S060-0003
Ground Motion Simulations in the Yucca Flat Basin from Earthquake Scenarios on the Yucca Fault
Wednesday, 16 December 2020
Poster
Arben Pitarka, Lawrence Livermore National Laboratory, Livermore, CA, United States, Cleat Philip Zeiler, Mission Support and Test Services, Defense Nuclear Nonproliferation, North Las Vegas, NV, United States, Arthur J Rodgers, Lawrence Livermore National Laboratory, Atmospheric, Earth and Energy Division, Livermore, CA, United States, Lance Prothro, National Security Technologies, Las Vegas, NV, United States and Michelle Scalise, University of Nevada Reno, Reno, United States
Abstract:
Deterministic broad-band simulations (0-5Hz) were conducted to estimate ground motion in the Yucca Flat basin from M6.6 scenario earthquakes on the Yucca Fault, which crosses the Nevada National Security Site. The simulations were performed on high performance computers at the Lawrence Livermore National Laboratory using a 3D wave propagation finite-difference method and a newly developed seismic velocity model based on the geological framework model of the site. Correlated stochastic velocity variations added to the velocity model were used to produce the observed short-period basin wave scattering. We used a hybrid method to generate kinematic rupture models of normal faulting on curved listric fault surfaces that represent plausible geometries of the Yucca fault. The major emphasis of our study was on the quantification of epistemic uncertainty in ground motion characteristics due to variations in the fault curvature at depth.
The simulation results show that the amplification behavior of the Yucca Flat basin is controlled by the interactions of basin geometry with faulting characteristics, including rupture initiation location and fault curvature. The highest ground motion is observed along the fault and in the hanging wall region. Moreover near-fault areas with deep sediments are characterized by large ground motion amplifications. Comparisons with Ground Motion Prediction Equations for normal faulting were used to demonstrate that the simulated amplification is driven by the fault curvature at depth, and it is more pronounced in the period range 1-3 s. In addition to the rupture models’ characteristics, maps of peak ground displacement, velocity, acceleration, and spectral acceleration response will be shown to illustrate the link of simulated ground motion spatial variability to basin response and fault geometry.
This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under contract DE-AC52-07NA27344. Lawrence Livermore National Security, LLC. LLNL-ABS-812687. This work was done by Mission Support and Test Services, LLC, under Contract No. DE-NA0003624 with the U.S. Department of Energy. DOE/NV/03624-0824.
