In-situ pore water pressures and ground motions during the 1987 Chiba-Toho-Oki earthquake

摘要: After the Owi Island observation program was terminated, a new recording station established at Sunamachi, Tokyo Bay, in 1986 to monitor pore water pressures and accelerations during earthquakes. On December 17, 1987, an earthquake of magnitude 6.7 shook area Bay set instruments picked up motions pressures. The maximum ground surface acceleration recorded 122 gal pressure rise sandy deposits depths 7 13 m 6% 14% mean effective confining pressure. basis laboratory test results performed previously on undisturbed samples, estimate made that might have been produced deposit by seismic shaking with peak gal. estimated values were shown be satisfactory agreement those monitored earthquake.