SEATTLE-"We got problems here."
So explained Craig Weaver, a seismologist for the U.S. Geological Survey and chief of its Pacific Northwest earthquake studies project. "There will be earthquakes. You can take that to the bank."
This is not what you want to hear if you have taken much of your life savings out of the bank–as I have–and bought an old house in Seattle.
Alone among U.S. cities, Seattle has the dubious distinction of having had since 1949 three damaging earthquakes that toppled brick buildings and caused some low-lying ground to turn into a sandy liquid. But there is even more worrisome news. Seismologists have learned that Seattle, like Los Angeles and San Francisco, might have a Big One in its not-too-distant future.
A rupture along the Seattle Fault, which runs under the south end of the city and was unknown until 1992, would kill 1,600 people, injure 24,000 others, destroy 9,700 buildings and damage about 180,000 other structures, according to a scenario put together by earthquake experts and published last year with funding from the state of Washington.
Big Ones occur here about every thousand years, much less frequently than in California. The last one occurred in what is now Seattle 1,100 years ago. By the geologic clock, this city is due for a catastrophic shake that the builder of my old house had no idea was even a remote possibility. About a quarter of a million houses in and around Seattle are in the same fix.
What’s an anxious homeowner to do?
The answer in Seattle–as across the earthquake-prone West Coast–is surprisingly simple to explain: Bolt that old house to its concrete foundation.
Structural engineers say that even an old wooden house is strong enough and flexible enough to survive a major earthquake without serious structural damage–if it is not shaken off its foundation. In this part of the country, most houses built after 1975 are bolted down.
My house was built in 1904.
So I called 877-2-BOLT-IT, and on a recent Saturday afternoon attended a home retrofit class sponsored by the city of Seattle.
Tom Hall, the volunteer instructor, is a 30-something seismic retrofitter with a shaved head and a thin, agile body. He had hauled into the auditorium of a local library a simulated concrete basement foundation wall and an dizzying array of power tools, bolts and anchor plates.
We students were middle-aged men and women. We were not thin and agile. We had come with notebooks, pens and hope that we could save thousands of dollars by bolting in our basements in our spare time.
That hope, at least in my case, melted away as Hall explained what a retrofitter should wear and know.
We should wear goggles, gloves, overalls, kneepads and a respirator. We should rent or buy a compressor-driven nail gun, a roto hammer drill and a torque wrench–plus a great many other tools I had never used. We should know that many people spend 100 hours or more in their basement before the bolting is done right.
A poorly done or half-done retrofit can be worse than no retrofit at all, Hall told us, noting that one do-it-yourselfer in Seattle had gotten it very wrong: His partially retrofitted house leaned over in a rainstorm and crushed him to death.
Even if you do it all yourself, it costs about $1,500 for permits, tools and hardware. Expect to spend at least 40 hours in the basement –if you are handy with a roto hammer. If you are not and if you hire a professional, expect to spend between $5,000 and $20,000–on a project that no will see and that will come into play only if the Big One hits. The U.S. Geological Survey sets the local odds at 5 percent over the next 50 years.
About 125,000 houses need bolting in Seattle, but just 4,300 people (plus 400 professional contractors) have attended a free retrofit class in the past eight years, and only about 900 fast-tract permits have been issued by the city to do the work.
"People are not yet onboard," Hall conceded.
Ines Pearce, who for nearly eight years managed Seattle’s program to retrofit houses, has inventoried the reasons they are not onboard in large numbers.
Most Seattleites safely rode out earthquakes in 2001, 1965 and 1949 without serious damage to their houses, she said, adding that many did not realize those quakes were relatively benign tremors that gave the city a fairly smooth ride.
A rupture on the Seattle Fault would be terribly different–similar to the catastrophic 1994 earthquake in Northridge, Calif. The strongest urban earthquake ever recorded in North America, it brought down freeways, office buildings and parking lots. It shook thousands of houses off their foundations while killing 61 people and causing more than $40 billion in damage.
"While people’s perception of risk has gone up in Seattle, they don’t know how to differentiate between the level of threat from different kinds of quakes," Pearce said.
Pearce, who recently moved to Los Angeles, said Seattle politicians know it would be unpopular to require that homeowners bolt down their houses. "They want to be re-elected," she said.
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Title: Homes safe from quakes | Author: Blaine Harden | Section: News | Published Date: 2006-11-29 | Internal ID: 5313