【摘要】 将1966年以来中国大陆发生的75次6.5级以上地震分为52组,按华北-东北、西南、青藏块体、新疆不同构造区域,分别对其6.5级以上强震前4级、5级以上地震活动图像进行了全时空扫描,选取震前特征图像,按构造区域进行分析、总结,研究强震前中等地震活动图像演变的基本特征,及其震前图像演化的共性和差异性。研究结果表明:强震前不同级别中等地震活动出现二个阶段异常图像转化具有普适性。5级地震图像后期在时间和空间上配套出现的4级地震的异常图像,可能是强震孕育过程中由中期向短期过渡的一种标志。更多还原

【Abstract】 75 earthquakes with M≥6.5 happened in China’s mainland since 1966 are divided into 52 groups.Based on the spatio-temporal scaning of their seismicity patterns with M≥4 and M≥5 respectively,we chose typical patterns and analyzed their characteristics of evolution,consistency and difference according to North China-Northeast China,Southwest China and Xinjiang tectonic regions.It comes to a conclusion that the anomalous pattern transition of two stage happened before strong earthquakes is a common phenomenon.The anomalous patterns with M≥4 after the seismicity patterns with M≥5 may be a sign of transition from the medium term to the short term during preparation of strong earthquakes.更多还原