The Signature and Elimination of Sediment Reverberations on Submarine
Receiver Functions
Abstract
While the receiver function technique has been successfully applied to
high-resolution imaging of sharp discontinuities within and across the
lithosphere, it has been shown, however, that 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. Here, we show how one can silence this
singing effect. We demonstrate, using analytical and synthetic waveform
modeling, that this singing effect can be reversed using dereverberation
filters tuned to match the elastic property of each layer. We apply the
filter approach to high-quality earthquake records collected from the
NoMelt seismic array deployed on normal, mature (~70 Ma)
Pacific seafloor. An appropriate filter designed using the elastic
properties of the underlying sediments, and obtained from prior studies,
greatly improves the detection of Ps conversions generated 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
filter is robust to small errors in the sediment properties. Our
analysis suggests that appropriately 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 base of the oceanic
plate across a growing fleet of ocean bottom seismic arrays being
deployed in the global oceans.