基于ETAS模型的余震概率性地震危险性分析  

Aftershock probabilistic seismic hazard analysis based on ETAS model

作　　者：陈力波[1] 陈良鹏 周健鸿 CHEN Libo;CHEN Liangpeng;ZHOU Jianhong(College of Civil Engineering,Fuzhou University,Fuzhou 350116,China)

机构地区：[1]福州大学土木工程学院,福建福州350116

出　　处：《自然灾害学报》2024年第4期22-33,共12页Journal of Natural Disasters

基　　金：福建省自然科学基金面上项目(2020J01478)。

摘　　要：余震概率性地震危险性分析对主震发生后的地震风险评估至关重要。经典的余震概率性地震危险性分析框架基于Reasenberg-Jones(R-J)模型建立,但R-J模型对复杂的地震序列可能存在预测失效的问题,因此,将对真实余震序列描述较好的传染型余震序列模型(epidemic-type aftershock sequence,ETAS)结合到余震概率性地震危险性分析框架中,以2008年汶川7.9级余震序列和2014年鲁甸6.2级余震序列为例,评估余震危险性的重要性以及探讨ETAS模型相对于R-J模型在余震概率性地震危险性分析中的差异。结果表明:余震危险性水平与主震震级大小有关,主震震级越大,余震危险性水平越高,持续时间越久,对于震级较大的强主震事件,主震发生后早期的余震危险性不容忽略。对于汶川7.9级和鲁甸6.2级地震事件,在余震发生率预测效能上ETAS模型优于R-J模型,而在余震危险性评估中,余震危险性的大小取决于余震发生率,基于R-J模型计算的余震发生率大于ETAS模型计算的余震发生率,因此,在余震危险性评估中使用R-J模型相比于ETAS模型会造成对余震危险性水平的高估,ETAS模型可用于改进余震概率性地震危险性评估框架。Aftershock probabilistic seismic hazard analysis is of vital importance in seismic risk assessment after the mainshock.The conventional framework for such analysis relies on the Reasenberg-Jones(R-J)model.However,it is known that the R-J model may exhibit shortcomings in predicting complex seismic sequences.Therefore,this study integrates the epidemic-type aftershock sequence(ETAS)model,which provides a more comprehensive representation of real-world aftershock sequences into the framework of aftershock probabilistic seismic hazard analysis.To demonstrate this integration,two real-world scenarios were examined including the aftershock sequence following the 7.9 magnitude Wenchuan earthquake in 2008 and the aftershock sequence after the 6.2 magnitude Ludian earthquake in 2014.The purpose is to highlight the significance of evaluating aftershock hazard levels and to investigate the differences between the ETAS model and the R-J model in the context of probabilistic seismic hazard analysis for aftershocks.The results underscore the correlation between the hazard levels of aftershocks and the magnitude of the mainshock.Notably,larger mainshock magnitudes are associated with elevated aftershock hazard levels and prolonged durations.For substantial mainshock events with higher magnitudes,the hazard posed by early-stage aftershocks following the mainshock cannot be disregarded.Furthermore,the result reveals that the ETAS model outperforms the R-J model in terms of predicting aftershock incidence for the Wenchuan earthquake and the Ludian earthquake.In the assessment of aftershock hazard,the magnitude of such hazard is contingent upon the rate of aftershock incidence.It is noteworthy that the aftershock incidence by using the R-J model exceeds that derived from the ETAS model.Consequently,employing the R-J model in aftershock hazard assessment leads to an overestimation of the level of aftershock risk compared to that of the ETAS model.The ETAS model can be utilized to enhance the aftershock probabilistic seismic hazard

关 键 词：ETAS模型 R-J模型 余震序列 余震概率性地震危险性分析 

分 类 号：P315.9[天文地球—地震学]