说明：  该软件包以二维球壳坐标（恒定半径，可变纬度和经度）分配迭代非线性旅行时层析成像代码。 该代码的一种可能的应用是表面波断层摄影，例如使用从环境地震噪声场提取的高频间隔瑞利波形的旅行时间。 使用称为快速行进方法（FMM）的基于网格的eikonal解算器来解决前向问题，并且使用子空间反演方法来解决逆问题。 请注意，该代码不适用于需要考虑地球极点或其周期性的模型。 该软件是用Fortran 90编写的，并使用shell脚本迭代地应用各种代码以解决完整的非线性层析成像问题。 该代码已经在许多平台上进行了测试，并且可以在大多数计算机上运行，这些计算机可以访问由GNU，NAG，Portland，Pathscale，Intel，Fujitsu和Sun等分发的编译器。
(This package distributes an iterative non-linear traveltime tomography code in 2-D spherical shell coordinates (constant radius, variable latitude and longitude). One possible application of the code is surface wave tomography using, for example, traveltimes of high frequency interstation rayleigh waveforms extracted from the ambient seismic noise field. The forward problem is solved using a grid based eikonal solver known as the fast marching method (FMM), and the inverse problem is solved using a subspace inversion method. Note that the code is not suitable for models which require the Earth's poles or its periodicity to be taken into account. The software is written in Fortran 90, and uses shell scripts to iteratively apply the various pieces of code in order to solve the complete non-linear tomography problem.)