The Northwest hasn’t had a killer earthquake since 1965 – and it’s been three centuries since anything massive shook this region. That’s how New Zealanders felt, until two years ago, when a quake knocked their third largest city to its knees.
Lessons from Christchurch, NZ, and other Pacific Rim cities, are resonating at a meeting of the Earthquake Engineering Research Institute, in Seattle this week.
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Christchurch, a city comparable to Spokane, suffered a series of quakes in 2010 and 2011, on a newly discovered fault. It's a shallow fault, much like the Seattle and Tacoma faults, which were only discovered in the 1990s.
"A lot of Christchurch residents will tell you they didn’t really expect it to happen," says David Johnston, who runs a disaster research center at Massey University in New Zealand and frequently consults for the state of Washington. 'There would be talk that earthquakes could occur, but they saw themselves as much lower risk than other areas of New Zealand."
People in Washington state might feel the same in comparison to high-risk California.
Some of the most eye-popping damage in Christchurch included:
- a concrete office building that truly crumbled and killed 115 people inside;
- the central downtown business area surrounded by chain-link fence because so many brick buildings were in various states of collapse;
- entire residential neighborhoods abandoned, because the soil beneath them had liquefied.
Today, most of Christchurch’s historic brick buildings are gone.
Bricks have been a problem in smaller earthquakes that hit Olympia, Seattle and Tacoma, says Craig Weaver of the US Geological Survey in Seattle.
"We have seen all we need to know. We just need to take lessons from Christchurch and apply them in Seattle," says Weaver.
Seattle leaders have attempted to pass a law requiring building owners to shore up nearly a thousand brick structures, but they keep running up against the cost. Retrofits are expensive, and a law might push owners to simply demolish their brick buildings, instead. A task force has been looking for a compromise, to preserve neighborhoods and historic structures but make them safer.
Washington gets credit for taking steps to reinforce bridges and other infrastructure.
Leaders here are conscious that Washington seems overdue for a big one. The regions surrounding the Pacific Ocean, ringed by volcano and earthquake zones, have been labeled the "Pacific Ring of Fire."
“Most areas on that ring of fire have had a very damaging earthquake in the last 50 years or so," including New Zealand, Chile and Japan, says structural engineer Mark Pierepiekarz of Bellevue. "The Pacific Northwest, British Columbia area is the last gap, where there hasn’t been major earthquake in 300 years.”
