oa First arrival traveltime tomography for complex near-surface velocity structures

Classical algorithms used for travel time tomography are not necessarily well-suited for handling very large seismic data sets, densely parameterized velocity models and for taking advantage of current supercomputers architecture. We revisit the classical approach of firstarrival travel time tomography by proposing to use a simple gradient-based approach without the need of estimating the inverse of the Hessian of the misfit function. The gradient-based approach is very attractive from a numerical point as it can handle large data sets and velocity models and is very robust with respect to the choice of the initial velocity model.