川滇地区单断裂强震区与多断裂强震区

Single-Fault Strong Earthquake Regions and Multi-Faults Strong Earthquake Regions in the Sichuan-Yunnan Region

以《全国小震目录》(196 5年 1月 1日～ 2 0 0 2年 10月 31日 )和《四川地震台网快报目录》(2 0 0 2年 11月 1日～ 2 0 0 3年 9月 30日 )为基础资料 ,研究了川滇地区地震活动性发展变化的主要特征 ,并提出“单断裂强震区”和“多断裂强震区”概念。发现川滇地区主要单断裂强震区在发生一些强震之后 ,已经陆续进入地震平静时段 ,近期发生强震的能力明显减弱。与此同时 ,“滇西南”、“龙陵 -腾冲”、“丽江 -武定”地区分别在较短时段内发生多次强震 ,表明这几个多断裂强震区陆续进入活跃时段 ,成为 1984年以来川滇地区的地震主体活动区域。多断裂强震区具有区内中小断裂汇集、地质构造复杂、地震活跃时段多次出现、在同一活跃时段内又具有活跃小段与小段间距的小段组合形式等特征。对已有的和可能新生的多断裂强震区进行早期判定 ,以及对活跃时段、小段组合进行动态跟踪 ,对于川滇地区地震预报具有重要意义。

The main characters of the developments and changes of the seimicity in the Sichuan-Yunnan region are studied, and the concepts of “single-fault strong earthquake region' and “multi-faults strong earthquake region' are reported, with “Catalogue of Chinese Earthquakes' (1965-01-01～2002-10-31) and “Catalogue of Sichuan Earthquake Station Network (fast report)' (2002-11-01～2003-09-30). It is discovered that the single fault strong earthquake regions in the Sichuan-Yunnan region have entered the strong earthquake calm time interval successively, and the strong earthquake occurreue ability has greatly weakened after the several strong earthquakes in these regions. At the same time, the several strong earthquakes occurred in the “Southwestern Yunnan region', “Longling-Tengchong region', “Lijiang-Wuding region' separately in the shorter time interval, it is found that the “Southwestern Yunnan region', “Longling-Tengchong region' and “Lijiang-Wuding region' had successively entered the strong earthquake active time interval and became the main earthquake active region in the Sichuan-Yunnan region since 1984. There are many middle and small faults, complex geologic structure, several earthquake active time intervals, and the composition of the active segments and the calm segments in a same active time interval in these multi faultsstrong earthquake regions. The early judge on the present and the occurring multi faultsstrong earthquake regions and the careful track on the active time intervals and the composition of the segments have the important significance for the forecast of earthquakes in the Sichuan-Yunnan region.