唐山地震对北京地区地磁场总强度的影响
THE EFFECT OF THE TANGSHAN EARTHQUAKE ON THE GEOMAGNETIC TOTAL FIELD IN THE PEKING AREA
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摘要: 1976年7月28日, 唐山7.8级地震的震中西侧约200×140公里地区内的2×108个测点上(图1), 自1975年2月开始用质子旋进磁力仪每月进行一次地磁场总强度的观测.对全部测点观测资料的分析后发现, 全测区磁场的异常变化较小.测点密度较大以及震前震后长时间多次重复观测的资料积累, 使我们有可能进一步从时间和空间上进行统计分析, 以便更有效地排除干扰.1975年2月至1977年2月, 全部测点共25次重复资料的统计结果表明:地磁统计量与唐山地震在时间和空间上有一定的相关性, 为震磁关系的研究提供了有意义的结果.Abstract: In the area west (about 140×200 km) of the epicenter of the Tangshan earthquake of magnitude 7.8, repeated measurements of the geomagnetic total field, once each month, have been made since February 1975, using the proton precession magnetometers, at 108 pairs of points (Fig. 1). In analysing the data thus obtained, it is found that anomalous variations of the geomagnetic total field within the entire area are relatively slight. Higher density in the distribution of surveyed sites and more repetitions of measurements during a relatively longer period of time before and after the earthquake, make it possible to do statistical analysis with regard to time and space, so as to eliminate disturbances from all kinds of sources more effectively. From February 1975 to February 1977, the statistical results of 25 repeated measurements made at all the sites show that there exists certain correlation between the geomagnetic statistical parameters and the Tangshan earthquake, both in time and space, thus providing interesting results for the study of seismo-magnetic effect.
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