Studying the movement of rock and earthquakes

Scientists are carefully studying the geology of Yucca Mountain, Nevada, and its surrounding region to determine whether or not spent nuclear fuel and high-level radioactive waste could be isolated safely deep below the mountain’s surface. These studies began more than 15 years ago. Many studies and analyses providing information about the potential for earthquakes have been completed. (Additional studies may be needed.)¹

Engineering analyses are now under way to ensure that repository facilities are designed to mitigate the effects of potential earthquakes.

Earthquakes occur when cracks or fissures in the Earth’s surface, called faults, move.

Major trenching programs near Yucca Mountain have studied fault movement during the past two million years. Geologic study of the deposits exposed in these trenches and minerals found in fault zones provided evidence of how frequently and how much faults have moved in the past. This information, together with information from historical and contemporary earthquake catalogues from the Southern Great Basin Seismic Network,² was used to analyze the potential for earthquakes at Yucca Mountain. It also appears that the potential for earthquake damage to an underground repository is very slight.

Experience with earthquakes throughout the world has shown that underground structures can withstand the ground motion generated by earthquakes. And, in actual tests at the Nevada Test Site, mine tunnels have withstood ground motion from underground nuclear explosions that are greater than any ground motion anticipated at or near Yucca Mountain. Repository facilities at the surface also can be designed to safely withstand earthquake effects.

1 For additional information on earthquakes, see the Yucca Mountain Site Description, section 12.3, Seismicity and Seismic Hazards.

2 The Southern Great Basin Seismic Network is a network of seismic monitoring stations that collect earthquake data from 29 stations located within 65 km of Yucca Mountain. The data are collected and analyzed at the Seismological Laboratory at the University of Nevada, Reno.