【摘要】 在对 1 995年山东省苍山 5 2级地震异常筛选的基础上 ,分析了异常群体阶段性演化过程。结果表明 ,震前 1 0a左右震中周围出现小震小区域综合断层面解主压应力P轴偏转 (约 3 0°) ,震前 7a左右震中附近 3～ 4级地震增强集中及应变释放加速 ;震前 4a左右转为异常平静 ;震前 1a左右震中外围开始出现形变类前兆异常 ,前兆异常台站比和异常台项比约达 6%及 4%左右 ,异常比例偏少 ;震前约半年起 ,以震中附近地震波速比异常出现为起点 ,相继出现各类前兆异常 6条 ,短期前兆异常台站比和异常台项比分别约达 2 5 %和 1 7%左右 ,显示孕震进入短期阶段 ,但临震异常不明显。对由此获得的 5级地震预测启示进行了讨论。更多还原

【Abstract】 The evolution processes of different stages for the Changshan Ms5 2 earthquake in 1995 of selected anomal swarms are analyzed.The result shows that around the epicentre,10a prior to the earthquake,the principal compressional stress orientation P of minor regional fault plane solutions for minor earthquakes deflected about 30°;7a prior to the main earthquake,earthquakes magnitude 3 0～4 0 got concentrated and strain released rapidly;4a,quiet abnormally;1a,the deformation precursory anornalies arose,ration precursory anornalies arose,ratio of precursory anomaly stations and items reached to 6% and 4%,the ratioes of anomalies were less;Half a year and from then on,anomaly of seismic wave velocity ratio rear the epicentre arose and 6 precarsory anomalies of every kinds arose,ration of precursory anomely stations and items of short term reached to 25% and 17% or so,showed that the seismogenic process had come to stage of short term,but the close seismic anomaly was still not oboious.更多还原