounced off their jacks by the hundreds in Ventura County, crashing to the ground and shattering the possessions and nerves of their mostly elderly occupants.

In Simi Valley alone, 622 of the city’s 849 mobile homes were severely damaged, many left with their triangular jacks poking through the floor like spikes, city officials said.

At the Crest Mobile Home Village, 40 of the park’s 41 coaches were shaken to the ground. Now, with partial reimbursement from insurance and some help from the federal government, many of the trailers are going back up on jacks, un-reinforced against the next big earthquake, Manager Curtis Atwell said.

“We are a very senior park,” he said. “Our average age here is between 76 to 80 and they just don’t have the money to pay for earthquake bracing.”

Atwell is attaching braces to his own mobile home at a cost of about $2,000, he said. Others have received estimates of up to $2,500.

Foundation problems were compounded during the quake at parks in areas prone to liquefaction, authorities said.

Liquefaction occurs when a high ground-water table and fine-grain soil combine and shake underground like “a bowlful of sand,” as one geologist described the phenomenon. That below-the-surface shaking often causes cracks and other ground failures that send mobile homes reeling and crashing, geologists and engineers said.

In Simi Valley, the liquefaction zone follows the path of the Arroyo Simi, a usually dry river that curves through the south end of the city, the city’s General Plan map shows.

“Mobile homes are the weakest type of building because they have very poor foundations,” said Jean-Pierre Bardet,, professor of civil engineering at USC and a participant in a study on the effects of the earthquake.

“And they are very often located in areas where the soil is not very good. So you are putting poor construction on poor ground and the result is what we see in this quake.”

Like flood zones, liquefaction zones are mapped in city and county general plans.

When a house is subject to flooding during heavy rains, that fact must be disclosed to a potential home buyer. But that’s not the case when a residence is in a liquefaction zone, said Jim Fisher, an engineering geologist for Ventura County Public Works.

Fisher said he plans to introduce an ordinance to the Board of Supervisors to require such disclosure in unincorporated county areas, and he urged city engineers to do the same.

“Cities should require people to file a notice of geological hazard that would go along with the title report,” he said.

The Simi Valley hazard map shows that all five major parks in the city are within the liquefaction zone. Four of the five have a high potential for liquefaction, according to the map.

Only the Trade Winds Mobile Home Park is in an area of moderate potential for liquefaction. At the park, which abuts the Arroyo Simi to the south, 40 out of the 100 mobile homes fell off their supports.

“It was the back part of our park that went down,” said Manager Barbara Hancock. The back part is closest to the zone with the highest liquefaction potential.

At the Friendly Village Park of Simi, 189 of 221 mobile homes fell off their foundations, and the rest were damaged to a lesser extent, Manager June Gray said.

“We’ve got more than 100 put back on their jacks,” she said. “Some are putting on bracing and some aren’t. We should have been told ahead of time we were in a zone like that.”

At Susana Woods Prestige Mobile Home Park, 125 of the 139 coaches came off their jacks, Manager Alice Martens said.

“And the insurance will only pay to put them back the way they were, not for the bracing,” Martens said.

At Simi Country Estates on Rory Lane, 161 of 274 mobile homes were severely damaged, but all of the mobile homes with bracing remained standing, Manager Cathy Pennington said.

There are no local ordinances that regulate foundation requirements for mobile homes because that power rests with the state. And state inspectors are now allowing the repairable mobile homes to be put back up on jacks, with nothing but gravity to hold them steady.

Paul Kranhold, assistant director of the California Department of Housing and Community Development, said the very fact that many of the mobile home residents are on fixed incomes is the primary reason the state does not impose requirements for earthquake bracing.

“A lot of people choose mobile homes because it’s one of the few types of housing that is still affordable in California,” he said. “You take away the affordability factor once you start adding requirements.”

Kranhold said there has been discussion about creating legislation to require the bracing. “But even if there is legislation,” he said, “it is highly unlikely that it would be retroactive” to include existing homes.

Before the next earthquake hits, county geologist Fisher said, the state should require mobile homes to have reinforcements to keep them on their mounts.

“It’s not a matter of if we have another earthquake, it’s when,” he said. “That we know.”

Simi Valley Liquefaction Zones

Moble homes located in liquefaction zones that suffered severe damage in the earthquake. 1. Friendly Village of Simi 2. Trade Winds Mobile Home Park 3. Crest Mobile Home Village 4. Simi Country Estates 5. Susana Woods Prestige Mobile Home Park