1995 nen Hyogoken nanbu jishin ni okeru danso, jishindo, higai ni kansuru chosa kenkyu. (General report on investigations of fault, earthquake motion and damage due to the 1995 Hyogoken-nanbu Earthquake).

摘要

The results of various investigations and examinations conducted concerning the 1995 Hyogoken-nambu earthquake are presented. Along the boundary surface between the granite and Osaka group, and in the Osaka group, accumulated displacements and flexural structures are found, supposedly attributed to faulting, by high-density electric prospecting and underground radar prospecting near the Nojima earthquake fault. Displaced structures in the unconsolidated covering layer are detected to the depth of 10-odd meters. Displacement of ground water due to earthquake is different between the shallow and deep layers, which can be explained by a simplified model. The dynamic stress drop in the main shock is equal to the maximum (Delta-gamma) value of each of the aftershocks, and there exists a certain ceiling over the Delta-gamma dependence on the earthquake moment. The maximum acceleration of the earthquake motion estimated from waveforms in the rock is approximately 300 gals, which probably results from the concentration in one direction of the inputted energy wherein long period components are dominant. The newly developed nonlinear analysis technique simulates the attenuation and amplification of acceleration accompanied by liquefaction, and the buckling behavior of bridge columns may be explained by this technique. 72 refs., 84 figs., 6 tabs.