3D Fast Marching

Overview

The 3-D Fast Marching package models seismic wave front propagation using the fast marching method (FMM) in 3-D spherical coordinates for complex layered media. Traveltimes and ray paths of phases comprising one or more bounces and/or transmissions can be tracked in the presence of complex structures (e.g. subduction zones, heterogeneous crust). Direct transmissions in continuous media can also be tracked. The main goal of the package is to act as a general tool for computing traveltimes in laterally heterogeneous media at a variety of scales; example applications include local or regional scale tomography (the software already includes an option to calculate the Frechet derivatives), refraction/wide-angle reflection imaging, and earthquake location.

Code

The adaptive stacking code is written in FORTRAN, and should run on most computers that have access to a fortran compiler. The complete source code can be downloaded here. Enquires should be directed to the author. You will need to register with iEarth prior to download.

To unpack the contents of this file, type something like:

gunzip -c fm3d_07.tar.gz | tar xvof -

The contents of the tar archive will be placed in a subdirectory called fm3d_07.

Version 0.7 was last updated in 2007. Version 0.4 of the code may still be downloaded, but we strongly recommend using version 0.7, as it has experienced a longer de-bugging period and introduces several new features.

The paper below gives describes the multi-stage fast marching method and its implementation in the code presented here. We suggest that you look through this paper before trying to use the program. Several terms used in the README file are also defined in this paper.

Papers

A practical grid-based method for tracking multiple refraction and reflection phases in three-dimensional heterogeneous media., de Kool, M., Rawlinson, N. and Sambridge, M.Geophys. J. Int., 167 , 253-270, 2006. doi:10.1111/j.1365-246X.2006.03078.x