THE EFFECT OF CRACKING ON REMANENT MAGNETIZATION OF ROCKS——IT'S IMPLICATION TO EARTHQUAKE PREDICTION
HAO JIN-QT HUANG PING-ZHANG ZHOU JIAN GUO(Institute of Geophysics ,SSB Beijing 100081)
In this study, the changes of remanent magnetization in rocks during cracking process are investigated and its nature is found for the first time to be related with closing of existed micro-cracks at lower applied pressure and opening of newly-developing microcracks at higher pressure, respectively. The later is rather obvious prior to the failure of rock samples. These phenomena imply that the compactness and stress-strain relation of medium in the seismogenic zone should be noticed and the variation of local geomagnetic field connected with fore-shocks should be searched in the study on geomagnetic precursors.