远震波场正演模拟方法及应用  

Forward modeling method and application of teleseismic wavefield

作　　者：桑莹泉 刘有山[1,3] 徐涛[1,3] 白志明[1,3] 解桐桐[1,2] Sang Yingquan;Liu Youshan;Xu Tao;Bai Zhiming;Xie Tongtong(State Key Laboratory of Lithospheric Evolution,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China;University of Chinese Academy of Sciences,Beijing 100049,China;Innovation Academy for Earth Science,CAS,Beijing 100029,China)

机构地区：[1]中国科学院地质与地球物理研究所,岩石圈演化国家重点实验室,北京100029 [2]中国科学院大学,北京100049 [3]中国科学院地球科学研究院,北京100029

出　　处：《地球与行星物理论评》2021年第6期569-586,共18页Reviews of Geophysics and Planetary Physics

基　　金：国家自然科学基金资助项目(41774100,41874065,41804060)。

摘　　要：地震波场数值模拟是壳幔结构成像和深部探测的重要基础.经典的远震波场数值模拟主要基于一维地球模型,包括解析法、半解析法和数值法等.这些算法能够高效地计算理论地震图,但由于将地球假设为一维层状介质,难以考虑介质的横向非均匀性对地震波场的影响.近年来随着计算机性能的不断提高,三维地震波场数值模拟方法得到快速发展,并被广泛用于局部/区域地震波场模拟及壳幔结构成像.然而由于计算成本较高,实现全球尺度模型的高频地震波场数值模拟仍存在较大挑战,因而基于远震波场的混合数值模拟方法逐渐得到关注和应用.远震波场混合数值模拟法将全球模型分解为全球区域和局部区域,在全球区域中采用一维地球模型近似,应用快速算法计算一维模型中的全球高频理论地震图;在局部目标区域内采用三维数值方法(谱元法、有限差分法等)和注入技术,模拟地震波在三维非均匀介质中的传播,从而在波场计算的效率和精度之间达到平衡.随着密集台阵观测的普及,对地下结构成像的分辨率提出了更高的要求,准确高效的远震波场混合模拟方法在高分辨率地震成像领域将发挥日益重要的作用.本文系统地总结了远震波场数值模拟的一维模拟方法,并在此基础上重点介绍远震波场混合数值模拟方法的原理及应用.Seismic wavefield numerical simulation is an important base for crust-mantle structure imaging and deep exploration.The classical teleseismic wavefield simulation methods,including analytical method,semi-analytical method and numerical method,are mainly based on one-dimensional Earth model.These algorithms can efficiently calculate the synthetic seismogram,but the lateral heterogeneity of the medium is not being incorporated.With the improvement of computer performance,numerical simulation methods for three-dimensional seismic have been developed rapidly,and have been widely used in both local and regional seismic wave simulations.But due to the limitation of computing resources,the implementation of high frequency seismic wavefield numerical simulation based on global scale is still a great challenge.In recent years,hybrid numerical simulation methods of teleseismic wavefield have been developed,in which the target simulation region is decomposed into two scales(global scale and local scale).In global scale,high-frequency synthetic seismogram is calculated through fast algorithm based on one-dimensional earth model assumption.With injection method,three-dimensional numerical methods(spectral element method,finite difference method,etc.)are used to simulate the propagation of seismic wave in three-dimensional heterogeneous medium in local target scale,to achieve the balance between efficiency and accuracy.With the development of dense array observation,scientific research puts forward higher requirements for the resolution of underground structure imaging.Accurate and efficient hybrid simulation method of seismic wavefield will play an important role in the field of high-resolution seismic imaging.In this paper,we systematically summarize one-dimensional simulation methods of teleseismic wavefield numerical simulations,as well as the principle and application of hybrid numerical simulation methods of teleseismic wavefield.

关 键 词：远震波场模拟 壳幔结构成像 理论地震图 混合法 

分 类 号：P315[天文地球—地震学]