Wavefront tomography for passive seismic data

We propose a workflow for velocity model building based on passive seismic data. The under-lying tomographic inversion makes use of the slopes and curvatures of the recorded wavefield and inverts for velocities, source locations and source excitation times simultaneously. Owing to the intrinsic robustness of coherence analysis, which constitutes the initial step of the method, our approach can deal with high levels of noise and sparse data. It does not require detailed a priori information and represents an adequate tool for retrieving an initial estimate of the over-burden velocities and, considering the passive events, the respective source locations.