Acknowledgements

We would like to thank the chief editor Jyoti Behura, Ryan Swindeman, Jitao Ma, Tingting Liu, Karl Schleicher, Josef Paffenholz and two anonymous reviewers for helpful discussions and constructive suggestions that improve the grammar and configuration of the paper a lot Yangkang Chen would like to thank Texas Consortium for Computational Seismology (TCCS) for financial support. This paper was prepared in the Madagascar open-source platform (Fomel et al., 2013) and all the examples are reproducible.