关键词: 序列衰减, 余震激发, 修改的大森公式, ETAS模型, BASS模型

Abstract: Focusing on decay and generation of the aftershock activity,the latest theoretical advancements and applications on the modified Omori law,the ETAS model and the BASS model have been introduced in this paper. Up to now,the modified Omori law is the best formula for fitting the temporal decay of aftershock activity,which has been used to describe the decay characteristics of aftershock sequences quantitatively. Essentially,the modified Omori law is a typical statistical model on observing phenomena,but it has been used widely in practice owing to its less parameters,simple calculation,and higher capability of describing the general features of sequence decay. ETAS model,which takes into account the generation of the high order aftershocks with statistical self-similar characteristics,is a physical expansion of the modified Omori law,and the generation intensity of high order aftershocks is concerned to be related to the magnitude of the father earthquake. Since considering the problems of high order aftershock generation,ETAS model not only has a large improvement in study field of aftershock sequences,but also has many other applications,such as detection of relative quiescence,removing of the cluster aftershock activity,assessment of background seismicity,detection of seismic activity triggered by external factors and so on. BASS model follows the modified Bath's law,while the ETAS model follows the similar rate with the magnitude of the father earthquake,this is the largest difference between ETAS model and BASS model. So,the BASS model is a completely self-similar theoretical model compared with the ETAS,but only few papers concerning its application.

Key words: decay of aftershock sequence, generation of aftershock, modified Omori law, Epidemic Type Aftershock Sequence model(ETAS model), Branching aftershock sequence model(BASS model)