for tracking phases comprising any number of reflection and transmission branches in complex layered media. Uses fast marching to compute traveltimes, and can also generate raypaths and Frechet derivatives.
Traditional methods of seismic tomography represent structure in terms of regular grids or truncated Fourier series, both of which may be inconsistent with the inhomogeneous distribution of data that characterizes most seismic surveys. In such circumstances, the extraction of structural information from the data is not maximized. With an inhomogeneous distribution of data, the minimum wavelength of structure that can be resolved varies both spatially and directionally; only an irregular parameterization is capable of capturing such information.
We simultaneously invert for 1-D P and S-velocity models inside each tectonic region of Earth, each defined with by iregular 3-D parameterization. A description of the RUM project with figures and results can be found here.