THE CHARACTERISTICS OF PRECURSORY ANOMALY FOR EARTHQUAKE GROUP

Based on two earthquake groups occurred in North China, the characteristic of precursory anomaly for earthquake group is analyzed. The characteristics of anomaly for earthquake group mainly are: (1) the temporal span of anomaly is large, and the anomaly, which behaves tendency anomaly, generally run through the whole earthquake group; (2) there are small fluctuations under the tendency background of the anomalies for earthquake group, which is new response for a single earthquake; (3) the figures that exists anomaly of earthquake group generally have large turning or kick before the beginning of a group; (4) there is usually correlativity between the anomalies of different approaches.