华北强震的时间分布及物理解释

本文讨论了华北地区M_s≥7级强震的时间分布,发现在每一个地震活动期内,大地震的累积频度曲线随时间的变化大致呈指数函数形式.文中用最小二乘法拟合了第三、第四两个活动期的累积频度曲线,用线性流变体简化模型对大震的时间分布作了理论解释.并从地壳和上地幔的环境方面探讨了第三和第四两个活动期中强震活动的差异性.本文的结果对研究地震活动分期、讨论大震趋势有一定参考作用,其理论探讨有助于分析一个活动期内强震孕育和发生过程.

TIME SEQUENCES OF STRONG EARTHQUAKES IN NORTH CHINA AND THEIR EXPLANATION

Time sequences of strong earthquakes during the 3rd and 4th seismic periods in North China were discussed in this paper. It shows that the change in accumulated frequency with time can be represented by an exponent function during each period. The relations were fitted by curves solved by the means of the least-S_quare method, and explained by using a Theology model theoretically. Also this paper tries to study the seis-micity difference between the 3rd and 4th periods in consideration of the state in the crust and mantle.The above results might be useful for studying division of seismic periods, discussing the, tendency of strong shock occurrence, and analysing the preparation and occurrenceprocess of strong shocks during a seismic period.