LITHOSTRATIGRAPHY AND SHEAR-WAVE VELOCITY IN THE CRYSTALLIZED TOPOPAH SPRING TUFF, YUCCA MOUNTAIN, NEVADA

Technical Report · Mon Mar 20 00:00:00 EST 2006

DOI:https://doi.org/10.2172/886554· OSTI ID:886554

BUESCH, D; STOKOE, K H; SCHUHEN, M

Evaluation of the seismic response of the proposed spent nuclear fuel and high-level radioactive waste repository at Yucca Mountain, Nevada, is in part based on the seismic properties of the host rock, the 12.8-million-year-old Topopah Spring Tuff. Because of the processes that formed the tuff, the densely welded and crystallized part has three lithophysal and three nonlithophysal zones, and each zone has characteristic variations in lithostratigraphic features and structures of the rocks. Lithostratigraphic features include lithophysal cavities, rims on lithophysae and some fractures, spots (which are similar to rims but without an associated cavity or aperture), amounts of porosity resulting from welding, crystallization, and vapor-phase corrosion and mineralization, and fractures. Seismic properties, including shear-wave velocity (V{sub s}), have been measured on 38 pieces of core, and there is a good ''first order'' correlation with the lithostratigraphic zones; for example, samples from nonlithophysal zones have larger V{sub s} values compared to samples from lithophysal zones. Some samples have V{sub s} values that are beyond the typical range for the lithostratigraphic zone; however, these samples typically have one or more fractures, ''large'' lithophysal cavities, or ''missing pieces'' relative to the sample size. Shear-wave velocity data measured in the tunnels have similar relations to lithophysal and nonlithophysal rocks; however, tunnel-based values are typically smaller than those measured in core resulting from increased lithophysae and fracturing effects. Variations in seismic properties such as V{sub s} data from small-scale samples (typical and ''flawed'' core) to larger scale traverses in the tunnels provide a basis for merging our understanding of the distributions of lithostratigraphic features (and zones) with a method to scale seismic properties.

• Research Organization: Yucca Mountain Project, Las Vegas, NV (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: NA
• OSTI ID: 886554
• Report Number(s): NA; MOL.20060419.0213, DC#47445; TRN: US0603995
• Country of Publication: United States
• Language: English

Related Subjects

12 MANAGEMENT OF RADIOACTIVE WASTES, AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS
CAVITIES
CORROSION
CRYSTALLIZATION
EVALUATION
FRACTURES
FRACTURING
HIGH-LEVEL RADIOACTIVE WASTES
MINERALIZATION
NUCLEAR FUELS
POROSITY
TUFF
VELOCITY
WELDING
YUCCA MOUNTAIN
SPENT FUELS