This is an innovative package for Surface wave Adjoint Travel-time Tomography driven by modern fortran with highlights:

• Calculation of surface wave travel time based on Eikonal equation with fast sweeping method (Tong, 2021a)
• Computation of sensitivity kernels through adjoint method (Tong, 2021b)
• Multi-grid model parametrization utilization in optimization (Tong et al., 2019)
• Consideration of surface topography (Hao et al., 2024a)

Please refer to the installation guide for detailed instructions.

The executable file bin/surfatt_tomo for inverting surface dispersion data for S-wave velocity can be run with mpirun as:

mpirun -np 4 bin/surfatt_tomo -i input_params.yml

A case named test/00_checkerboard_iso presents an example of inversion for 2x3x2 checkers using ambient noise surface wave data from 25 stations. execute run_this_example.sh to run this example under 8 processors.