For Immediate Release: Sept. 7, 2004 \CA-N-04-97
Contact: Jeff Fontana (530) 252-5332, or Ken Collum (530) 279-6101

SCIENTISTS TO STUDY EARTH'S CRUST BENEATH NW NEVADA, NE CALIFORNIA

Scientists and graduate students from Stanford University will conduct research on the thickness and composition of the Earth's crust under parts of northeast California and Northwest Nevada in tests to begin in mid September.

Under permits issued by the Bureau of Land Management (BLM) Surprise and Winnemucca field offices, the researchers will use over 1,000 portable seismographs and geophones to record seismic waves created by six precisely timed and located underground explosions. The geophysical research will be conducted along a transect through areas managed by the BLM's Winnemucca, Nevada, Field Office, the Surprise, California, Field Office and the Modoc National Forest. Tests are tentatively scheduled for Wednesday or Thursday, Sept. l5 or 16.

The simultaneous explosions will occur at night to reduce interference from background noise. Before detonations, areas will be cleared for safety, and visual and audio alarms will be used to signal the impending shot. Noise from each shot will be a muffled thud sometimes accompanied by a sharp crack similar to a rifle shot. Shots might be heard up to a mile away.

Ground rolls from the detonations will not be felt beyond a few hundred feet. Measurements of the time it takes for the waves from each location to reach the recording instruments will be used to create an accurate picture of the different rock types and structures present deep in the Earth's crust.

Tests will use six boreholes drilled along a roughly east-west line in remote areas north of the Black Rock Desert in northwestern Nevada and into northeast California. All activities will be conducted within existing disturbance along roadways and within a gravel pit. The recording devices will also be placed along existing roads. The data recorders will be retrieved following the detonations and the data transferred to a central computer. All data gathered will be archived and publicly released through an Earthscope data center. Earthscope is a National Science Foundation program that is also providing the latest technology and equipment for the project.

Stanford will also use the project, scheduled to take place before September 15th, to train a group of its undergraduate students in geologic and geophysical techniques required to study the continents. The goal of the project is to increase public appreciation of local geology and expand knowledge of the Earth's crust to help scientists better understand the earthquake hazard in the region.

- BLM -

Surprise Field Office 602 Cressler Street Cedarville, Calif. 96104