Japan tsunami a wake-up call for US west coast

Japan’s massive earthquake and tsunami is alerting the US west coast that the same kind of thing could happen here. In fact, say experts who study the earth’s shifting crust, the “big one” may be past due.

Both Japan and the Pacific Northwest lie along subduction zones – areas where tectonic plates push against each other. When the growing pressure finally gives way, earthquakes and related tsunamis result.

The Cascadia subduction zone (“Cascadia fault”) is where the Juan de Fuca and North America plates meet – sometimes in violent confrontation. It’s part of the “ring of fire” – volcanoes and earthquakes surrounding the Pacific Ocean. The Cascade Mountain Range – which includes Mount St. Helens – is volcanically active.

IN PICTURES: Japan's 8.9 earthquake

The last time a “big one” of the type Japan saw Friday occurred along the northwest coast was on Jan 26, 1700. Judging by the number of times that’s happened over the past 10,000 years, some scientists think another one is due this century.

“It has happened in the past. It will happen in the future,” Portland State University geology professor Scott Burns told KPTV in Portland, Oregon.

“It would be devastating,” said professor Burns. “There would be a lot of damage.”

The Pacific Northwest is dotted with tsunami warning devices that could give people the critical few minutes needed to reach higher ground. But in many areas, building codes and construction have not advanced to the extent they have in Japan.

“We’re getting better about people taking this stuff seriously,” Robert Butler, a geophysicist at the University of Portland, told The Columbian newspaper in Vancouver, Wash. “I credit the 2004 tsunami in the Indian Ocean for a step-up in awareness.”

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