Comparison of phase velocities from array measurements of Rayleigh waves associated with microtremor and results calculated from borehole shear-wave velocity profiles

作者：Hsi‐Ping Liu, David M. Boore, William B. Joyner, David H. Oppenheimer, Richard E. Warrick, Wenbo Zhang, J. C. Hamilton, Leo Brown · 发表于：Antarctica A Keystone in a Changing World · 年份：2000 · DOI：10.3133/ofr00216 · 被引用次数：1 · 研究领域：Seismic Waves and Analysis、Geophysics and Sensor Technology、Advanced Fiber Optic Sensors

Shear-wave velocities (V5 \ which are widely used for earthquake ground-motion site characterization studies, are now largely obtained using borehole methods. Drilling holes, however, is expensive. Surface methods are less expensive for obtaining V5 information, but not many comparisons with direct borehole measurements have been made. Because different assumptions are used in data interpretation of each surface method, and because public safety is involved in site characterization for engineering structures, it is important to validate the surface methods by additional comparisons with borehole measurements. We compare results obtained from a particular surface method (array measurement of surface waves associated with microtremor) with results obtained from borehole methods. Using a ten-element nested-triangular array of 100-m aperture, we measured surface-wave phase velocities at two California sites, Garner Valley near Hemet and Hollister Municipal Airport. The Garner Valley site is located at an ancient lake bed where water-saturated sediment overlies decomposed granite on top of granite bedrock. Our array was deployed at a location where seismic velocities had been determined to a depth of 500 m by borehole methods. At Hollister, where the near-surface sediment consists of clay, sand, and gravel, we determined phase velocities using an array located close to a 60-m deep borehole where downhole velocity logs already exist. Because we want to assess the measurements uncom...