摘要
本文分析了华北北部地区(北纬37°—41°,东经114°—121°)1965—1986年地震目录,检测出爆发性地震10次。其中6次发生在邢台强震的余震区。研究了那些发生在非邢台余震区的爆发型地震与强震(M_s≥6.0)关系,并进行了“后验”预报。结果表明1965—1986年上述地区共发生M_s≥6.0地震5次,其中4次M_s≥6.5地震前1.5年内有爆发性地震出现。用随机二项式估算了爆发型地震与强震发生随机相遇的概率p,p=0.2％。用许氏R值评分方法估计了爆发型地震预报强震(M_s≥6.0)的效能为0.66。分析这4次爆发型地震所在区域可以看出:它们都发生在地壳破碎应力容易集中地区,这些地区可能是区域应力场增强时的灵敏点。因此,我们认为爆发型地震是区域应力场活动的标志之一,可能对强震发生具有预报意义。 按照本文论述的方法,分析了1987—1988年6月全国地震目录表明,上述华北北部地区在此期间,仅在1976年唐山强震的余震区内发生了2次爆发型地震。因此,预计1989年该地区可能不会发生M_s≥6.5地震。
Ten earthquakes of burst type are detected by analyzing the earthquake catalogue of the-north part of Huabei area (37°-41°N, 114°-121°E), from 1965-1986. Six of them occurred in the aftershock area of the 1966 Xingtai strong shocks. The relationship between the other four burst events and strong shocks with Ms 6.0 has been studied and post-tested for strong shock prediction. Results show that there occurred five strong earthquakes with Ms 6.0 in above area form 1965-1986, and that a burst event occurred within one and a half year before one of the four strong earthquakes (Ms 6.5) occuring. The random probability, p, of coincidence of burst events with strong shocks is 0.2% as estimated by random binomial. The efficiency of using burst.event to predict strong shocks (M>6) is 0.66 as estimated by Xu's R-value mark method. It can be seen by analyzing the regions where the four burst events located that all the burst events occurred in areas where the crust had been fractured and beneficial to stress concentration. These areas are probably sensative to regional stress increasing . Thus, we propose that the burst earthquake may be one of the signals reflecting regional stress activities that is of significance for strong shock prediction.The analysis of the earthquake catalogue of China in 1987-1988 by using this method shows that only two burst events occurred in the aftershock area of the 1976 Tangshan earthquake in this period. So it is expected that there will not occur shocks with M>6.5 in tne north part of Huabei area in 1989.
出处
《地震》
CSCD
北大核心
1990年第1期37-42,共6页
Earthquake
