## rj-TOMO

### Summary

This software performs 2-D transdimensional travel time tomography using the algorithms described by Bodin (2012). It makes use of the Fast Marching wavefront construction techniques of Rawlinson & Sambridge (2004) and deKool et al. (2006). It is suitable for a range of 2-D spatial problems, and has previously been applied to ambient noise inversion, and travel time imaging of the layer above the Core Mantle Boundary.

The transdimensional nature of the inversion procedure allows the model parameterization to varying as part of the solution. The Reversible jump Markov chain Monte Carlo algorithm is used to generate an ensemble of low resolution candidate solutions to the inverse problem. The point wise spatial mean of the ensemble of Earth models is used as a representative image of the solution. The spatial resolution of this image is variable and controlled by the data. The variance of the ensemble of models at each point in the medium provides information on uncertainty. Multiple data sets may be combined with the data level noise of each being a variable during the inversion.

The Fortran 90 source code is included and parallelization is achieved through use of MPI calls. It has been run successfully on clusters of up to 1000 cores. Instructions for use and some examples are included. For examples of applications see the papers below.

*Figure*

### Download

The 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 tomo-0.9.16.tar.gz|tar xvf -`

The README file provides information on installation, documentation and examples.

### References

"Transdimensional Approaches to Geophysical Inverse Problems", Thomas Bodin, PhD Thesis, Australian National University, October 2010.

"Multiple reflection and transmission phases in complex layered media using a multistage fast marching method", Rawlinson, N., and Sambridge, M., Geophysics, 69, No. 5, 1338-1350, doi:10.1190/1.1801950, 2004.

"A practical grid based method for tracking multiple refraction and reflection phases in 3D heterogeneous media", de Kool, M., Rawlinson, N. and Sambridge, M., Geophy. J. Int., 167, 253-270, doi:10.1111/j.1365-246X.2006.03078.x, 2006.

"Seismic tomography with the reversible jump algorithm", Bodin, T., and Sambridge, M., Geophys. J. Int., 178, 1411-1436, doi:10.1111/j.1365-246X.2009.04226.x, 2009.

"Global P-wave tomography of Earth's lowermost mantle from partition modeling",
Young, M.K., H. Tkalčić, T. Bodin and M. Sambridge,
*J. Geophys. Res.*,
doi:10.1002/jgrb.50391, 2013.

"Strong, multi-scale heterogeneity in Earth's lowermost mantle",
Tkalčić, H., M.K. Young, J.B. Muir, R. Davies and M. Mattesini,
*Scientific Reports - Nature*, 5,
doi:10.1038/srep18416, 2015.