国内外有许多震例说明,大震前区域地震活动有明显的增强过程。梅世蓉1960年研究表明,我国历史大震,如1668年郯城大震和1679年三河—平谷大震前,有感地震频度增加后又减弱。文献[2]、[3]认为震前活动性增强范围比主震震源区大得多。近年来这方面 Many earthquake examples at home and abroad show that the seismic activity in the area before the earthquake greatly enhanced. The study of Mei Shirong in 1960 showed that before the earthquake of great magnitude in our country, such as the Great Wallquake in Gaocheng in 1668 and the Great Three-River-Pinggu Great Wave in 1679, the magnitude of earthquakes increased and then weakened. Literature [2], [3] think that the scope of the enhanced activity before the earthquake is much larger than the mainshock source area. In recent years in this area