Waveform Fitting of Receiver Functions for Enhanced Retrieval of Crustal Structure in the Presence of Sediments

Abstract

The receiver function technique is widely used to image crustal structure using P-to-S converted phases at the Moho discontinuity. However, the presence of sedimentary layer generates additional P-to-S conversions and reverberations, which can overprint the Moho phases and pose problems in imaging crustal structure with standard receiver function techniques. We introduce a robust two-step method that uses H-κ stacking to determine average thickness and Vp/Vs of the sedimentary layer, followed by waveform-fitting of the observed receiver function to constrain the average crustal thickness and sub-sediment Vp/Vs. We tested the method using both synthetic data and real-data from stations located on sedimentary layers in the Netherlands and USA. We show that the new method outperforms other common approaches in retrieving accurate Moho depth and sub-sediment Vp/Vs estimates, even in cases where the Moho phases are completely overprinted by large-amplitude phases related to sedimentary layers.