【摘要】 在晋、冀、蒙三省交界地区 ,1996年 12月出现了顺义震群、 1997年 11月出现了应县、凉城震群、 1997年 12月出现了浑源震群 ,这种现象可能预示着张北地震的到来。另外 ,这几次震群除应县震群外 ,b值均较低 ,可能是张北 6 2级地震在孕育过程中应力集中的反映。再者 ,在三省交界区 ,1997年ML3 0以上地震活动水平较 1996年明显增强 ,b值出现了明显下降 ,可能是张北 6 2级地震应力集中造成微破裂加剧的结果。而张家口ML4 5级地震可能是张北地震的显著地震。通过对这几次震群及 1996、 1997年发生在N39°30′～ 42°0 0′ ,E113°30′～ 116°10′范围内地震的活动性分析 ,笔者认为没有能有效地对张北 6 2级地震做出预报是遗憾的。在对地震进行测震学指标分析 ,b值对应张北地震活动性较好 ,而Q值、Vp/Vs指标对应张北地震不明显。更多还原

【Abstract】 The Shunyi earthquake swarm, the Yingxian and the Liangcheng earthquake swarms, and the Hunyuan earthquake swarm occurred in the place where Shanxi, Hebei Provinces and Inner Mongolia Autonomous Region meet and respectively in December 1996, November 1997 and December1997, which might mean the coming Zhangbei earthquake. And also, these earthquake swarms except the Yingxian earthquake swarm had low b values, which probably reflected stress concentration in the seismogenic process of the Ms 6 2 Zhangbei earthquake; besides, in the meeting place, seismicity with M L3 0 or more in 1997 was stronger than that in 1996 and the b value came down clearly and perhaps it was a results of microfracture intensification caused by the stress concentration for the Zhangbei earthquake, and the M L 4 5 Zhangjiakou earthquake maybe was a signal earthquake of the Zhangbei earthquake. Through analyzing these earthquake swarms and the earthquakes occurred in N 39°30′ - 42°00′ and E 113°30′ - 116°10′ in 1996 and 1997, the authors think it is a pity that the Zhangbei earthquake was not predicted effectively. It is found in analyzing the indexes of seismicity that b value was in good correspondence with the Zhangbei earthquake, but no obvious correspondence with the Zhangbei earthquake for Q value and Vp/Vs.更多还原