Refining Moho Depth Estimates from Receiver Functions, introducing variable Weights for P-to-S converted Phases

Accurate determination of the Moho depth and seismic velocities is essential for understanding the Earth's crustal structure and geodynamic processes. A widely used approach for estimating Moho depth is the H-k stacking method. H-k stacking makes use of receiver functions and a grid search to identify which values of Moho depth and crustal V_P/V_S ratio are able to best reproduce arrival times of P-to-S converted phases, recorded in the Receiver Functions. Due to the crustal attenuation and local scattering, multiple converted P-to-S phases, namely PpPs and PsPs+PpSs, generally display lower amplitude with respect to P-to-S phase. To fully take into account this observation, the different P-to-S converted phases are given different importance (i.e. different weights) during the H-k stacking. However, such assumption can introduce bias due to the user-defined weights assigned to the different phase arrival times.

To address this limitation, we propose a novel algorithm that extends the traditional H-k stacking approach by introducing two additional dimensions: variable weights for the phase arrival times. This innovation enables us to compute H-k grids using a range of weight configurations and evaluate their probability. The optimal grid is selected based on its probability, thus we reduce the influence of subjective weight assignments.

By incorporating variable weights into H-k stacking, our approach aims to reduce bias and improve the robustness of Moho depth estimates. With this enhanced method we hope to contribute to a more precise picture of the Earth's crust and a better understanding of geodynamic processes.