强余震的时间分布特征及其理论解释

分析了我国约五十年来发生的28个大震的余震序列。指出: 1、对于主-余震型地震序列,其强余震的“等待时间”（该强余震距上次强余震的时间）Δt与它的发生时间（距主震的时间）t遵从对数--对数线性关系: 其中:A≈0.92,B≈-0.11。 2、对于双主震或主震群型的地震序列则只有在最后一个主震发生后,Δt和t才有上述关系。 文中对上述特点在判断地震类型及预报强余震震中的应用,作了初步讨论。并利用流变学和断裂力学的观点,对这一现象作了初步的理论解释。

ON TEMPORAL DISTRIBUTION OF LARGE AFTERSHOCKS OF THE SEQUENCE OF A MAJOR EARTHQUAKE AND PRELIMINARY THEORETICAL EXPLANATION

Sequences of 28 major earthquakes occurred in China have been analyzed. It is found that:（1） For the mainshoek-aftershock type of earthquake sequence, there is a relation between the "waiting time" △t of a strong aftershock （so-called, as the time interval from its preceding strong aftershock） and the time of its occurrence t （time interval from the moment of onset of the mainshock）, namely,lg△t = Algt + B A=0.92, B= - 0.11（2） For a twin earthquake （two main shocks）-or a swarm of strong （more than two main shocks） earthquakes, such a relation becomes apparent only after the occurrence of the final main shock.A preliminary discussion has been made in connection with the applications of the above result in discerning the type of earthquake sequence and prediction of strong aftershocks following the major earthquake. Furthermore, based on the principles of rheology and fracture mechanics, a preliminary theoretical explanation of the relation between lg△t and lgt was attempted.