一引言 1976年7月28日在我国唐山发生了震级为7.8级地震。此次地震属于板内地震,也不是发生在深大断裂上。地震前没有明显的前震活动。本文的目的是探讨对于没有明显前震活动的大震在地震活动性方面可能存在的异常。所选用的资料取自国家地震局分析预报中心的库存目录。二震前的地震活动性异常 (一) 地震活动性的时空图象 1.条带唐山地震是一次没有直接前震的主余震型大震。为寻找震前地震活动性的异常,我们选 I. INTRODUCTION A magnitude 7.8 earthquake struck Tangshan in our country on July 28, 1976. The earthquake belongs to an intra-plate earthquake and does not occur on deep faults. There is no obvious foreshock activity before the earthquake. The purpose of this paper is to explore possible anomalies in seismicity for large earthquakes that have no significant foreshock activity. Selected data from the National Seismological Bureau forecast center inventory catalog. Seismic Anomalies Before Second Earthquake (I) Time-space Images of Seismicity 1. Band Tangshan earthquake is a major aftershock-type earthquake without direct foreshock. In order to find the anomalies of seismicity before the earthquake, we choose