Historical Overview |
Nuclear Testing at the Nevada Test Site |
The Nevada Test Site (NTS) was
established in 1951 as a continental location for testing nuclear
devices (Allen and others, 1997, p. 3). Located approximately 100 miles northwest of Las
Vegas, the NTS lies within the Nellis Air Force Range
and is managed and supported by the U.S. Department of Energy. Originally known as the “Nevada Proving Ground,” the NTS
hosted more than 920 nuclear detonations (U.S. Department of Energy,
2000) within the Yucca Flat, Pahute Mesa, Frenchman Flat, Rainier Mesa including Aqueduct Mesa,
Climax Stock, Shoshone Mountain, Buckboard Mesa,
and Dome Mountain testing areas.
Underground detonations were typically
emplaced in vertical drill holes (shafts), although several were tunnel
emplacements and some were crater emplacements. Of the testing areas, Yucca Flat
and Pahute Mesa were most extensively used.
On November 29, 1951, the first underground nuclear detonation, named Uncle, was conducted at the NTS as a crater type, weapons experiment in Area 10 of Yucca Flat (or Yucca Valley, as it is also known). The first “deep” underground detonation, named Pascal-A (U-3j), was conducted on July 26, 1957 as a shaft type, safety experiment in Area 3 at a depth of 152 m (499 ft) in an uncased (unstemmed) borehole (Allen and others, 1997, p. 3). At Pahute Mesa, the first underground nuclear detonation, named Palanquin, was conducted on April 14, 1965 as a crater type, Plowshare experiment in Area 20 at a depth of 86 m (281 ft). Also at Pahute Mesa, the first Joint Verification Experiment between the United States and the Union of Soviet Socialist Republics was conducted with the Kearsarge detonation on August 17, 1988 at a depth of 616 m (2,020 ft). Nearly 41 years after the first nuclear test at the NTS, the last weapons related experiment was conducted in Area 3 at Yucca Flat. The Divider detonation was conducted on September 23, 1992, just prior to the signing of a one-year moratorium on underground nuclear testing by President Bush in late 1992. Subsequently, the newly elected President Clinton extended this moratorium and later signed the Comprehensive Nuclear Test Ban Treaty prohibiting all underground nuclear testing. |
Surface Effects Mapping at the Nevada Test Site |
| The USGS became involved with
the nuclear testing program in 1957 as part of an aggressive effort to
map the geology of the NTS at a scale of 1:24,000 (Garcia, 1997). This
mapping effort not only provided the first detailed geologic maps of
the area, but also gave scientists an opportunity to explore the
containment characteristics of the geologic environment. Carothers
(1995), for example, discusses how the geologic environment became a
test parameter for nuclear testing. These early experiments revealed
that geology and hydrology were important site-placement
characteristics, and conversely, advanced our understanding of the
geology of the NTS. Supported by the U.S. Atomic Energy Commission (AEC),
the U.S. Energy Research and Development Administration (ERDA), and
the U.S. Department of Energy (DOE), the USGS began an extensive
research program to evaluate the geophysical, hydrological, and
geological characteristics of the NTS. One component of this work focused
on mapping the surface effects caused by underground nuclear testing.
Post-detonation surface effects maps were produced using field and aerial-photo mapping techniques and recorded in several types of USGS publications, reports, and memorandums. Features mapped included surface cracks; collapse sinks (and craters); various types of fault movements; pressure ridges; and reactivated features. Garcia (1997), in what has informally become known as a “How-To Publication” on surface effects mapping, explains in detail the procedures used to prepare these maps. Ultimately, a final “crack map,” as they are often called, was prepared in ink on stable-based drafting film for use in the USGS documents. The final crack maps were ultimately stored by the USGS in map files at the Denver Federal Center in Lakewood, Colorado. This CD-ROM map archive is the product of the latest phase of surface effects map work by the USGS. The digital reproduction of the original surface effects maps began as a pilot project, which was implemented to evaluate methods for digitally duplicating and permanently storing the original, hand-drawn maps. A Geographic Information System was used because of its abilities to store map data with associated attribute information, and because GIS provides the needed methods to query, retrieve, update, and display these data as required. Simply stated, the goals of this project were: (1) To reproduce the original, hand-drawn surface effects maps in digital format so that they could be directly used in computer-aided research, management, and readiness activities, and (2) To preserve, in a permanent digital archive, the many years of painstaking surface effects mapping that was done at the NTS. The documentation, data tables, and maps presented in this archive, and in prior published reports by the author on Yucca Flat (Grasso, 2000), Pahute Mesa (Grasso, 2001), and other testing areas (Grasso, 2003) provide further information and views of the surface effects maps contained in the GIS Surface Effects Map Archive.
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