Earthquake prediction Ⅳ:electromagnetic method
ZHAO Yong-hong;XIAO Yan-jun;WANG Hang;ZHANG Qiong;Department of Geophysics,Peking University;
Electromagnetic method is one of the earthquake prediction methods which is in the preliminary stage. The main process of this method is to acquire the electromagnetic data( electric components,electrical resistivity,magnetic components or the frequency of electromagnetic wave,etc.) in the areas that are covered with observation instruments. The data was processed to extract the electromagnetic anomaly caused by seismic activity. The earthquake prediction including time,location and magnitude of the earthquake are suggested by analyzing the electromagnetic anomaly.Many experiments and studies showed that electromagnetic method for earthquake prediction is not effective yet,and its precision and the range it can predict are extremely limited. Finding out the physical mechanism of the electromagnetic anomalies before the earthquake and its relation with the three elements of earthquake are the main tasks and it will be a big step for earthquake prediction. In this paper, we reviewed the development and prospects of electromagnetic method in earthquake prediction all around the world from three aspects: the basic experimental results of the rock fracture process,the field observation records and the analysis as well as the evaluation of the existing electromagnetic methods.