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数值模拟方法在地震预测研究中应用的初步探讨(Ⅱ)
PRELIMINARY STUDY ON APPLICATION OF NUMERICAL SIMU-LATION METHODS TO EARTHQUAKE PREDICTION RESEARCH(Ⅱ)
【摘要】 在地震危险性分析和预测研究中,随着数值模拟技术的进步和对地球动力学过程认识的不断深入,有可能发挥越来越重要的作用。数值模拟一个区域内部的构造变形,在正常时期与观测结果应该是比较接近的,而当局部地方处于孕震临界失稳状态时,其实测结果就有可能与模拟结果不协调,据此有可能为地震的中期至短期预测提供有价值的信息;应用数值模拟方法研究地震库仑应力变化,可模拟分析各种因素对库仑应力变化的大小和分布的影响,获得更接近实际的结果;计算机模拟合成地震目录是解决建立区域地震预测概率模型数据不足的有效方法,未来的发展方向应该是建立更接近实际的三维动力学模型,同时考虑多场耦合作用,模拟断层活动的规律。
【Abstract】 With the advances in simulation techniques and understanding of geodynamic processes,numerical simulation is likely to play an increasingly important role in the research of seismic hazard analysis and earthquake prediction.In this paper,on the basis of the paper "A preliminary study on the application of numerical simulation methods to earthquake prediction research(Ⅰ)",the possible application of uncoordinated deformation analysis,Coulomb stress changes and earthquake probability modeling to the study of earthquake prediction is further discussed.When rock deforms from the elastic into the yield stage,the system is in a critical unstable state,the rock movement may deviate from the normal track and become complicated.The study results show that,before Wenan earthquake(MS 5.1)on July 4,2006,GPS velocity was well consistent with the numerical simulation speed in most areas of North China,while there were some differences in some regions,especially in the northeast of the North China Plain block,where big inconsistency in movement characteristics occurred,resulting perhaps from the preparation of Wenan earthquake.Research on earthquakes triggered by Coulomb stress change is a focus problem now.Numerical simulation may play an important role in the analysis of Coulomb stress changes.By constructing three-dimensional dynamic model,the effect of various factors on the value and distribution of Coulomb stress change can be simulated,and more realistic results can be obtained.By numerical simulation of Coulomb stress changes to seismic activities beneath Sichuan Zipingpu reservoirs,it is found that with the increase of reservoir water storage time,the pore pressure diffusion in the effective additional stress field will be gradually expanded to the range of more than 10km underground.The regional effective additional stress field and seismic activities show different characteristics in several typical regions.The United States Southern California Earthquake Center has tried to study the earthquake probability as research objectives.It is worthy of referencing in China’s earthquake research.Computer simulation of synthetic earthquake catalog is an effective way to solve the lack of data.The future direction of development should be a more realistic three-dimensional dynamic model,taking into account the multi-field coupling between heat,fluid and etc.,improving hardware and software conditions and shortening the calculation time step,obtaining more complete information on fault movement,and simulating the fault activities.
【Key words】 earthquake prediction; numerical simulation; Coulomb stress; earthquake probability modeling; uncoordinated deformation;
- 【文献出处】 地震地质 ,Seismology and Geology , 编辑部邮箱 ,2011年03期
- 【分类号】P315.61
- 【被引频次】7
- 【下载频次】208