Scientists Report Quakes At Site of Proposed Nuclear Waste Store

Wednesday, Oct. 30, 1996 | 11:59 a.m.

The tremors were recorded at and around Yucca Mountain, 100 miles northwest of Las Vegas, since May 1995, although none was strong enough to damage property or threaten lives, the seismologists said at the national convention of the Geological Society of America.

But scientists are investigating whether the earthquakes indicate an instability that would make Yucca Mountain unsuitable for storing nuclear wastes from military warheads and municipal power plants.

The research is continuing because the results to date have been inconclusive, researchers said.

Ken Smith of the University of Nevada-Reno and others said the earthquakes measured over the past 18 months did not exceed magnitude 0.72 on a new and very sensitive network of quake sensors. People don't notice earthquake motions or see their dishes rattle until the tremors approach magnitude 3.0.

"These are indeed very small earthquake sources," Smith said. "What they mean in terms of the overall seismotectonics of the Yucca Mountain is debatable."

The Department of Energy has spent $4 billion and tunneled 3.5 miles into Yucca Mountain for testing. If the site is approved, the DOE plans to build up to 117 miles of tunnels within the mountain and its surrounding valleys to store canisters of nuclear waste.

Nevada officials have been fighting the respository since 1980.

Yucca Mountain's seismic stability is a crucial consideration because the plutonium-based wastes would remain dangerous for thousands of years. Even tiny earthquakes must be analyzed to determine the site's geologic safety over many generations, researchers said.

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