A PRIMARY STUDY OF GEORESISTIVITY CHANGE AT XI'AN STATION

This work is a primary study of the georesistivity changes at Xi'an station. The results show that the georesistivity change at Xi'an station was not caused by change of underground water level or other disturbances. And no corresponding earthquake occurred during the anomalous period. It was an anomalous change without earthquake. The directions of main compres-sive stress obtained by relative change of georesistivity at Xi'an station coincincide with those obtained by ground fissure and the source mechanism solutions of small earthqukes, and are almost consistent with the direction of the regional stress field within the area. The results also show that the georesistivity change at Xi'an station can be correlated with the activity of ground fissure and the increase in the activity of small earthquakes. It is a reflection of the change in stress-strain of this area.