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Koji Yamada and Masanori Horike
Inference of Q-values below 1 Hz from borehole and surface data in the Osaka Basin by three-component waveform fitting
Bulletin of the Seismological Society of America (August 2007), 97(4):1267-1278
Abstract: Index Terms/Descriptors: Latitude & Longitude:
GeoRef, Copyright 2007, American Geological Institute. Abstract, Copyright, Seismological Society of America. Reference includes data from GeoScienceWorld, Alexandria, VA, United States
The quality factor of the shear waves Q s below 1 Hz in the Osaka sedimentary basin, Japan, is inferred from borehole earthquake-motion recordings and surface earthquake-motion recordings by three-component waveform fitting. Assuming quality factor of S waves Q s to be a function of the frequency f and the shear-wave velocity V s in meters in the form AV s f n , the waveform fitting of borehole data reveals that coefficient A is approximately 0.24, and exponent n is less than or equal to zero. To verify Q s -values from borehole data and, if possible, to confine Q s -values to a narrow range, we infer the Q s -values from surface earthquake-motion recordings by fitting them with earthquake motions simulated by the finite-difference method. It indicates that Q s -values are negatively frequency dependent and that the lower limit of Q s -values is approximately 0.24V s f (super -1) .
algorithms; Asia; boreholes; earthquake prediction; earthquakes; elastic waves; Far East; frequency; geologic hazards; ground motion; guided waves; Honshu; Japan; Love waves; models; Osaka Basin; Osaka Japan; Q; risk assessment; seismic risk; seismic waves; seismographs; surface waves; three-component seismographs; three-dimensional models; waveforms
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