Attenuating the ice flexural wave on arctic seismic data

David C. Henley

The frozen surface encountered in arctic seismic exploration, while providing consistent coupling for sources and receivers, also contributes to one of the strongest known source-generated coherent noises. This noise, the ice flexural wave, originates in uniform plates of ice floating on liquid water, a situation commonly associated with both river channels and offshore sea ice. The flexural wave is both strong and often highly dispersed, the high frequency energy travelling at much higher velocity than that at low frequency. Because of its strength and dispersion, the flexural wave is difficult to attenuate with standard coherent noise methods. We demonstrate attenuation of this noise in the radial trace (R-T) domain, which provides a convenient framework for separation of dispersed linear noise from reflections. Using a set of field seismic data from Hansen Harbour in the MacKenzie Delta, we show significant attenuation of the ice flexural wave, in spite of the fact that the noise is substantially spatially aliased.