Waveform tomography – Marine vs Land: Targets, Challenges and Opportunities

Waveform tomography yields sub-wavelength scale velocity resolution through formal inversion of the recorded seismic wavefield. Velocity estimation through waveform inversion works best where wide angle (large offset) refractions and reflections are available in the input data, where low frequencies with good signal-to-noise rations are available, and where sources and receivers are adequately coupled and are reliably consistent. Waveform tomography results have been obtained by our group for both Marine and Land data settings. Marine seismic data, in most cases, lend themselves well to waveform tomography. Waveform tomography, especially where OBS recording are available, is ideally suited to provide geologically significant velocity images of deeper structures. Land seismic data, in contrast, pose significant challenges for waveform tomography particularly when topographic relief, weathering, and near-surface conditions are severe. The challenges afforded by land data mean that waveform tomography can require extensive manual intervention and repeated parameter testing, driving the costs up dramatically.