南北地震带地磁加卸载响应比应用研究

发布时间：2018-05-30 13:34

本文选题：地磁加卸载响应比 + 日变幅　；参考：《地质科技情报》2017年04期

【摘要】：强震前孕震体环境由于应力变化引起介质电导率等电磁性质的改变,区域地磁场垂直分量日变曲线会出现相位和幅度变化,地磁加卸载响应比是识别幅度异常的有效方法。计算了南北地震带及邻区18个显著地震事件前震中周边地磁台站垂直分量加卸载响应比,分析了地震前后地磁加卸载响应比时空分布特征及产生机理。研究结果显示:(1)在排除空间天气、台站周边观测环境、仪器及监测系统等因素的前提条件下,部分中强地震前,地磁加卸载响应比出现异常,占比44.4%。(2)地磁加卸载响应比阈值受纬度影响,同经度条件下,纬度越大、阈值越小;经过反复调试与对比,计算结果显示南北地震带北段响应比阈值为3.0、南段及西南地区为3.1。(3)一般情况下,异常出现后6个月内,发生中强以上地震,异常台站数量越多,对应的地震震级越大;中强地震震中位于阈值线附近可能性较大。
[Abstract]:The phase and amplitude of the daily variation curve of the vertical component of the geomagnetic field will appear due to the change of electromagnetic properties such as the conductivity of the medium caused by the change of stress in the seismogenic body before the strong earthquake. The response ratio of geomagnetic loading and unloading is an effective method to identify the amplitude anomaly. The loading and unloading response ratio of vertical component of the geomagnetic station around the epicenter before the earthquake event is calculated and the spatial and temporal distribution characteristics and generation mechanism of the geomagnetic loading and unloading response ratio before and after the earthquake are analyzed. The results show that the geomagnetic loading / unloading response ratio is abnormal before some moderate strong earthquakes under the precondition of excluding the space weather, the observation environment around the stations, the instrument and the monitoring system, etc. The threshold value of the geomagnetic loading and unloading response ratio is affected by latitude. Under the same longitude condition, the greater the latitude, the smaller the threshold value; after repeated debugging and comparison, The results show that the response ratio threshold of the northern segment of the north-south seismic belt is 3.0, and that of the southern segment and southwest region is 3.1.In general cases, within 6 months after the occurrence of the anomaly, the more moderate earthquakes occur, the more the number of anomalous stations is, and the larger the corresponding magnitude is; It is possible that the epicenter of the moderate earthquake lies near the threshold line.
【作者单位】：中国地震局地震研究所地震大地测量重点实验室;湖北省地震局;江苏省地震局;
【基金】：中国地震局地震监测、预测、科研三结合课题(161704);中国地震局震情跟踪专项工作任务(2016010411)
【分类号】：P315.721

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