2008年中国大陆6.0级以上地震前后电磁脉冲异常现象  

ELECTROMAGNETIC ANOMALOUS PULSES BEFORE AND AFTER EARTHQUAKES(M>6.0) IN CHINA CONTINENT IN 2008

作　　者：高曙德[1] 赵国泽[2] 汤吉[2] 苏永刚[1] 詹艳[2] 王立凤[2] 

机构地区：[1]中国地震局兰州地震研究所,兰州730000 [2]中国地震局地质研究所,北京100029

出　　处：《地震地质》2016年第4期987-1004,共18页Seismology and Geology

基　　金：国家自然科学基金(41174059;41074047;41374077)资助

摘　　要：分析了2008年中国大陆新疆乌鲁木齐和云南通海2个地震台站观测的电磁场资料,研究了这些资料显示的异常现象和2008年发生在中国大陆的汶川地震等5次6级以上地震之间的对应关系,为利用电磁法进行地震监测研究提供了新的震例。分析结果显示,频率范围为800~0.1Hz的电磁场的自功率谱密度（PSD）随时间的变化与地震事件之间存在如下关系：1）电磁场的自功率谱密度在地震之前出现了明显的脉冲异常,如汶川MS8.0地震前磁场的脉冲异常值比背景场大约2个量级;2）异常幅度随着离开震中距离的增大而减小;3）磁场自功率谱密度异常的幅度,与台站相对于震中的方位以及电磁场的频率有关;4）脉动异常具有时间上的集丛现象。In this paper,we provided the electromagnetic anomaly phenomena prior to five earthquakes with magnitude MW 6. 0 occurring in China continent in 2008. The electromagnetic data in frequency bands 800 ~ 0. 1Hz are recorded at two stations located in Urumqi,Xinjiang Uygur Autonomous Region（ URQ） and Tonghai,Yunnan Province（ TH）. The time series of four horizontal components of the electromagnetic field at the stations are converted to the spectra using Fast Fourier Transform. The relationship between the electromagnetic anomalous phenomena and the earthquake events is studied through analyzing the temporal variation of electromagnetic spectra and comparing them with earthquake events. This study provides the new examples for electromagnetic anomaly phenomena before the earthquakes. The following features can be found. 1The obvious anomalous power spectrum density（ PSD） of electromagnetic fields in frequency band of 128 ~ 0. 5Hz appeared before earthquakes. The anomalous PSD is related to the earthquake magnitude and the epicenter distance.The anomaly size of magnetic PSD is about 1-3 orders of magnitude bigger than the background field before Wenchuan MS8. 0 earthquake. 2 The changes of parameters are also related with frequency of the signal; The ELF signal strength observed at seismic stations is significantly related with distance between the stations or the measured magnetic and electrical field components and the source of earthquake. We also found that the field strength attenuated faster in area closer to the source than in far area. It is clear that the magnetic signals have higher signal noise ratio than the electric data. 3The amplitudes are also related with the azimuth of the earthquake to station and with the frequency of the data. 4 The anomalous pulses showed cluster phenomenon in time.

关 键 词：电磁异常脉冲 地震监测 电磁场频谱 脉冲集丛 

分 类 号：P315.72[天文地球—地震学]