采用块状建模以及三角形拼接的界面描述方式，并通过立方体速度网格线性插值获得块体内部的速度分布。正演过程中采用逐段迭代射线追踪方法计算三维复杂地质模型中的射线走时，并采用模拟退火方法进行了三维模型中的地震波走时反演研究。模型测试结果表明，使用的射线追踪和走时反演算法有效。

Seismic traveltime tomographic inversion has played an important role in detecting the internal structure of the solid earth. We use a set of blocks to approximate geologically complex media. The geological body is described as an aggregate of arbitrarily shaped blocks,which are separated by triangulated interfaces. We define the velocities at the given rectangle grid points for each block,and the heterogeneous velocities in each block can be calculated by a linear interpolation algorithm. We implement a segmentally iterative ray tracer(SIRT)to calculate traveltimes in the 3D heterogeneous block models. The simulated annealing method is employed in seismic traveltime inversion of 3D velocity model. Numerical tests indicate the effectiveness of our methods of ray tracing and traveltime inversion.

P315

国家自然科学基金（41604054、4274062）、中国地震台网中心青年科技基金课题（164040132051906）共同资助