Ground Motion Amplification and Seismic Liquefaction: A Study of Treasure Islandand the Loma Prieta Earthquake

摘要

This report is part of the Navy's Earthquake Hazard Mitigation Program. Itdescribes the effects of the Loma Prieta earthquake on Naval Station, Treasure Island focusing on geotechnical comparison of performance of marginal and improved sites. Procedures are presented to estimate settlements and results are compared to observed data. A detailed analysis of ground motion is presented in conjunction with site amplification. It is shown that the site amplification at Naval Station Treasure Island is caused by the stiff Bay Mud layer rather than the loose sand deposits. A comparison is made to the Mexico City earthquake of 1985, which also had high plasticity stiff clays. The high stiffness with shear strain exhibited by these deposits in comparison with normal clays is shown as a function of high plasticity and should be a warning to engineers of potential site amplification of ground motion from distant earthquakes.