Tahoe Tsunami Risk

Beautiful Lake Tahoe, which straddles the border between California and Nevada, is one of the world's deepest freshwater lakes - plunging 1,600 feet below the surface in some places.

The lake's deep blue waters cover a fault basin that is prone to earthquakes and landslides.  A team of researchers has found that large, magnitude 7 quakes occur here about every 3,000 years.

Earthquakes of this size could unleash tsunami waves.  Rising from 6 to 30 feet high, such waves would likely slosh back and forth across the lake, causing considerable damage to communities on the lakeshore, said Graham Kent from the Scripps Institution of Oceanography.

"There are thousands of people on the beaches here in the summertime, so it's important to find out more about the history of such events in the area," said Kent.

To probe the lake's geologic past, Kent and his colleagues used a device called CHIRP, which bounces beams of acoustic signals off of the lake floor.  The scientists augmented this data with analyses of sediment cores extracted from the lake bottom.

The information was used to draw up a 60,000-year record of fault movement under Lake Tahoe. The team's methods and results are described in the May issue of the journal Geology.

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-- LiveScience Staff

Credit: UC Davis