STUDY ON ANISOTROPY OF EARTH RESISTIVITY IN THE EPICENTRAL AREA OF HAIYUAN M8.5 EARTHQUAKE OCCURRED IN 1920

Through the circular electric sounding in the epicentral area of Haiyuan M8.5 earthquake we found that there is obvious anisotropy of earth resistivity on the fracture zone of faults.Perpendicular to the strike of fault shows high electrical property and along the strike of fault shows low electrical property.Based on the difference in electrical property, the characteristic of surface deformation above fault is discussed.The results show that circular electrical sounding is significant to the study of stratum characteristic near surface.