远场大震同震水位振荡、水温下降类型机理初步研究

On the mechanism of water temperature drop and water level oscillation in response to remote strong earthquakes

在2004年12月26日印尼苏门答腊M_s8．7级地震同震水位、水温变化类型的对比分类中,发现出相当具有规律性的一类变化类型：在某些观测井当水位出现振荡(水震波)的时候,同井水温绝大多数会有个几十分钟到数小时的从下降到恢复的过程。为此笔者又收集了其中的典型变化观测井,北京良乡井和河北唐山矿井2001年数字化以来30多次不同远场大震水位、水温的同震响应资料,发现无一例外都具有相同的规律性。在此基础上,笔者提出了对于同震水位振荡,温度下降的气体脱逸模式,并对气体脱逸的两种途径进行了动力学的分析。

During studying the characteristics of co-seismic and post-seismic water level and tem-perature changes in some wells of the subsurface fluid monitoring network of China,due to December 26,2004,Ms8.7 Sumatra Earthquake,we found a significant phenomenon:after the arrival of seismic waves,the water level oscillated,at the same time water tem-perature dropped quickly,and it took several tens of minutes to several hours for the wa-ter level and temperature to return to the pre-seismic level.We collected 30 far strong earthquakes data of two representative wells(LiangXiang well in Beijing City,Tang ShanKuang well in HeBai province).The same phenomenon was found in all cases.By comparing the hydrogeological and observational conditions of wells with water level oscil-lation but with or without water temperature change,we bring forth a mechanism to ex-plain this phenomenon:geogas escaping model.Finally,we analyzed the dynamic process of two ways for geogas escaping from water and rock.