摘要
概率地震危险性分析是地震区划图编制、重大工程场地地震安全性评估以及地震风险管理等领域的重要依据,地震时间活动性模型则是概率地震危险性分析的主要理论基础.本研究中基于布朗过程时间(Brownian passage time(BPT))模型,计算了不同情况下中国大陆特征地震震源区时间相依的地震发生率,采用概率地震危险性计算方法,选择合适的地震动模型,评估了中国大陆地区时间相依的地震危险性,并与基于泊松模型的地震危险性做了比较.结果表明,时间相依的地震活动特征对概率地震危险性具有显著影响,在那些地震离逝时间相对较长,离逝率较大(大于1)的震源区,时间相依的地震危险性结果相较于基于泊松模型的地震危险性结果显著增大,增大幅度最大可达50%以上.相反,在那些刚发生地震不久,地震离逝时间较短的震源区,时间相依的地震危险性结果相较于泊松模型显著减小,减小幅度最大可达50%左右.地震复发间隔的变异系数对地震危险性结果也有显著影响,选择合适的变异系数对时间相依地震危险性分析十分重要,后续应该加强对地震复发间隔不确定性的研究.研究结果还表明,时间相依的地震活动特征对不同超越概率下的地震危险性结果的影响是一致的,不随超越概率水平的变化而变化.本文研究结果对地震风险管理、地震保险以及相关防震减灾政策的制定等方面具有重要的应用价值.
The results of probabilistic seismic hazard analysis are important basis for seismic hazard mapping,seismic safety assessment of major engineering sites and seismic risk management,etc.Seismic temporal activity model is the main theoretical basis for probabilistic seismic hazard analysis.In this study,we calculate the time-dependent seismic rate of the seismic sources of characteristic earthquakes in China's Mainland based on the Brownian Passage Time(BPT)model.By using the probabilistic earthquake hazard calculation method,we select an appropriate ground motion model to evaluate the time-dependent seismic hazard in China's Mainland.The results are compared with those based on Poisson model.Results show that the time dependent characteristic of earthquake has a significant impact on the result of the probability seismic hazard.Compared with the Poisson model-based seismic hazard results,the time-dependent seismic hazard results are significantly higher than those based on Poisson model in seismic source regions with relatively long elapsed time and large elapsed rate(greater than 1),with the maximum increase of more than 50%.On the contrary,the time-dependent seismic hazard results in the seismic source regions with short elapsed time are significantly reduced compared with Poisson's model,with a maximum reduction of about 50%.The coefficient of variation of earthquake recurrence interval also has significant influence on the seismic risk results,so the study on the uncertainty of earthquake recurrence interval should be strengthened.The results also show that the time-dependent seismic activity characteristics have a consistent effect on the seismic hazard results under different exceedance probabilities.The results of this study are an important supplement to the traditional time-independent(Poisson model)seismic hazard results,and have important significance for earthquake risk management,earthquake insurance and the formulation of earthquake protection and disaster reduction policies.
作者
徐伟进
吴健
高孟潭
XU WeiJin;WU Jian;GAO MengTan(Institute of Geophysics,China Earthquake Administration,Beijing 100081,China;China Earthquake Disaster Prevention Center,Beijing 100029,China)
出处
《地球物理学报》
SCIE
EI
CAS
CSCD
北大核心
2023年第12期5005-5018,共14页
Chinese Journal of Geophysics
基金
中国地震局地球物理研究所基本科研业务专项(DQJB22Z03,DQJB21Z07)资助
科技部重点研发计划项目“地震保险损失评估模型及应用研究”(2018YFC1504601)资助。
