Observations from the Seafloor: Low-frequency Ambient Wavefield Seismology on Large Ocean-Bottom Nodal Arrays

 

Estimating accurate Earth models for 3-D seismic imaging and full waveform inversion (FWI) remains challenging due to limited low frequencies (i.e., below 2.0 Hz) typically available from active-source air gun arrays. Ambient wavefield energy acquired on large, continuously recording nodal arrays, though, presents a potential alternative energy source for subsurface investigation. By exploiting principles of seismic interferometry in deep-water marine settings, low-frequency virtual shot gathers (VSGs) from 1.0 Hz to as low as 0.04 Hz can be generated with surface-wave events that exhibit clear sensitivity to large-scale model features including salt bodies. The estimated VSG data also exhibit surface-wave scattering events consistent with the locations and depths of shallow salt pinnacles observed in active-source velocity model reconstructions. These observations suggest an alternative pathway forward for estimating long- (and potentially shorter-)wavelength 3-D elastic models required for accurate FWI and seismic imaging analyses.

Speaker: Jeff Shragge, Colorado School of Mines

Room 350/372

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