STUDY ON THE SUBSURFACE FLUID ANOMALIES BEFORE WANGQING MS7.2 DEEP EARTHQUAKE

Before Wangqing Ms7.2 deep earthquake occurred on June 29 of 2002, a group of tendency and short-term precursory anomalies were observed by part wells of the subsurface fluid observing net in Jilin. The characteristics of these anomalies and its evolving process in time and space are presented here. The results show that the time that anomalies appear is relevant to distance of epicenter, and its distribution has migratory feature, which contracts from outside to inside with a low speed in medium term period, and exhales from epicenter to outside with a high speed in short term period. The blind zone of anomaly is epicenter region.