From: Reuters
Published March 8, 2005 12:00 AM

Pacific NW Undersea Quakes Intrigue Scientists

VANCOUVER, British Columbia — Scientists searched Monday for signs of a volcanic eruption off the Pacific Northwest coast following a swarm of earthquakes that posed little risk of causing a tsunami but could teach them about how the Earth's crust forms.

A research ship was monitoring the ocean floor about 170 miles west of Vancouver Island, looking for fresh lava in an underwater area known for its hot water geysers and unusual microbes that can survive in the super-heated temperatures.

Geologists stressed there was very little risk of a tsunami being triggered by the swarm. More than 3,700 quakes were recorded between Feb. 27 and March 4 along the Juan de Fuca Ridge. The seismic activity has now slowed.

Bill Steele, a seismologist at the Pacific Northwest Seismograph Network at the University of Washington, said the quakes are caused by the separation of the tectonic plates.

"It's quite exciting. ... This (area off Vancouver Island) is where plates are being created. Tsunamis come from where plates are being destroyed," said Steele.


A tsunami on Dec. 26 left about 300,000 people dead or missing in the Indian Ocean region.

None of the earthquakes was strong enough to be felt by coastal communities in Washington state or British Columbia, but they indicated magma was moving in the area, said Geological Survey of Canada seismologist Garry Rogers.

"We don't know if there has been ejection of magma on the sea floor. It has all the characteristics of magma movement, but it could all be below the sea floor," Rogers said.

The scientists hope that observing a lava flow will teach them more about how tectonic plates are created. The ship will look first for heat and chemical evidence of new lava.

"If they find something, they'll zero in on it and I expect put down some cameras to see what they can see," Rogers said.

A ship checked the region after an earthquake swarm in 2001 but failed to find any new lava on the floor.

Rogers said the area being searched is just north of the Endeavour Hot Vents, a special marine protection area established by the Canadian government last year.

About a dozen species of microbes live amid the geysers spewing water heated up to 572 F, and there are bacteria feeding on hydrogen sulphide, a substance lethal to most life forms.

(Additional reporting by Reed Stevenson in Seattle)

Source: Reuters

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