Detailed Geophysical Fault Characterization in Yucca Flat, Nevada Test Site, Nevada
Yucca Flat is a topographic and structural basin in the northeastern part of the Nevada Test Site (NTS) in Nye County, Nevada. Between the years 1951 and 1992, 659 underground nuclear tests took place in Yucca Flat; most were conducted in large, vertical excavations that penetrated alluvium and the underlying Cenozoic volcanic rocks. Radioactive and other potential chemical contaminants at the NTS are the subject of a long-term program of investigation and remediation by the U.S. Department of Energy (DOE), National Nuclear Security Administration, Nevada Site Office, under its Environmental Restoration Program. As part of the program, the DOE seeks to assess the extent of contamination and to evaluate the potential risks to humans and the environment from byproducts of weapons testing. To accomplish this objective, the DOE Environmental Restoration Program is constructing and calibrating a ground-water flow model to predict hydrologic flow in Yucca Flat as part of an effort to quantify the subsurface hydrology of the Nevada Test Site. A necessary part of calibrating and evaluating a model of the flow system is an understanding of the location and characteristics of faults that may influence ground-water flow. In addition, knowledge of fault-zone architecture and physical properties is a fundamental component of the containment of the contamination from underground nuclear tests, should such testing ever resume at the Nevada Test Site. The goal of the present investigation is to develop a detailed understanding of the geometry and physical properties of fault zones in Yucca Flat. This study was designed to investigate faults in greater detail and to characterize fault geometry, the presence of fault splays, and the fault-zone width. Integrated geological and geophysical studies have been designed and implemented to work toward this goal. This report describes the geophysical surveys conducted near two drill holes in Yucca Flat, the data analyses performed, and the integrated interpretations developed from the suite of geophysical methodologies utilized in this investigation. Data collection for this activity started in the spring of 2005 and continued into 2006. A suite of electrical geophysical surveys were run in combination with ground magnetic surveys; these surveys resulted in high-resolution subsurface data that portray subsurface fault geometry at the two sites and have identified structures not readily apparent from surface geologic mapping, potential field geophysical data, or surface effects fracture maps.
- Research Organization:
- United States Geological Survey - Nevada, Henderson, NV
- Sponsoring Organization:
- USDOE National Nuclear Security Administration (NA)
- DOE Contract Number:
- AI52-07NA28100
- OSTI ID:
- 947552
- Report Number(s):
- OF 2008-1346; TRN: US200909%%324
- Country of Publication:
- United States
- Language:
- English
Similar Records
Groundwater Flow Systems at the Nevada Test Site, Nevada: A Synthesis of Potentiometric Contours, Hydrostratigraphy, and Geologic Structures
Sub-crop geologic map of pre-Tertiary rocks in the Yucca Flat and northern Frenchman Flat areas, Nevada Test Site, southern Nevada
Related Subjects
ARCHITECTURE
BOREHOLES
CONTAINMENT
CONTAMINATION
FLOW MODELS
FRACTURES
GEOMETRY
GEOPHYSICAL SURVEYS
GROUND WATER
HYDROLOGY
MAGNETIC SURVEYS
NEVADA TEST SITE
PHYSICAL PROPERTIES
SECURITY
TESTING
VOLCANIC ROCKS
WEAPONS
geophysical
fault characterization
Yucca Flat
Nevada Test Site
Nevada