Factors Affecting Seismic Velocity in Alluvium
- National Security Technologies, LLC. (NSTec), Mercury, NV (United States)
Yucca Flat at the Nevada National Security Site has been selected as the Source Physics Experiment (SPE) Dry Alluvium Geology Phase II site. The alluvium in this part of Yucca Flat is typical of desert basin fill, with discontinuous beds that are highly variable in clast size and provenance. Detailed understanding of the subsurface geology will be needed for interpretation of the SPE seismic data. A 3D seismic velocity model, created for Yucca Flat using interval seismic velocity data, shows variations in velocity within alluvium near the SPE Phase II site beyond the usual gradual increase of density with depth due to compaction. In this study we examined borehole lithologic logs, geophysical logs, downhole videos, and laboratory analyses of sidewall core samples to understand which characteristics of the alluvium are related to these variations in seismic velocity. Seismic velocity of alluvium is generally related to its density, which can be affected by sediment provenance, clast size, gravel percentage, and matrix properties, in addition to compaction. This study presents a preliminary subdivision of the alluvial strata in the SPE Phase II area into mappable units expected to be significant to seismic modeling. Further refinements of the alluvial units may be possible when seismic data are obtained from SPE Phase II tests.
- Research Organization:
- Nevada National Security Site/National Security Technologies, LLC (United States)
- Sponsoring Organization:
- USDOE Office of Defense Nuclear Nonproliferation Research and Development (NA-22)
- DOE Contract Number:
- DE-AC52-06NA25946
- OSTI ID:
- 1506119
- Report Number(s):
- DOE/NV/25946-2692
- Resource Relation:
- Conference: American Geophysical Union Fall meeting, December 14-18, San Francisco http://fallmeeting.agu.org/2015/abstract-submissions/
- Country of Publication:
- United States
- Language:
- English
Similar Records
Geologic Framework Model for the Dry Alluvium Geology (DAG) Experiment Testbed Yucca Flat, Nevada National Security Site
Making sense of the mixed alluvium in the Yucca Flat basin