The Anomaly Field of Subsurface Fluids and Its Formation and Evolution Mechanism Before Three Strong Earthquakes in the Northern North China Area

摘要

The data of pre-seismic subsurface fluid anomalies of such earthquakes as Datong-Yanggao M_s 6.1 event on Oct. 19, 1989, western Baotou M_s 6.4 event on May 3, 1996 and Zhangbei- Shangyi M_s 6.2 event on Jan. 10, 1998 are systematically collected and arranged. Then the Features of patterns, spatial distribution, time variation and time-spatial evolution of these Anomalies are compared and comprehensively analyzed. Then the formation and evolution Mechanism of medium- and short-term anomaly field of subsurface fluids in the northern North China area is proposed.