Experts Say Area Ill-Prepared for Quake : Emergencies: Scientists also warn that local faults are capable of shaking Ventura County as hard as the Northridge temblor shook the San Fernando Valley--or harder.
Geologists warn that Ventura County’s governments are ill-prepared and dangerously indifferent to a new report that puts the county smack in the middle of severe earthquake territory.
But government officials say the Southern California Earthquake Center’s report offers nothing new. The county and its cities, they say, are as ready as they can be for a major earthquake.
It is an old debate, with a new urgency.
Scientists have often made grave, if imprecise, forecasts that a severe earthquake lurks in Ventura County’s future.
Government planners have often acknowledged the danger, saying there is little more they can do with the money and laws at their disposal.
And the people of Ventura County, officials and geologists add, often choose to ignore the threat.
But the report released Jan. 20 carries more specific warnings than Ventura County has ever heard before.
The center’s scientists predict that Southern California is entering a new age of earthquake activity after 200 years of relative quiet.
They mapped fault lines across Southern California, calculating that Ventura County occupies high-risk earthquake country.
They forecast a 60% chance in the next 30 years that Ventura County’s ground will shake with at least 20% of the force of gravity--enough to knock items off shelves and start causing structural damage. Ground shaking in last January’s Northridge earthquake topped 70% of the force of gravity in parts of eastern Simi Valley.
And the scientists said Ventura County’s fastest-moving faults are capable of shaking the region as hard as the Northridge quake shook the San Fernando Valley--or harder.
Meanwhile, the county General Plan’s seismic data is decades out of date, said Jim Fisher, the former staff geologist for Ventura County.
Fisher said he quit three weeks ago in part because the Board of Supervisors ignored his pleas to seek money from the Federal Emergency Management Agency to upgrade the General Plan’s earthquake chapter.
“Their plans are based on data that’s 50 years old in some cases,” said Fisher, who works for a Camarillo engineering firm. “Their map that shows the location of faults, for example, it doesn’t reflect blind thrust faults or any newer information on seismicity.”
The maps are indeed out of date, said Art Goulet, the county’s public works director.
But supervisors did approve the FEMA application, Goulet said, and they merely held off deciding whether to pay the county’s 25% share of the plan update.
With old, inaccurate data, Goulet said, county planners erred on the side of caution, placing large developments possibly farther than necessary from active faults.
“Consider the type of development that exists in Ventura County,” he added. “For the most part, Ventura County is low-rise construction, and not dense construction. Arguably, even in the Northridge earthquake, low-rise, non-dense construction did not suffer dramatically.”
Ventura County has always carried the state’s highest seismic danger rating, said Thousand Oaks building official Barry Branagan, and existing building codes are tough enough to protect lives.
Also, he said, Thousand Oaks inspectors require soil tests for new construction and pay close attention to wall and frame connections in all new buildings.
“It’s my personal opinion that we can’t just unilaterally start changing the law because I got a report from a bunch of people that say it’s so,” Branagan said last week. “The only reason I can change it is on geological grounds, which is earthquakes. I’ve got no geological evidence to show (Thousand Oaks) is any different from the San Fernando Valley, the San Andreas fault or anywhere else in California.”
One geologist called that attitude “irresponsible.”
With three fast-moving faults converging in Ventura County and no history of a severe earthquake since 1812, the region is due for a bad one, said geology professor Bob Yeats, an expert on the county’s fault-line system.
The mountains north of Ventura are slowly moving south, and the force building up in the San Cayetano, Oak Ridge or Santa Susana faults could release itself in a single, severe earthquake or several moderate-to-severe earthquakes over 25 years or so, Yeats said.
What’s more, he said, scientists believe the Oak Ridge fault is an extension of the fault that caused the Northridge quake. And because the Oak Ridge fault’s slip rate is three times faster than its recently active neighbor, it is also three times as likely to cause an earthquake, Yeats said.
“We can’t give the confident answer that insurance adjusters would like. Our technology’s not that good,” said Yeats, who worked on the center’s report. “But we can say that people that are living within range of the ground shaking of the Oak Ridge and San Cayetano faults should be prepared for an earthquake of the Northridge type.”
The county’s emergency agencies say they are as ready as possible for the next earthquake.
Every disaster, they say, including this month’s flooding, sharpens their skills.
“We are very vulnerable in Ventura County to experience a major quake, so our plans still are reflecting that,” said Wendy Haddock, assistant director of the sheriff’s emergency services office. That office coordinates rescue efforts in disasters among the county fire and sheriff’s departments, and police and emergency agencies around the county.
“The plan’s only as good as the response organization behind it,” she added. “I’m not saying, ‘Yeah, we can handle anything that’s thrown at us.’ But we’re getting very good at what we should be. . . . It’s a learning process and, theoretically, I don’t think we could speed it up. We’ve got training going on constantly.”
Some emergency officials take almost a fatalistic attitude toward the inevitability of earthquakes in Ventura County.
“I’m not the first to say this, but part of living in Southern California is that you have the potential for earthquakes,” Ventura Fire Chief Dennis Downs said. “Short of making sure our construction standards are such that we could withstand an earthquake, and being prepared to handle the effects after the fact, there’s not much we can do.”
But changing construction standards can be complicated and unpopular:
Fillmore and Santa Paula are near the San Cayetano and Oak Ridge faults.
And Ventura lies within striking distance of the Santa Cruz fault beneath the Channel Islands, which has the potential to unleash an earthquake as strong as magnitude 7.4, the report states.
By all accounts, brick buildings in all three cities hold the greatest threat of collapsing and killing people in a severe quake.
But fierce opposition by property owners shot down laws that would have required such buildings to be hardened against earthquakes--in Santa Paula in 1985, and Ventura in 1991.
Instead, officials in those cities settled for ordering owners of brick buildings to anchor brick parapets. They also asked for voluntary full-scale structural reinforcements, but few owners have done that, officials said.
“We were disappointed that we didn’t get a stronger un-reinforced masonry ordinance,” Ventura building official Bob Prodoehl said. In a serious earthquake, he said, “We know that the downtown will be considerably damaged.”
Fillmore saw the Northridge earthquake all but shatter its brick business district. But the city can only require retrofitting for heavily damaged brick buildings, City Manager Roy Payne said.
“Once the dust settles on the earthquake recovery, we will go back and take a look at (the other) buildings and try to come up with some sort of program to get those buildings retrofitted,” Payne said.
City and county officials said they must wait for upcoming changes to the California Uniform Building Code for a chance to force improved safety in Ventura County’s few steel-frame buildings.
After the Northridge earthquake, the Board of Supervisors amended the county building code to require stronger construction for new wood-frame houses. And Camarillo is expected to follow suit. But other cities are waiting for the statewide code changes, saying the existing code is strict enough.
They recommend that homeowners ensure that their older wood-frame houses are properly anchored to their foundations, and that they do interior earthquake-proofing such as strapping down water heaters.
“Wood-frame, single-family homes perform very well in an earthquake,” said Michael Kuhn, senior planner in Simi Valley. “But short of tearing the stucco off and putting in plywood on the outside of the structure, there really isn’t much you can do.”
Such work is costly, he said.
The 1994 state building code requires all newly built structures to protect human life in an earthquake, but it also expects them to incur severe damage, said Thomas F. Blake, a Ventura geologist and engineer who worked on the Jan. 20 report.
“If society decides that they want better performance from their structures, then society’s going to have to be willing to pay for it,” he said. “They have to expect there will be damage, there will be cracking, there will be more costs associated with repairs.” Officials and geologists agreed that residents should do more to be prepared for a severe earthquake.
“As taxpayers and citizens, we’re spending a lot of money after the fact,” said Tom Waller, Oxnard’s fire engineer and the city’s disaster service coordinator. “If we spent one-tenth of the money beforehand on a little harder building and construction design, and a little better methods of making people’s homes and work environments safe . . . then we’ll have far fewer injuries and the dollar loss will be far less.”
Blake, the geologist, added, “If you ask people (if) they know they’re in danger . . . they say, ‘Oh yes, we’re aware of that.’ But the first time they experience a financial loss, they say, ‘No, we didn’t know, it’s someone else’s fault.’ ”
Ventura County Faults
The threat of severe earthquakes is locked up in active faults directly under Ventura County. The Oak Ridge and San Cayetano faults are among the fastest-moving of these, with rocks on either side grinding past each other at a rate of nearly one-fifth inch per year. The Santa Susana fault near Simi Valley moves even faster, at nearly one-quarter inch per year. The Santa Cruz fault has the potential to cause earthquakes measured at magnitude 7.4.
Source: 1994 Working Group on the Probabilities of Future Large Earthquakes in Southern California.