Application of Snell's law in reflection raytracing using the multistage fast marching method  

作　　者：Xingzhong Li Wei Zhang 

机构地区：[1]School of Earth and Space Sciences,University of Science and Technology of China,Hefei,Anhui,230026,China [2]Shenzhen Key Laboratory of Deepwater Oil and Gas Exploration Technology,Department of Earth and Space Sciences,Southern University of Science and Technology,Shenzhen,Guangdong,518055,China

出　　处：《Earthquake Research Advances》2021年第1期41-48,共8页地震研究进展（英文）

基　　金：This research is jointly sponsored by National Natural Science Foundation of China(Grant No.U1901602);Shenzhen Key Laboratory of Deep Offshore Oil and Gas Exploration Technology(Grant No.ZDSYS20190902093007855);Shenzhen Science and Technology Program(KQTD20170810111725321);This study is also sponsored by the China Earthquake Science Experiment Project of China Earthquake Administration(Grant No.2018CSES0101).

摘　　要：Accurate calculations of travel times and raypaths of reflection waves are important for reflection travel time tomography.The multistage shortest path method(MSPM)and multistage fast marching method(MFMM)have been widely used in reflection wave raytracing,and both of them are characterized by high efficiency and ac-curacy.However,the MSPM does not strictly follow Snell's law at the interface because it treats the interface point as a sub-source,resulting in a decrease in accuracy.The MFMM achieves high accuracy by solving the Eikonal equation in local triangular mesh.However,the implementation process is complex.Here we propose a new method which uses linear interpolation to compute the incident travel time of interface points and then using Snell's law to compute the reflection travel time of grid points just above the interface.Our new method is much simpler than the MFMM;furthermore,numerical simulations show that the accuracy of the MFMM and our new method are basically the same,thus the reflection tomography algorithms which use our new method are easier to implement without decreasing accuracy.Besides,our new method can be extended easily to other grid-based raytracing methods.

关 键 词：reflection raytracing Snell's law TRAVELTIME reflection angle 

分 类 号：P315[天文地球—地震学]