The Signature and Elimination of Sediment Reverberations on Submarine Receiver Functions

While the receiver function technique has been successfully applied to high-resolution imaging of sharp discontinuities within and across the lithosphere, it suffers from severe limitations when applied to seafloor seismic recordings. This is because the water and sediment layer could strongly influence the receiver function traces, making detection and interpretation of crust and mantle layering difficult. This effect is often referred to as the singing phenomena in marine environments. We demonstrate, using analytical and synthetic modeling, that this singing effect can be reversed using a selective dereverberation filter tuned to match the elastic property of each layer. We apply the dereverberation filter to high-quality earthquake records collected from the NoMelt seismic array deployed on normal, mature Pacific seafloor. An appropriate filter designed using the elastic properties of the underlying sediments, obtained from prior studies, greatly improves the detection of Ps conversions from the Moho (∼8.6 km) and from a sharp discontinuity (<∼5 km) across the lithosphere asthenosphere transition (∼72 km). Sensitivity tests show that the dereverberation filter is mostly sensitive to the two-way travel time of the shear wave in sediment and is robust to seismic noise and small errors in the sediment properties. Our analysis suggests that selectively filtering out the sediment reverberations from ocean seismic data could make inferences on subsurface structure more robust. We expect that this study will enable high-resolution receiver function imaging of the oceanic plate across the growing ocean bottom seismic arrays being deployed in the global oceans.