基于极值特征尺度的干扰辨识技术在地磁观测中的应用研究

在地震前兆观测台网中,地磁和地电同台观测是较为常见的,地电测量时的供电干扰会引起同台地磁观测数据的变化,造成地磁观测精度下降.本文在分析产生地电供电干扰的机理及特点基础上,提出了采用噪声辅助的基于极值特征尺度的干扰辨识,对采用线性差值辨识出的干扰区间利用这种技术进行填充.并将该方法应用到成都、洛阳、徐庄子和蒙城四个磁电同台观测数据的分析处理中.结果表明:该方法在地电供电对地磁资料的干扰辨识精确度方面和干扰抑制损失上有较好的效果和较高的稳定性,辨识精确高,抑制损失相对与传统滤波器达到最小程度.在抑制地电供电干扰,提高地磁观测精度方面有较好的应用价值.

A method for geoelectric counts interference reduction based on extrema ccharacteristic scale

Geomagnetic and geoelectric measurements is carried out at the same time in some stations of the earthquake precursor observation networks of China.Due to this situation,the geomagnetic signals can be interfaced by the geoelectric measurement once an hour.This will make earthquake precursor and other anomalous geophysical information difficult to be distinguished from geomagnetic signals,meanwhile,the observation data quality will declined.The paper firstly analyzes the characteristics and mechanism of this kind of interface,then extrema characteristic scale as well as pre-whitening technology is introduced as the effective methods to geoelectric counts interference identification and reduction.Normal distributed white noise as an assistive technology is added into original geomagnetic data in order to help identify the interface intervals with extrema scale precisely.Then these identified intervals are filled with linear interpolation.Using this method thought stimulated geomagnetic diurnal change data,the max reduction loss is ±0.03nT.This method was applied to data of observation stations of Chengdu(CDP),Mengcheng(MCH),Luoyang(LYA)and Xu Zhuangzi(XZZ).The result shows that this method has a high and stable identification accuracy and minimal reduction error.It’s a valuable method in geoelectric counts interference reduction and geomagnetic data accuracy improvement.