Crustal Stress Measurement and Earthquake Prediction

Abstract

Since 1978, as part of the Japanese Earthquake Predition Plan, Universities, the National Research Center for Disaster Prevention, and the Geological Survey of Japan have been making efforts to measure crustal stress. The results of in situ stress measurements make it clear that the stress orientation almost exactly coincides with the tectonic stress field inferred from other earthscience investigations. In earthquake prediction, it is also essential to grasp the strain energy accumulation in a restricted areas. An attempt has therefore been made to reduce the stress values at various depth to those at a standard depth using a stress depth gradient in order to compare the stress magnitudes at each measuring point. The standardization of measurãƒÂ¯ã‚¿ã‚½ing conditions makes discussion of regional distribution of stress magnitude possible. Furthermore, the manner of representation, that is, stereographic projection of the maximum shear plane, has been introduced for the illustration of the 3-dimensional stress state at the measuring site. © 1985, The Geodetic Society of Japan. All rights reserved.