Abstract: The observation of water temperature in deep well has been carried out for more than 20 years in China.However,the study on the mechanism of water temperature co-seismic response is inadequate at present.On December 26,2004,the great earthquake of M_S 8.7 occurred in the northwest offshore of Sumatra,Indonesia.After the shock,most of the observation wells in China recorded the coseismic response of water level and temperature.We studied the co-seismic response characteristics of water level and temperature in 121 wells and found the regular response characteristics.When the water level in a well oscillates,its water temperature will drop at the same time.The process will continue from dozens of minutes to several hours,and the process of the water temperature drop corresponds to the process of the water level oscillation.Once the water level oscillation stops,it restores to the level before the earthquake immediately.But,the water temperature rises at a slow speed and will take several hours to attain its former level.

Key words: water level oscillation, water temperature drop, co-seismic response, gas escape

摘要： 深井水温观测在中国已经开展了20年,但目前对于水温响应机理的研究还不充分。在对2004年12月26日印尼苏门答腊M_S 8.7地震后,中国地下流体观测井网中121个观测井水位、水温同震响应特征的研究中,作者发现了具有规律性的一类变化类型:当某些观测井水位出现振荡的时候,其同井水温绝大多数会出现几十分钟到数小时的下降—恢复过程。为了对此现象进行验证,又收集了河北唐山矿井2001年数字化以来39次远场大震水位、水温的同震响应资料,发现其具有相同的规律。在对可能造成水温下降的影响因素研究分析的基础上,提出了同震水温下降的气体脱逸模式,给出了在气泡脱逸过程中造成水温下降的2种主要影响因素,并利用此模式对部分观测现象进行了较合理的解释。

关键词: 水位振荡, 水温下降, 同震响应, 气体脱逸