Abstract: The paper studies the coseismic changes of water level and water temperature caused by the M_S 8.0 Wenchuan earthquake.The differences of water level and water temperature variations caused by the M_S 8.5 Sumatra earthquake on Sep.12,2007 and the M_S 8.0 Wenchuan earthquake on May 12,2008 are analyzed.The result shows that the well water level change caused by Wenchuan earthquake is dominated by rising.Spatial distribution of wells with water level rising or descending exhibits regional difference.The proportion of wells is higher with water level and water temperature changes in the same directions than in the reverse direction.Water temperature mainly dropped when water level fluctuated.Compared to remote earthquake,near earthquake caused bigger changes in water level and water temperature in wells.Coseismic changes of all the well water level and most of water temperature kept the same direction regardless of distance,magnitude,focal mechanism of earthquakes or epicentral directions,though water temperature direction changes occurred only at some peculiar wells.The water temperature direction changes were caused by changes of artesian condition and water level response from fluctuations to steps.The direction of water level changes might be controlled mainly by both local geological structures and hydro-geological conditions of the well.However,the direction of water temperature relates with mixing of water in the well,the location of the water temperature probe and other factors.The mechanisms of water temperature coseismic change are more complicated.

Key words: M_S 8.0 Wenchuan earthquake, coseismic change, water level, water temperature, M_S 8.5 Sumatra earthquake

摘要： 分析了汶川M_S 8.0地震在中国大陆引起的水位、水温同震变化特征,对比研究了2007年9月12日印尼苏门答腊M_S 8.5远震和汶川M_S 8.0近震在四川及其附近地区引起的水位、水温同震变化差异,结果表明:汶川地震在中国大陆引起的水位同震变化以上升为主,同时水位上升与下降的井点空间分布表现出一定的分区性;水位、水温同方向阶变的井点数比例高于两者反方向阶变井点数比例,当水位同震变化为振荡型时,水温以下降型为主;相对于远震,近震引起的水位、水温同震变化井点数量增加,无变化井点数量减少;所有井水位和大多数井水温同震阶变的方向都不因地震的远近、大小、震源机制或地震方位的变化而改变,个别发生水温同震升降方向变化的井点是由于水的自流状态和水位同震阶变由振荡转为阶变的改变所引起;水位同震升降性质受控于当地的地质构造环境和水文地质条件,而水温同震变化还与地震波引起的井孔中水的运动方式、水温探头放置的位置等因素有关,其机理更为复杂。

关键词: 汶川M_S 8.0地震, 同震变化, 水位, 水温, 印尼M_S 8.5地震