震前大气电场异常的区域性特征

REGIONAL FEATURES OF ATMOSPHERIC- ELECTRIC FIELD ANOMALIES BEFORE EARTHQUAKES

在验证了近场每次较大地震发生前,均能观测到明显的大气电场负异常信息。在观测不到明显的大气电场负异常时,近场近期一般不会有较大地震发生的基础上,本文以北京及其附近地区为例,利用所观测到的大气电场异常资料及1985年后该地区所发生的8次M_L≥4地震资料,较深入地探讨了震前大气电场异常的空间分布特征,取得了一些规律性的认识: (1)异常多发生在距震中不太远的范围内,且随着震级的增大异常区的范围也增大。 (2)较大地震发生前,距震中近的台站比远的台站记录到的异常次数要多。 (3)较大地震发生前,近场一般会有两个或两个以上台站同时记录到明显的大气电场负异常信息。 并通过预报实例阐述了它在近场地震短临预报中的应用和意义。

According to the obvious negative anomaly information of the atmospheric electric field recorded before occurrence of each near-field larger earthquakes, taking Beijing and its vinicity as an example, this paper disccussed the space distribution features of atmospheric-electric anomalies before earthquakes using the abnormal data of the observed atmospheric-electric field and the seismic data of 8 earthquakes with M > 4 occurred in this region since 1985. Authors obtained a few regularity knowledge: 1. Most anomalies occurred in the range not far from the epicenter and the range of the abnormal region also increases with increase of the magnitude. 2. The stations, closer to the epicenter can record more anomalies than those stations far from the epicenter before larger earthquakes. 3. Generally two or more stations in the near field can record obvious negative anomaly iniormation of the atmospheric electric field simultaneously. Authors here also explained its action and the meaning in the short-term and impending earthquake prediction through some predicted examples.