在前人研究的基础上,利用华北地区的地震资料,研究了1970~1976年华北地区地震视应变场的分布和时空演化特征。结果表明,1976年唐山地震与华北地区地震视应变的时空演变具有很好的对应关系。唐山地震发生在地震视应变异常区,在地震发生前的1970年就出现异常区,并且地震视应变总体上是逐年增加的,直到1976年地震发生。 Based on the previous studies, using the seismic data in North China, the distribution and temporal-spatial evolution of the apparent strain field in the North China from 1970 to 1976 were studied. The results show that there is a good correspondence between the Tangshan earthquake in 1976 and the temporal-spatial evolution of seismic strain in North China. The Tangshan earthquake occurred in an anomalous area of ​​seismic strain anomalies. Before 1970, anomalous regions appeared, and seismic strain was generally increased year by year until the 1976 earthquake.