Influence of wave front healing on seismic tomography  

作　　者：Liu YuZhu Dong LiangGuo 

机构地区：[1]State Key Laboratory of Marine Geology,Tongji University,Shanghai 200092,China

出　　处：《Science China Earth Sciences》2012年第11期1891-1900,共10页中国科学（地球科学英文版）

基　　金：supported by National Natural Science Foundation of China(Grant No. 40804023);National Basic Research Program of China (Grant No. 2006CB202402);Hi-tech R&D Program of China (Grant No.2008AA093001);Project of State Key Laboratory of Marine Geology of China (Grant No. MG200909)

摘　　要：Wave front healing is a common natural phenomenon.To further investigate wave front healing,we simulated wave propagation in a spherical anomaly surrounded by homogeneous media using a high-order finite difference solution of the acoustic equation.Furthermore,we analyzed the characteristics of the wave propagation in the anomaly,and found that they are related to the dominant frequency of the seismic wave and the dimensions of the anomaly.Through quantitative comparison of the wave front energy of the diffracted wave and transmitted wave,we summarized the influences of the wave front healing on seismic tomography.We conclude that,under the strong scattering condition,only positive anomalies can be inverted by ray-based tomography,only large anomalies can be inverted by finite-frequency tomography,and small negative anomalies cannot be inverted by any first-arrival traveltime tomographic methods.These conclusions are verified by tomographic experiments based on different theoretical models.Finally,we propose that more information besides the first-arrival traveltime should be used to invert the high wave number components of the media.Besides the above acquisitions of wave front healing on seismic tomography,we explain the banana-doughnut phenomena,and offer a new insight into the wave scattering,which should be important for better understanding the wave propagation and seismic inversion.Wave front healing is a common natural phenomenon.To further investigate wave front healing,we simulated wave propagation in a spherical anomaly surrounded by homogeneous media using a high-order finite difference solution of the acoustic equation.Furthermore,we analyzed the characteristics of the wave propagation in the anomaly,and found that they are related to the dominant frequency of the seismic wave and the dimensions of the anomaly.Through quantitative comparison of the wave front energy of the diffracted wave and transmitted wave,we summarized the influences of the wave front healing on seismic tomography.We conclude that,under the strong scattering condition,only positive anomalies can be inverted by ray-based tomography,only large anomalies can be inverted by finite-frequency tomography,and small negative anomalies cannot be inverted by any first-arrival traveltime tomographic methods.These conclusions are verified by tomographic experiments based on different theoretical models.Finally,we propose that more information besides the first-arrival traveltime should be used to invert the high wave number components of the media.Besides the above acquisitions of wave front healing on seismic tomography,we explain the banana-doughnut phenomena,and offer a new insight into the wave scattering,which should be important for better understanding the wave propagation and seismic inversion.

关 键 词：finite-frequency Fresnel volume tomography scattering condition seismic inversion wave front healing 

分 类 号：P631.4[天文地球—地质矿产勘探] TP212[天文地球—地质学]