Abstract:

Rongchang area had exhibited low levels of natural seismicity,and there was no record of earthquake with M_L>5 in the history.However,following the injection of unwanted water from gas production,seismicity has increased dramatically and showed progressive increase of magnitude since July 1988,and an earthquake of M5.2 occurred in 1997.Rongchang area is thus an ideal site for studying seismicity induced by deep well injection.Unfortunately,there was only one seismic station in the area,and the research was limited by the poor detectability and hypocenter location accuracy.In order to make a thorough investigation on the injection-induced seismicity in the area,a temporal seismic network was installed in July,2008 under the cooperation of the State Key Laboratory of Earthquake Dynamics,Geological Survey of Japan and Chongqing Earthquake Administration.The seismic network consists of 6 stations,by which waveforms are continuously recorded.As a result,both the detectability and location accuracy are improved greatly.This paper presents a brief summary of the cooperative project and some preliminary results of recent seismicity in the area.

Key words: deep-well injection, induced seismicity, earthquake observation, Chongqing Rongchang

摘要：

荣昌地区地震活动性原本很弱,历史上无5级以上地震的记载。但自20世纪80年代末期开始,随着工业部门将采集天然气过程产生的污水通过废井回灌,该区地震活动明显增强,震级逐渐增大,并于1997年发生了5.2级地震,从而为研究注水诱发地震提供了理想的场所。由于该地区仅有一个地震台,监测能力和定位精度很低,难以满足研究工作的需求。地震动力学国家重点实验室会同日本地质调查所和重庆市地震局于2008年7月在荣昌地区架设了6套流动台站,对该区地震活动进行连续观测。在提高监测能力的同时,使地震震源的定位能力得到了明显的提高,为深入研究地震时空分布特征及注水诱发地震的机制提供了基础。

关键词: 深井注水, 诱发地震, 地震观测, 重庆荣昌