二维地层结构和速度的走时反演

介绍了在倾斜均匀各向同性层状介质情况下,根据地震反射走时反演二维地层结构和地层速度的地震射线层析成像方法——走时反演。正演模型射线追踪是根据Fermat原理实现的,即求解满足该原理的非线性方程组得到射线与界面的交点,进而计算相应的走时。反演是先假设一初始模型,用最优化方法使射线追踪走时与观察走时的残差极小。最后计算了分辨矩阵和信息密度矩阵,以评价反演结果。对有噪情形也进行了反演。

TRAVELTIME INVERSION FOR 2 - D SUBSURFACE STRUCTURE AND VELOCITY

This paper introduces that based on seismic traveltime data, the traveltime inversion, i. e. the seismic ray tomography, can be estimated the 2 - D subsurface structure and interval velocity in homogeneous, isotropic, slant-layered medium. The forward modelling is performed by ray - tracing based on Fermat's principle, i. e. to determine the intersection of rays and interfaces by solving the non -linear equations which satisfy this principle, and then to calculate corresponding traveltime. The inversion starts to guess an initial model, then to find an earth model when the traveltime residuals of calculated data and observed data are minimized by the optimization method. Finally, we calculated the information density matrix and resolution matrix in order to evaluate the inversion results. For the noise cases, the inversion is also processed.