区域性地震过程对中国大陆洪水影响之初探

Influence of Regional Earthquake on Flood in China's Mainland

为探讨地震、洪水(暴雨)间可能存在的链状关系,以1979—1990年为例,对中国及周围区域M≥7地震的活动格局与中国大陆洪涝灾害的时空分布特征进行了分析研究。结果发现:类似于2005年西江洪水,不少大洪水(暴雨)也位于地震迁移线上或其附近。洪涝的发生时间有可能与震链的后震或前震比较接近,或与震链推移之进程基本吻合,反映了链程中的场态效应。震链之进程往往构成三角之类的几何体或兼具振荡特征,所围限区域在气象条件允许时,有可能发生强降雨;中国大陆若完全在"几何体",可能当年洪涝灾害相对较弱。洪涝(暴雨)并非都与地震有关。某些震链"几何体"对降雨的影响可能与季风有关。强震对降雨往往有时空近程影响。震群或震链多线程指向点、端点、交会点、角夹持地带可能加剧洪涝。震链回迁或转折处往往是不同体系、单元、性质构造的复合点,震源应力变异点,形态与活动方式复杂。

To research the catenulate relationship between earthquake and flood, the activity pattern of the M ≥7.0 earthquake and the spatio-temporal distribution of the flood in China's Mainland are analyzed. The results are as follows： similar to the Xijiang flood in 2005, most of the floods locate on or near the transfer tracks of earthquake. The flood usually happens shortly before or after the earthquake, or accords with the foreshock and after＇shock. Earthquake chain often has geometrical form such as triangle or oscillation form. If the meteorological condition is suitable, there may be precipitation in the form. The flood would be weak if China's Mainland is entirely in the polygon. Not all the floods concern with earthquake, some are related with monsoon. Strong earthquake often has short-range influence on precipitation. The flood is possibly getting intensified in the areas where the earthquake swarms or the chain multithreading directs spot, vertex spot, the crossover point and the angle region. The turn-about or transition of the earthquake chain always is the compound spot for different systems, units, structures or the aberrance point of epicenter stress field, and has complex forms and active way.