【摘要】 选取晋北区展布的一组NE向断裂作为背景场,使用1970年以来较完整的地震资料,统计分析了(1970年1月1日~1998年12月31日)晋北区中小地震(3.0≤ML≤5.0)沿该组断裂的活动特征等,发现在1976年内蒙和林格尔6.5、1989年山西大同-阳高6.1、1996年内蒙包头6.4和1998年河北张北6.2级中强地震前1~2年内,晋北地区的中小地震活动年频次及强度有明显的衰减—显著增强—发震这一特征,这种相关特征对预测晋冀蒙交界地区未来中强震的时间具有参考价值;震前主震近场区的地震条带活动对主震位置有预示意义,而较远场的地震活动仅反映主震前应力水平的增强,并有震前活动向未来强震区靠近的特征,这对预报主震的方位有一定意义。更多还原

【Abstract】 By taking a group of faults with NE trend, laying out on the Northern Shanxi, as a background and using the rather complete seismic data since 1970, the feature of seismic activities(from Jan 1, 1970 to Dec 31, 1998) of medium and smaller earthquakes (3.0≤ M≤5.0 ) along the faults is analyzed statistically. It is found that in 1 to 2 years before the 1976 Helingeer, Inner Mongolia, earthquake of M 6.5, 1989 Datong-Yanggao, Shanxi, earthquake of M 6.1 , 1996 Baotou, Inner Mongolia, earthquake of M 6.4 and 1998 Zhangbei, Hebei, earthquake of M 6.2, the yearly frequency and intensity of seismic activities of medium and smaller earthquakes in Northern Shanxi all show the features that come through attenuating, increasing strikingly and finally, earthquake occurring. These correlations are valuable for predicting occurring time of medium-strong earthquakes in the juncture area of Shanxi, Hebei and Inner Mongolia. On the other hand, zonary seismic activity in area around main shock before an earthquake would be meaningful for forecasting the location of the main shock. Meanwhile, seismic activity in area far from a main shock, which usually moves towards area where a strong earthquake will occur, may indicate increase of the stress before main shock, being helpful for predicting azimuth of the main shock.更多还原