Threat of quakes appears greater

Thursday, May 1, 2003 | 9:39 a.m.

A new study shows that the Las Vegas Valley's risk of damage from a major earthquake could be double previous estimates.

Catherine Snelson, assistant geoscience professor at the University of Nevada, Las Vegas, said she is continuing to map the valley, which she said appears deeper than previously believed, a factor that could increase the magnitude of quakes. That could lead to more destruction of life and property in an earthquake of magnitude 6.5 to 7 on the Richter scale.

At least eight faults around the valley could produce a major quake, she said.

Seismologists and engineers from UNLV, the University of Nevada, Reno, and Lawrence Livermore National Laboratory in Northern California are analyzing earth movements from quarry blasts and a chemical explosion at the Nevada Test Site captured on 12 monitors placed around the valley.

"We are at a greater seismic risk than we thought," Snelson said Wednesday from Puerto Rico, where she presented preliminary results at a geological meeting sponsored by the Seismological Society of America.

"If we had an earthquake in the valley's basin, it could be devastating."

There is no way to predict when a "big one" will occur, she said.

"It could happen today, in a year, in 10 years, in 1,000 years, we just don't know when the next one will come," Snelson said.

As Snelson continues her studies, she said she hopes to educate Las Vegas residents to prepare for a temblor.

Seismologist Jim O'Donnell, who worked with Snelson on the project, said a major quake could be expected to cause $11 billion in property damages and kill 50 to 100 people in Las Vegas.

O'Donnell said the research also indicates increased risk from a process called amplification.