TTBox: A MatLab Toolbox for the Computation of 1D Teleseismic Travel Times

Abstract

Since the MatLab software has become an increasingly popular tool in data processing in recent years, it would be nice to have a travel-time software that is directly accessible from MatLab routines and integrates smoothly into applications written in the MatLab programming language. This can be achieved in different ways. One is to write interface routines to existing software packages, such as the FORTRAN tau package (Buland and Chapman, 1983, hereafter referenced as the libtau.f library) or the Java-based TauP Toolkit (Crotwell et al. , 1999). Another possibility is to write a completely new set of routines in the MatLab programming language. This second approach is the one followed in the programming of TTBox , the Travel Time ToolBox for MatLab. The MatLab approach has the main advantage that the programming language is completely platform-independent. If low-level access to operating system and hardware is avoided, MatLab routines immediately run on every platform on which MatLab is running, so installation is reduced to copying the files and adding a directory to the search path. Also, since MatLab encompasses many powerful plotting routines, it is also easy to include routines that plot input velocity models, resulting travel times, and ray paths and other curves. Export of graphs in any standard format is also provided by the MatLab environment. One important development goal for TTBox was to be able to change the input velocity model easily and quickly, and to compute travel times for different planets, especially the Moon and Mars. This was achieved by avoiding precomputed tables and by including information on the planet in velocity model files. The planetary radius is the most important datum in this context (details of file formats are given in a later section). The first section of this paper outlines the theoretical background of computations …