7.11.2005

Tsunami
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How fast could we react if there was a quake-driven tsunami warning here on the West Coast? The primary threats would seem to be the subduction zone off the West Coast and the Cascade volcanos (Mt. Shasta, Mt. Lassen, Mt. St Helens, Mt. Baker, and especially the bulging ice cream cone of Mt. Rainier. A less prominent, though no less potent threat is the Medicine Hat Volcano which is a large "flat" plateau of lava which could suddenly explode. Geologists think there could be a one-two punch - an earthquake off the coast triggering the eruption inland or the other way around.

SEATTLE (Reuters) - Tales about "Thunderbird" and "Whale" by native tribes along the U.S. West Coast, along with geological clues, point to at least two massive quakes and tsunamis that have hit the area in the last 1,100 years, a researcher said on Monday.

"Native people here were well aware that earthquakes happened and that is reflected in their oral traditions," said Ruth Ludwin, a University of Washington researcher who recently published two papers detailing such folklore.

In one tale, the mythical wind creature "Thunderbird" drives its talons into "Whale's" back and is dragged to the bottom of the ocean, which she said could be interpreted as a tsunami-like event.

The stories were collected from native tribes in northern California, Oregon, Washington and just south of Canada's Vancouver Island.

Ludwin, who collaborated with seismologists, said she began looking into the region's "geomythology" six years ago because of the lack of such data, which can be found in other areas such as Japan and the Indonesian island of Sumatra.

In December, a 9.15 magnitude earthquake erupted off the coast of Indonesia's Sumatra island. The quake, the strongest in 40 years, sent walls of water as high as 33 feet barrelling into 13 Indian Ocean nations and killed 160,000 people. Last month, a major 7.0 magnitude earthquake off the coast of northern California triggered tsunami alerts along most of the U.S. West Coast. The alarm was quickly called off and there were no casualties or damage.

The Cascadia subduction zone, which generates much of the seismic activity in the Pacific Northwest, had at least seven major earthquakes in the last 3,500 years, according to researchers.

One massive earthquake is estimated to have hit the region in 900, while eyewitness accounts from the 19th century point to a huge earthquake and tsunami that hit the area in 1700.

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