Geologists plan to detonate explosives in Vegas seismic study

LAS VEGAS (AP) -- Geologists at the University of Nevada, Las Vegas, are planning a large-scale experiment that will include detonating more than 7,500 pounds of explosives.

Charges will be set off at 10 spots throughout the Las Vegas area next week in an effort to create seismic waves underground. The study will look at how earthquake fault lines work and where they are located.

"Pretty much nothing has ever been undertaken like this in the valley before," said Cathy Snelson, a UNLV geologist. "We are trying to really get a detailed view of the basin itself."

Construction crews will begin drilling holes this week in preparation for the experiment. Explosives will be placed in holes 150 feet underground and set off late at night to avoid people who may be wandering around the sites.

Some 825 seismic instruments buried in the ground at various locations will record the activity.

"Some residents will be aware of the explosions because there are a few sites that are near homes and buildings," said Joe Dodd, operations manager for Sanders Construction in Henderson, the company that will help set up the experiment.

Dodd and Snelson said no foundations of buildings would be damaged by the explosions, and area residents are not likely to be bothered by the explosions because the holes will be plugged with clay and gravel to muffle the sound.

Setting up for the experiment took months because UNLV was required to notify residents within about 1,000 feet around the blast sites, Dodd said.

The university also got permission from the Bureau of Land Management and property owners to do the experiments. After that, the construction company obtained approvals from area fire departments to conduct the blasts, Dodd said. The construction company is carrying a $5 million insurance policy on the experiment in case anything goes wrong.

So far, eight fault lines have been detected throughout the Las Vegas basin, but not much is known about where they are or how they might shake during a major earthquake. Geologists do know the fault lines are deeper in the center and then trail off at the edges, Snelson said.

"We don't have any historic research of when the last major event happened," she said. "So there's no telling when the next earthquake will be."

Snelson said the area has a potential for a 6.5- or 7.0-magnitude quake.

"If everything works well and all of my blasts go off, we should have some good data hopefully," she said.