Technical basis and parametric study of ground motion and surface rupture hazard evaluations at Yucca Mountain, Nevada
The hazards of ground motion and primary fault rupture at Yucca Mountain, Nevada, were evaluated for earthquake occurrence models consisting of faults and background seismicity. This investigation estimated seismic hazard sensitivity to geologic parameters. Few Quaternary slip-rate data are available for faults in the site vicinity. Late Neogene apparent vertical slip-rates exhibit a correlation with mapped fault length, and this suggested the use of slip-rate/fault-length correlations as a device for assigning seismicity to faults. Correlations with power-law exponents of 1, 2, and 3 were used to construct models with varying relative activities of short and long faults. Seismicity models were constructed with alternate rupture-magnitude relations and varying b-values. Background seismicity was evaluated by subtracting fault-related activity from the historic regional activity. The calculated ground motion hazard was dominated by the Paintbrush Canyon and related faults and by background seismicity and was most sensitive to the assumed slip-rate function. Varying other parameters, including the regional seismic quality factor (Q) in the attenuation function, had relatively little effect. Surface rupture hazard was modeled using a joint probability for surface rupture displacement, length, and rupture radius exceedances, together with the fault-related earthquake recurrence models. The surface rupture hazard calculated for the Paintbrush Canyon fault, and related primary faults in the site vicinity, was most sensitive to the assumed slip-rate function. Surface rupture hazard was relatively insensitive to the (downdip) fault width.
- Research Organization:
- URS/John A. Blume and Associates, Engineers, San Francisco, CA (United States); Sandia National Labs., Albuquerque, NM (United States)
- DOE Contract Number:
- AC04-76DP00789
- OSTI ID:
- 60167
- Report Number(s):
- SAND--86-7013; ON: DE88000265
- Country of Publication:
- United States
- Language:
- English
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