Science reporter gives talk on earthquake history, what’s next
EVERETT - Spread under Snohomish County and the Puget Sound region lie earthquake fault lines scientists are diligently monitoring.
Offshore, a vast fault line along the ocean floor runs from northern California to British Columbia called the Cascadia Subduction Zone, where the sea floor plate rubs the plate under North America.
The good thing is that the Pacific Northwest is aware of its earthquake risks, said Sandi Doughton, the Seattle Times’ science reporter.
Doughton was at the Everett Library Wednesday, Sept. 25 to discuss local earthquake history and what may happen in the future.
Compared to Christchurch, New Zealand, which was shaken by a 6.3 magnitude quake in 2011, the Pacific Northwest is way ahead of the curve. New Zealand had no idea fault lines ran underneath it, Doughton said.
Bill Steele’s colleagues at the University of Washington Pacific Northwest Seismic Network are working to create an early warning system to give people a few minutes warning of an earthquake. The system could come online by 2015, Steele said.
Realistically, when, where and if the next quake will happen is unknown. Scientists predict the Pacific Northwest has a 15 percent chance of a major earthquake in the next 50 years, Steele said.
Snohomish County residents would be most affected if the South Whidbey Island Fault shook. Everett lies right over the fault line and its waterfront would liquefy from the shaking because it’s built on fill dirt, Doughton said. “It would turn to goo,” she said.
The last time the South Whidbey Island Fault had a major quake was 2,500 to 2,700 years ago, Doughton said.
Another “deep earthquake,” like the 2001 Nisqually quake where people as far south as Seattle felt, is more likely to come sooner, Steele said.
“I think we need to be prepared for (a big earthquake) in our lifetime,” he said.
Earthquakes, though, are survivable, Steele and others emphasize. The economic impact and potential for thousands of people to be displaced from crumbled homes is the greater issue.
The large 6.8 magnitude Northridge earthquake in Los Angeles almost two decades ago destroyed $20 billion in bridges and buildings and killed 57 people. The midday Christchurch earthquake killed almost 200.
Predictions on a worst-case scenario for the South Whidbey Island Fault suggest a 7.4 magnitude earthquake would kill a few hundred, but displace 14,000 people who will need shelter.
Doughton said any big earthquake would destroy bridges and rupture water and sewer lines.
At least one simple step to help save your house is reinforcing the home to the foundation, experts said.
The major killer is when buildings collapse. Earthquake watchers have called for stronger seismic codes and retrofitting requirements.
Seattle’s been working on a seismic retrofit code for the past five years and an ordinance laden with incentives to retrofit buildings may be ready for the City Council next year, Seattle Department of Planning and Development spokesman Bryan Stevens said.
Doughton said there are 11,000 brick buildings between Portland and Vancouver vulnerable to fall.
“Many were built before we knew we were subject to giant quakes,” Doughton said. Part of what makes these buildings vulnerable is that the floors are not connected to the walls.
Scientists started discovering most of these old fault lines in the past 20 years, Steele said.
It’s been centuries, though, since the Pacific Northwest’s last major earthquake when the subduction zone ripped apart with an estimated 9.0 magnitude earthquake. The research behind the predicting of the next such quake is the basis of Doughton’s book “Full Rip 9.0.”
The subduction zone has a major earthquake every 500 years, meaning it’s been 313 years since the last major quake.
That earthquake hit Jan. 26, 1700, and computer models suggest the resulting tsunami waves reached Japan.
How to prepare for and deal with an earthquake
There are many ways to stay safe during an earthquake, but preventative measures can ensure your safety. Mary Schoenfeldt of Everett’s emergency management department offers these tips:
• Always keep an emergency kit in your car, regardless of quake risks. In the kit, have a flashlight, batteries, simple tools, first aid items, water, nonperishable food like snack bars and other items.
• Keep seven-day stocks of extra water, pills, baby food, pet food and nonperishable food that don’t require cooking. Locate these in accessible parts of the house.
• Put on hard-soled shoes, and preferably have some under your bed. Broken glass is a real hazard after an earthquake.
• Try to own a water filtering system, even if it’s a $30 water filtering bottle intended for camping. An earthquake can rip apart water and sewer lines, possibly for weeks.
During an earthquake:
• Duck and cover under a solid table or desk if you can.
• Stay inside. It’s more likely things could fall on you outside.
• If outside, get away from buildings as best you can. It will be difficult, though, to move or walk during an earthquake.
• If caught while driving, get off any bridges and stay away from underpasses. Pull off the road and pull the emergency brake until the earth settles.
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