Geologic and Geophysical Characterization Studies of Yucca Mountain, Nevada, A Potential High-Level Radioactive-Waste Repository

The safe disposal of high-level radioactive wastes is one of the most pressing
environmental issues of modern times. At present, most of these materials are
being stored under temporary conditions at many of the individual nuclear power
plants where they were produced. In recognition of the need for permanent
waste storage, Yucca Mountain in southwestern Nevada has been investigated by
Federal agencies since the 1970's as one of the Nation's potential geologic
disposal sites. In 1987, Congress selected Yucca Mountain for an expanded and
more detailed site characterization effort, and a broad multidisciplinary
program of studies was developed by the U.S. Department of Energy to further
evaluate the suitability of the mountain as a safe and permanent underground
disposal facility. The scope and objectives of the many kinds of
investigations to be pursued were guided in large measure by regulations
governing the siting of geologic repositories for high-level radioactive
wastes that were issued by the U.S. Nuclear Regulatory Commission (Code of
Federal Regulations 10CFR60) and supplmented by further requirements set forth
by the U.S. Department of Energy (Code of Federal Regulations 10CFR960).

As an integral part of the planned site-characterization program, the U.S.
Geological Survey began a series of detailed geologic, geophysical, and
related investigations designed to characterize the tectonic setting, fault
behavior, and seismicity of the Yucca Mountain area. A broad goal was to
provide essential data for assessing the possible risks posed by future
seismic and fault activity in the area that may affect the design and
long-term performance, and the safe operation, of the potential surface and
subsurface repository facilities.

The results of 13 of the many studies undertaken to increase understanding of
the tectonic environment of Yucca Mountain and the adjacent area are presented
in this report.

[Summary provided by the USGS.]