共和7.0级地震前地下流体前兆的动态演化特征
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摘要
使用４０个地下流体观测点的资料，对１９９０年４月２６日青海省共和ＭＳ７．０地震的前兆动态特征进行了系统研究．结果表明：（１）地震带内观测点的水氡趋势异常及水化、水位群体异常及频次异常与断层平均形变速率呈同步变化．地下流体群体异常频次的累加值曲线在地震前表现为指数加速变化图形．（２）震源外围２４０ｋｍ范围内的水氡中短期趋势上升异常，表现为由震源逐渐向外围扩散的特点．在短临阶段各测点水氡的异常变化基本同步．（３）流体短临前兆出现明显的起伏加剧和层次现象，突出的表现是流量、断层气日变化在临震阶段出现３次加剧，且异常幅度一次高于一次
The dynamic evolution characteristics of ground fluid precursors of the M S7.0 Gonghe earthquake on April 26,1990 in Qinghai Province are systematically studied, by using the ground fluid data of 40 observation stations. The results are following: (1) The mean deformation rate of faults in seismic belt were synchronous with the cluster anomaly frequency of the ground fluid and the trend anomalies of radon content in groundwater. The curves of the deformation rate of fault and the accumulative frequency of the ground fluid cluster anomalies changed acceleratly in a law of index. (2) The acceleration and rising stage of medium term tendency anomalies of the radon data, which were obtained from the observation stations within 240 kilometers of the focus of the M S7.0 Gonghe earthquake showed transmission feature from the focus to the periphery. The anomalies in short impending term of the radon data appeared synchronously. (3) The ground fluid precursors showed clearly aggravation of fluctuation and hierarchy pattern. It is obvious that the change of daily mean values of fault product gases and flow of groundwater showed three hierarchies with anomalous amplitude which are higher and higher each in the impending earthquake stage.
The dynamic evolution characteristics of ground fluid precursors of the M S7.0 Gonghe earthquake on April 26,1990 in Qinghai Province are systematically studied, by using the ground fluid data of 40 observation stations. The results are following: (1) The mean deformation rate of faults in seismic belt were synchronous with the cluster anomaly frequency of the ground fluid and the trend anomalies of radon content in groundwater. The curves of the deformation rate of fault and the accumulative frequency of the ground fluid cluster anomalies changed acceleratly in a law of index. (2) The acceleration and rising stage of medium term tendency anomalies of the radon data, which were obtained from the observation stations within 240 kilometers of the focus of the M S7.0 Gonghe earthquake showed transmission feature from the focus to the periphery. The anomalies in short impending term of the radon data appeared synchronously. (3) The ground fluid precursors showed clearly aggravation of fluctuation and hierarchy pattern. It is obvious that the change of daily mean values of fault product gases and flow of groundwater showed three hierarchies with anomalous amplitude which are higher and higher each in the impending earthquake stage.
引文
1陈培善．地震目录．地震学报，1991，13（1）：125～128．2王吉易，郑云贞，张素欣，等．水化多层次加速前兆图象．中国地震，1994，10（增刊）：157～165．3秦保燕，李佐唐．共和地震前兆起伏加剧的层次性与大震的跟踪预报．西北地震学报，1995，17（3）：1～9．4李宣瑚．水氡异常的扩散收缩现象．地震，1981，（5）：41～43．5何跟巧，常秋君，郭玉英．茫崖、共和地震与断层气动态异常．内陆地震，1990，4（4）：367～373．6张新基，王长岭，张慧．西北地区水化特征及地震预测研究．地震，1994，（增刊）：1～6．
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