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SEATTLE (AP) -- The tidal waves that killed thousands across Asia over the weekend are similar to one that struck the West Coast more than 300 years ago, scientists say.
On Jan. 26, 1700, an earthquake of approximately magnitude 9.0 buckled the ocean floor from Vancouver Island to Northern California, setting off a tsunami that swamped the coast and washed away houses in Japan.
Sunday's quake was about the same magnitude, occurred on a north-south fault and, like the 1700 quake, had a "rupture length" -- the length of fault that slipped in the quake -- of about 600 miles.
"The parallels are incredible," said Brian Atwater, a U.S. Geological Survey geologist based at the University of Washington.
Atwater is credited with discovering the quake caused the Washington coast to drop suddenly by 5 feet.
The National Tsunami Hazard Mitigation Program, a partnership of state and federal agencies, has developed maps and evacuation plans for at-risk coastal areas in the Pacific states.
In Washington state, Whidbey Island, Port Angeles, Port Townsend and Bellingham are at particular risk.
Tucked into Puget Sound, Seattle is not at significant risk from an open-ocean tsunami, Atwater said. But a strong quake along the Seattle Fault could touch off damaging waves on Puget Sound and even Lake Washington.
Vasily Titov, a research oceanographer at the National Oceanic and Atmospheric Administration's Pacific Marine Environmental Laboratory in Seattle, develops models of tsunami propagation.
He said international monitoring has focused on the Pacific Ocean, because that's where 90 percent of tsunamis occur.
"In the Indian Ocean, there is tide-gauge information, but there isn't a 24-7 warning system," Titov said.
The West Coast and Alaska Tsunami Warning Center in Palmer, Alaska, combines seismic and deep-sea pressure data with tsunami-prediction models to produce constant updates on potential threats.
The international effort was started after a 1946 earthquake in the Aleutian Islands.
That quake touched off a tsunami that raced across the North Pacific, hitting Hawaii with 55-foot waves five hours later and killing 173 people.
On Sunday, scientists in Western Washington received a tsunami alert, but many of the Asian nations that were struck did not.
Tim Walsh, program manager for geologic hazards with the Washington Department of Natural Resources, said he was notified about the Sumatra quake before the waves hit the shores.
The monitoring system for the Pacific correctly reported that the quake wouldn't be a threat to the Washington coastline.
"We knew about that here but didn't realize how bad it would be over there," Walsh said.
------
On the Net:
West Coast and Alaska Tsunami Warning Center: http://wcatwc.gov
On Jan. 26, 1700, an earthquake of approximately magnitude 9.0 buckled the ocean floor from Vancouver Island to Northern California, setting off a tsunami that swamped the coast and washed away houses in Japan.
Sunday's quake was about the same magnitude, occurred on a north-south fault and, like the 1700 quake, had a "rupture length" -- the length of fault that slipped in the quake -- of about 600 miles.
"The parallels are incredible," said Brian Atwater, a U.S. Geological Survey geologist based at the University of Washington.
Atwater is credited with discovering the quake caused the Washington coast to drop suddenly by 5 feet.
The National Tsunami Hazard Mitigation Program, a partnership of state and federal agencies, has developed maps and evacuation plans for at-risk coastal areas in the Pacific states.
In Washington state, Whidbey Island, Port Angeles, Port Townsend and Bellingham are at particular risk.
Tucked into Puget Sound, Seattle is not at significant risk from an open-ocean tsunami, Atwater said. But a strong quake along the Seattle Fault could touch off damaging waves on Puget Sound and even Lake Washington.
Vasily Titov, a research oceanographer at the National Oceanic and Atmospheric Administration's Pacific Marine Environmental Laboratory in Seattle, develops models of tsunami propagation.
He said international monitoring has focused on the Pacific Ocean, because that's where 90 percent of tsunamis occur.
"In the Indian Ocean, there is tide-gauge information, but there isn't a 24-7 warning system," Titov said.
The West Coast and Alaska Tsunami Warning Center in Palmer, Alaska, combines seismic and deep-sea pressure data with tsunami-prediction models to produce constant updates on potential threats.
The international effort was started after a 1946 earthquake in the Aleutian Islands.
That quake touched off a tsunami that raced across the North Pacific, hitting Hawaii with 55-foot waves five hours later and killing 173 people.
On Sunday, scientists in Western Washington received a tsunami alert, but many of the Asian nations that were struck did not.
Tim Walsh, program manager for geologic hazards with the Washington Department of Natural Resources, said he was notified about the Sumatra quake before the waves hit the shores.
The monitoring system for the Pacific correctly reported that the quake wouldn't be a threat to the Washington coastline.
"We knew about that here but didn't realize how bad it would be over there," Walsh said.
------
On the Net:
West Coast and Alaska Tsunami Warning Center: http://wcatwc.gov
