Earthquake, tsunami risk investigated at Lake Tahoe

8:30 PM, Aug 29, 2012

Written by

Jeff Maher

Lake Tahoe

(Poster's note: Tahoe looks an awful lot like Crater Lake, OR. oops!)

TAHOE CITY, CA - Is Lake Tahoe due for a big earthquake? If so, will a large tsunami follow? That's the question a research team is literally digging to answer.

The team is using advanced technology to collect ancient evidence, including core samples from the Lake's deepest points.

This is an average geological expedition, then again, Lake Tahoe is not an average place.

"We're just about to go out and do some water column sampling." Professor Ross Powell said as the team was getting ready to head out from the shore.

The research team, made up of geologists from the California Geological Survey, Northern Illinois University and the University of Nevada-Reno, are on a mission to find out the potential effects of a large-scale earthquake hitting the Lake and what kind of tsunami the lake could produce.

Some of the drilling technology the team will use is being tested at Lake Tahoe for an upcoming expedition in Antarctica, which will investigate how life under the ice is being impacted by global warming.

"We're trying to characterize what would happen in a larger event of that size, the six to seven range, the ground would shift under the lake 10 to 20 feet and that would generate wave that would be tens of feet high." California Geological Survey's Gordon Seitz said.

Tens of thousands of years ago, a massive landslide produced a wave that was modeled to be 100 feet high. The last major earthquake in Lake Tahoe, of about a 7.0 magnitude, was about 500 years ago.

There are at least two major fault lines that run beneath Lake Tahoe and they were discovered only recently. There have also been several small scale earthquakes measured in the Tahoe area over the past year.

But the question is, if and when the big one hits, what will happen to the town itself?

"Because the lake is so deep, it's sort of unique compared to other lakes in that it generates waves that may be more hazardous than the ground actually shaking from the earthquake," Seitz explained.

Already, researchers have retrieved soil samples from deep beneath the lake's surface. One sample came from a depth of 500 feet, and they plan to dig further down. The contents inside will give a lot of history, but more importantly, a look at what the future could bring to one of Northern California's biggest tourist attractions.

"There certainly is potential and one of the big questions is, what the timing of that big potential is and the magnitude and that's what the survey is trying to assess," Powell said.

Up to this point, people living in Tahoe are typically not warned about any risk of tsunamis. But researchers said based on the latest findings of those fault lines, warnings will be posted on signs and on homeowner insurance policies in the weeks to come.

News10/KXTV