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.
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