汶川8.0级地震与苏门签腊8.7级地震井水温度同震响应特征分析

Analysis of the Characteristics of Coseismic Changes of Water Temperature Caused by Wenchuan M8.0 Earthquake and Sumatra M8.7 Earthquake

基于中国大陆地下流体台网井水温度数字化观测数据,本文对比分析了2008年5月12日汶川8.0级地震与2004年12月26日印度尼西亚苏门答腊8.7级地震引起的水温同震响应特征。结果表明,地震能引起井水温度发生同震响应,而井水温度同震响应特征可能主要与井孔本身的水文地质条件和区域构造环境有关。同时,根据水位同震响应资料和前人的研究结果,本文对水温同震响应的机理进行了探讨,认为在地震波动力加载作用下,井-含水层系统原有状态发生改变,很多因素可以引起井水温度发生变化,例如井孔垂直方向上因对流和水动力弥散引起的温度变化、井-含水层系统水平方向上水流状态改变引起的温度变化、井孔水由于气泡脱逸引起的温度变化、井孔水与井壁及水温探头摩擦引起的温度变化等,因而,合理考虑以上因素,才能有效分析井水温度同震响应的机理。

Based on the well water temperature data of the underground fluid observation network in mainland of China,the authors analyze the characteristics of coseismic changes of water temperature caused by Wenchuan M8.0 earthquake and Sumatra M8.7 earthquake.The results show that earthquakes can cause changes of well water temperature,and the characteristics of the changes may be mainly related with the wells’hydro-geological conditions,local geological structures and tectonic environments.Meanwhile,based on the results of previous and present studies,the authors analyze the mechanisms of coseismic changes of water temperature.It is considered that under the dynamic loading of seismic wave,the original state of the well-aquifer system is changed,and a number of factors can cause well water temperature to change,including convection and hydrodynamic dispersion in the vertical direction of the wells,flow state changes in the horizontal direction of the well-system,gas escape from the well water and frictions between the well water,temperature probe and well inner surface and so on.Therefore,in order to effectively analyze the mechanisms of coseismic changes of water temperature,it is reasonable to consider all these factors.