HR: 09:10h
AN: S41C-05 INVITED     [Abstracts]
TI: Seismic Wave Amplification in Las Vegas: Site Response and Empirical Estimates of Ground Motion
AU: * Rodgers, A
EM: rodgers7@llnl.gov
AF: Energy and Environment Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94551 United States
AU: McCallen, D
EM: mccallen2@llnl.gov
AF: Energy and Environment Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94551 United States
AU: Tkalcic, H
EM: tkalcic1@llnl.gov
AF: Energy and Environment Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94551 United States
AU: Wagoner, J
EM: wagoner1@llnl.gov
AF: Energy and Environment Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94551 United States
AU: Louie, J
EM: louie@seismo.unr.edu
AF: Nevada Seismological Laboratory, University of Nevada, Reno, NV 89557
AU: Anderson, J
EM: jga@seismo.unr.edu
AF: Nevada Seismological Laboratory, University of Nevada, Reno, NV 89557
AU: Luke, B
EM: bluke@ce.unlv.edu
AF: Civil Engineering Department, University of Nevada, Las Vegas, NV 89154 United States
AU: Snelson, C
EM: csnelson@unlv.nevada.edu
AF: Geoscience Department, University of Nevada, Las Vegas, NV 89154 United States
AU: Taylor, W
EM: wjt@unlv.nevada.edu
AF: Geoscience Department, University of Nevada, Las Vegas, NV 89154 United States
AB: This presentation will summarize a multidisciplinary effort to understand seismic wave amplification in Las Vegas Valley. The project involves weak motion recording and analysis, geotechnical and seismic refraction field studies, geologic and lithologic interpretation and model building. We will provide a brief overview of the project, then focus on specifics of seismic wave amplification including observations and interpretations. We analyzed recordings of nuclear explosions from the Nevada Test Site (NTS) and regional earthquakes to estimate site response in Las Vegas. An empirical transfer function method was used to transform ground motion time-series at one (reference) station to other stations, using frequency dependent site response curves in the band 0.2-5.0 Hz. The method transforms the time-series to the frequency domain by Fast Fourier transform, multiplies the amplitude spectrum by the site response curve and inverse FFT's back to the time domain. The approach is validated by the ability to predict horizontal component S-wave ground motion measures, such as peak and rms ground velocities and accelerations. We then can provide empirical estimates of ground motion for a wider distribution of sites in Las Vegas. Frequency dependent amplifications (site response) and peak ground motions are strongly correlated with measures of shallow shear-wave (geotechnical) velocities. Details of the geotechnical measurements and models will be presented in a companion presentation. This work was performed under the auspices of the U.S. Department of Energy by University of California Lawrence Livermore National Laboratory under contract No. W-7405-Eng-48.
DE: 7223 Seismic hazard assessment and prediction
DE: 7212 Earthquake ground motions and engineering
SC: Seismology [S]
MN: 2004 AGU Fall Meeting