基于时间相依地震活动性模型的地震时间序列模拟

The simulation of earthquake sequence based on time-dependent seismicity model

模拟地震时间序列在地震危险性分析和地震灾害预测等领域中具有重要作用,地震活动性模型是模拟地震序列的重要理论基础.本文以时间相依地震活动性模型为理论模型,系统梳理了现有时间相依地震活动性模型理论与方法,研究了断层(震源)上最新地震发生时间已知、未知以及地震历史开放间隔已知三种情况下地震发生概率的计算方法,分析了地震复发间隔的变异系数对时间相依地震发生概率的影响.研究了基于布朗模型的特征地震准周期发生的物理原理,建立了时间相依地震时间序列的模拟方法.研究结果表明,在地震离逝时间较长的情况下,基于时间相依地震活动性模型计算的地震发生概率要显著大于泊松模型;在地震历史开放时间已知情况下,计算的地震发生概率要高于地震离逝时间未知的情况.地震复发间隔的变异系数越小,模拟的地震时间序列越呈现周期性.本文研究结果可提高长期地震概率预测水平,模拟的具有时间相依特征的地震时间序列可用于地震预测、概率地震危险性分析以及地震灾害预测等领域.

The simulation of seismic time series plays an important role in seismic hazard analysis and earthquake disaster prediction,while the seismicity model is an important basis of simulating seismic series.In this paper,taking the time-dependent seismicity model as the target model,we systematically summarize the theories and methods of the existing time-dependent seismicity model,study the calculation methods of the probability of earthquake occurrence in the three cases where the occurrence time of the latest earthquake on a fault(source)is known,unknown,and the known open interval of earthquake history,and analyze the influence of the uncertainty of earthquake recurrence interval on the probability of occurrence of time-dependent earthquakes.We also research the physical principle of quasi-periodic occurrence of characteristic earthquakes based on Brownian model,and establish the simulation method of time series of time-dependent earthquakes.The results show that the probability of earthquake occurrence calculated by the time-dependent seismicity model is significantly higher than that calculated by the Poisson model when the earthquake has a long lapse time;the probability of earthquake occurrence with the known opening time of earthquake history is higher than that calculated with the unknown lapse time of earthquake.The smaller the uncertainty of earthquake recurrence interval is,the more periodic the simulated time series of earthquakes will be.The results of our study can improve the long-term prediction level of earthquake rupture forecasts,and the simulated time series of earthquakes with the characteristics of time-dependent can be used in the fields of earthquake prediction,the probability seismic hazard analysis and earthquake disaster prediction,etc.