Constraints on complex crustal structures from gravity data and harmonic analysis of receiver functions

Abstract

SUMMARY The traditional H–κ stacking technique is often used to determine the crustal thickness (H) and Vp/Vs (κ) using multiple Moho converted P-to-S phases, but weak crustal multiples and variation of arrival time of crustal multiples in receiver function resulting from complex crustal structure, such as dipping interface and/or crustal anisotropy, can cause bias estimates leading to erroneous interpretations. In this study, we overcome these problems by combining the Ps arrival times in receiver functions and independent constraint from gravity data, providing a complementary to the H–κ method for estimating H and H with the advantage of not relying on the crustal multiples which are commonly hardly identified. Harmonic corrections are only made to arrival time variations of Ps phase before H–κ stacking. Independent gravity data can help constrain the trade-off between the H and κ when using Ps times only. Stacking these two complementary data sets allows us to yield a more accurate estimation of H and κ. The reliability and validity of our method to constrain the crustal properties are confirmed using synthetic data from multiple types of models and real data recorded by two permanent seismic stations belonging to different geological regions.