Inverting for a 3D shear-wave velocity model of the Valhall subsurface - Results from seismic interferometry

We present a 3D Shear-wave velocity model of the subsurface at Valhall obtain using seismic interferometry. After computing the Scholte-wave group and phase velocity maps at different frequencies we obtained local dispersion curves at each point of our model. We used a Monte-Carlo approach to invert these local dispersion curves at depth as 1D S-wave velocity models. The collection of these models allowed us to create a 3D model. Our model that is well resolved down to 300 m below the sea level shows geomorphological features with very heterogeneous velocities and could be used as a starting model for Full Waveform Inversion. The monitoring of the shallow subsurface could also be a future application for ambient seismic noise based methods.