Sequential H-κ Stacking to Obtain Accurate Crustal Thicknesses beneath Sedimentary Basins

Low-velocity sedimentary basins introduce error in many standard receiver-function (RF) analysis techniques including common conversion point (Dueker and Sheehan, 1997) and crustal thickness-V-P/V-S ratio (H-kappa) stacking (Zhu and Kanamori, 2000). We describe a simple RF analysis method for obtaining accurate crustal thickness below seismic stations located in sedimentary basins. The method extends the methods of Zhu and Kanamori (2000). It employs an iterative two-layer depth-V-P/V-S stacking approach that first characterizes sediment properties (thickness and V-P/V-S) allowing for the accurate interpretation of Moho conversions. Without accounting for sedimentary layers, standard-RF analysis can mischaracterize crustal thickness based on Ps-phase delay by > 10 km beneath deep basins. We test the technique with synthetic seismograms and with data from US Array Transportable Array (TA) stations from regions with sediment thicknesses that are well determined through other means. We find sequential H-kappa stacking for sediment properties to be a simple technique that can benefit many RF-analysis studies and can play an important role in crustal seismic studies in areas with thick or variable sediments.