On Receiver Functions with Sediment Reverberations

Summary Teleseismic P-wave receiver function (RF) analysis is a powerful tool for probing deep structures; however, its application to regions with sedimentary cover remains challenging. The interference by converted and reflected waves related to the sediments can form strong reverberations and render individual phases unidentifiable, complicating the investigation of sedimentary structures. Moreover, the strong, long-lasting sediment-induced waves can mask seismic phases from deeper layers, making it difficult to investigate the underlying layers. We investigated all the phases in RFs and establish simple relationships between the underlying layer structure and the phases and phase groups. By measuring the times of all phases and phase groups or stacking the amplitudes of all phases, we can investigate the structure more reliably; however, when interference is so strong that the peaks and troughs do not align with individual phases, the models resulting from using these phases may contain significant uncertainty. In these cases, simple RF waveform fitting constrained by the one-way vertical travel time (the product of wave vertical slowness and layer thickness) or the period of the phase groups associated with the sedimentary layer can resolve the sedimentary structure reliably. Deconvolving the P-wave RFs predicted by the resulting sedimentary model from the original RF can remove the sedimentary waveforms effectively and correct the sediment-induced delays in deeper-layer phases. We demonstrate the effectiveness of our proposed approaches for inverting the structure and removing the sedimentary response using both synthetic and real data.