Velocity Estimation by Waveform Tomography in the Canadian Foothill - A Synthetic Benchmark Study

In the structurally complex Canadian foothills, conventional seismic data processing is inadequate, given the effects of steep dips, rough topography, and near-surface weathering. Depth imaging is often necessary, and an accurate estimation of the macro-velocity model is essential. Waveform Tomography (i.e., traveltime tomography followed by frequency-domain waveform inversion) of long-offset data provides a possible solution. In order to investigate this, we generated synthetic data in a geologically realistic model exhibiting fold-thrust sheets, steeply dipping structures, and topographically elevated carbonate outcrops. The method shows promise for resolving the near-surface geological structures in this environment. Real data acquired with long-offsets and low-frequency sensors may provide the necessary input for Waveform Tomography to succeed in the Canadian foothills.