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本文用京津地区跨断层短水准短基线测量资料,对近期断层的活动强度,活动方式及各不同方向断层之间的相互关系进行研究,从中探求了1976年唐山7.8级地震前,该区域断层活动的特征。结果表明,断层运动主要是以水平运动为主,但是总的活动强度不大。从断层活动量看,北北东和北东向断层大于东西向和北西向断层。 1973年底以前北北东向和北东向断层上大多数观测点显示出右旋活动,东西向断层为右旋活动,北西向断层为左旋活动,表明是受近东西方向作用力的结果。 1974年初以后,逐步出现了与1973年底以前断层的活动速率和方式不同的特点,这种变化很可能是唐山7.8级地震孕育过程在活断层上的一种反映。根据这种特征,提出了判别强地震中期异常的一种方法。
Based on the short stratum short-baseline data of straddling fault in Beijing-Tianjin area, this paper studies the intensity of the recent faults, the mode of activity and the interrelationships between the faults in different directions. From this study, it is explored that before the Tangshan earthquake of magnitude 7.8 in 1976, Characteristics of activities. The results show that the fault movement is mainly horizontal movement, but the total activity intensity is not large. According to the amount of fault activity, the north-north east and north-east faults are larger than the east-west and north-west faults. Before the end of 1973, most of the north-north-east and north-east faults show dextral activity at most observation points. The east-west faults are dextral activities and the north-west faults are left-handed faults, indicating that they are subject to the east-west force. After 1974, the characteristics of the velocity and the pattern of the faulting before the end of 1973 are gradually emerging. This change is likely to be a reflection on the active fault of the Tangshan 7.8-magnitude earthquake. According to this feature, a method of discriminating medium-term anomalies of strong earthquakes is proposed.