利用FFT方法对江苏区域地电场、地磁以及有关台站的钻孔应变数据进行处理,提取频谱特征,对该区各地电台站的地电暴特征进行分析,研究结果表明:①江苏区域地电场各测项地电暴数据与地磁H分量变化趋势接近,但各台地电场不同测项的突跳方向存在各向异性,4个地电台站EW向数据具有一致同向现象,NS向数据有差异性;②由各分量优势周期对应性可知,江苏地区地电场NS向含有的地磁场H分量高于体应变成分,地电场EW向倾向于地磁场H分量与体应变叠加抵消的结果;③当磁暴发生时,地磁H分量变化幅度相同的台站,地电场变化幅度不同,地电台站的地电暴变化特征与其地下结构有关,地下深层阻抗越大,感应电场越大,地电场日变化幅度越大。
The FFT method is used to process the geoelectric field data, the geomagnetic data and borehole strain data of some stations in Jiangsu region in this paper. Frequency characteristics are extracted, the formation and variation mechanism of geoelectric storm is described, and the geoelectric storm difference characteristic of Jiangsu ground geoelectric network is analyzed. The results of the study show that:① The variation tendency of geoelectric storm changes in different direction is very close to the geomagnetic H component, but the jump in different direction of the electric field platform has anisotropy. They are same to the phenomenon of the data in east and west direction in four geoelectric stations, but the data in north and south is not different. When the storm occurs, the rangeability of the electric field is different of these four stations while they have the same rangeability of magnetic storm. ②In terms of the correspondence of each component advantage period, the NS component of geoelectric field contains more component of geomagnetic H component than that of body strain components, while the EW component tends to the superposition and offset results of geomagnetic H component H component and strain, which is related to the pole arrangement of the electric field's NS and EW direction.③The variation characteristic of geoelectric storm has great relationship with geoelectric station's underground structure in Jiangsu area, namely the impedance of ground resistivity is greater, the greater the induced electric field, the greater the amplitude of the electric field's diurnal variations.
2018,39(5): 55-61 收稿日期:2018-04-23
DOI:10.3969/j.issn.1003-3246.2018.05.008
基金项目:中国地震局监测、预测、科研三结合课题(项目编号:171102);江苏省地震局青年基金(项目编号:201603)
作者简介:鲍海英(1986-),女,硕士,工程师,主要从事地震监测预报工作。E-mail:bhy5928@163.com
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