LOTUNG DOWNHOLE ARRAY .1. EVALUATION OF SITE DYNAMIC PROPERTIES

The Lotung large-scale seismic test (LSST) site in Taiwan was instrume nted in 1985 with an array of downhole and surface accelerometers, by the Electric Power Research Institute (EPRI), Pale Alto, Calif., and t he Taiwan Power Company (TPC), Taipei, Taiwan. A total of 18 earthquak es were recorded during the period 1985-86. Correlation and spectral a nalyses of the recorded downhole accelerations are performed to evalua te shear wave propagation characteristics, variation of shear wave vel ocity with depth, and site resonant frequencies and modal configuratio ns. A shear-beam model, calibrated by the identified site properties, is found to represent the site dynamic response characteristics over a wide frequency range. In a companion paper, strong-motion earthquake records are utilized to investigate the Lotung site large-strain soil response characteristics.