Research School of Earth Sciences
Earth Physics


Teleseismic tomography uses relative arrival time residuals from distant
earthquakes to image wavespeed variations in the upper mantle beneath a seismic
array. The code distributed here is unique in that it uses the Fast Marching Method
(FMM) to compute traveltimes and paths through the 3D model. FMM is a grid based
eikonal solver that combines computational speed and robustness. The inverse
problem is solved using a subspace inversion method which is also fast and robust.
The forward and inverse steps can be used iteratively in order to address the
nonlinear nature of the tomographic inverse problem. Spherical coordinates are
used to account for the curvature of the Earth. Like most teleseismic
tomography codes, traveltimes from the distant source to the edge of the 3D model
are computed using a global reference model. In our case, we use ak135, although
other models could be substituted.
The teleseismic tomography code is written mainly in Fortran 90, although some
Fortran 77 code is used for computing ak135 traveltimes. The code has been tested
on a number of platforms, and should work on most computers that have acces to
compilers distributed by the likes of GNU, NAG, Portland, Pathscale, Intel,
Fujitsu and Sun. An extensive instruction manual can be downloaded by clicking on the
link below; this manual is also provided with the distribution.

Page last updated: 2005 December 07 Please direct all enquiries to: nick@rses.anu.edu.au Page authorised by: Coordinator, Earth Physics, RSES 
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