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Vertical Distribution of Peak Subsurface Horizontal Earthquake Accelerations.
Chen, P. C.
National Science Foundation, Washington, DC. Directorate for Engineering., August 1985, 41 p.
192 sets of Japanese free-field peak horizontal accelerations (PHA) of subsurface earthquake motions recorded at 20 sites were studied to determine the vertical distribution with depth of peak subsurface horizontal accelerations. These sets were divided into five groups according to their various peak ground-surface horizontal accelerations. The site were classified as either soft or medium. Mean values of PHAs at various depths for five acceleration groups were computed for soft and medium sites. Amplification factors of the mean PHAs between the ground surface and the depth at which the blow count number, N, first reaches a value of 50 and that between the ground surface and depths at which N is less than 50 were studied. These amplification factors and medium sites of the mean PHAs between the ground surface and the depth at which N first reaches 50 were compared with the calculated site amplifications using average normalized horizontal acceleration response spectra.
Depth; Seismic waves; Subsurface investigations; Peak horizontal accelerations; Seismic prospecting; Seismology; Earth movements; Acceleration (Physics); Amplification; Japan; Earthquakes