【摘要】 汶川5.12大地震发生后,在武都汉王地震台及其附近地区布置了2个大地电磁测深点,进行了两期余震序列的地震电磁效应连续监测,共观测到M_s4.0及以上的余震事件35次.通过与汉王强震台的地震记录数据中15个强震记录比较发现,与地震波相对应的地震同震电磁信号存在于所有的电场和磁场记录分量中,它们与地震波到达同步.地震破裂发生时的电磁辐射信号在记录数据中相比地震波达到观测点的电磁信号幅度要小得多,无法从观测数据识别出来.通过分析对比地震位移和同震电磁信号的关系,提出了地震电磁同震信号产生的地震波驱动机理,认为观测系统在地球基本磁场中随地面运动产生了地震同震电磁信号,并从观测的地震振动位移和电磁信号进行了验证.更多还原

【Abstract】 The measurement of electromagnetic field at two sites in Hanwang and Chouziba for monitoring aftershock series has been done in continuous observation after the M_s8.0 Wenchuan earthquake on May 12, 2008.The measurement was done in two periods.Recorded data covered 35 aftershocks with magnitude more than M_s4.0.Comparing with the seismic data recorded at Hanwang station for 15 events, the coseismic signal of aftershocks exists on all components of the magnetic and electric fields at two different sites.The EM coseismic signals arrived simultaneously with the seismic waves, but not at the origin time of the earthquake.The signal produced at the origin time of the earthquake is much smaller than coseismic signal of the waves. It can t be identified from the time series.In addition, the generation of coseismic electromagnetic signals can be explained by earthquake dynamo mechanism.Analysing and comparing the relationship between the seismic displacement and EM coseismic signals, the mechanism of EM coseismic signal generation appear to be driven by seismic waves.That is, the EM observation system set up in geomagnetic field moved with the ground motion so that the EM coseismic signals were produced.The observations of seismic displacement and electromagnetic signals verified it.更多还原