Reconnaissance seismic refraction studies at Calico Hills, Wahmonie, and Yucca Mountain: southwest Nevada Test Site, Nye County, Nevada
Reconnaissance refraction surveys consisting of a total 5 spreads were conducted in the Calico Hills, Wahmonie, and Yucca Mountain areas, southwestern Nevada Test Site (NTS). Data from Calico Hills and Wahmonie are generally high in quality; data from Yucca Mountain are for the most part low in quality. At Calico Hills and Wahmonie, special attention was focused on the possible occurrence of a major intrusive body at depth. At Calico Hills this occurrence is supported by an inferred dome-shaped velocity interface, possibly associated with the roof of an altered phase of argillite. however, if an intrusive body is present, its top must be buried deeper than 3 km or it must be so pervasively altered that its velocity is similar to that of the calcareous argillite encountered at the bottom of drill hole UE 25a-3. At Wahmonie, the seismic data suggest the occurrence of a massive lenticular unit within 60 m of the ground surface, probably consisting of argillite but possibly consisting of intensively altered intrusive rock. At Yucca Mountain, preliminary interpretations of the most reliable data suggest the occurrence of a major, steeply inclined velocity interface 500 m from the southwest end of the Yucca C spread. This interface may represent a major fault or erosional feature separating the Topopah Spring and Tiva Canyon Members with Paintbrush Tuff at depth. This interface is 800 m east of a previously mapped fault. On the basis of poor-quality data obtained at Yucca Mountain, the subsurface velocity distribution appears to be complex. For example, one spread near drill hole UE25 a-1 suggests not only a much thicker section of Tiva but also that this material is down thrown in the valley. This may suggest faulting with throws exceeding 100 meters or an equivalent erosional feature.
- Research Organization:
- US Geological Survey, Denver, CO (United States)
- DOE Contract Number:
- AI08-78ET44802
- OSTI ID:
- 59640
- Report Number(s):
- USGS-OFR-82-478; ON: DE83005619
- Resource Relation:
- Other Information: DN: Portions of document are illegible. Printed copy available until stock is exhausted; PBD: 1982
- Country of Publication:
- United States
- Language:
- English
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