Three-component receiver function study of seismic array data from the Tibetan plateau

. Dense seismic arrays recently deployed on the Tibetan plateau have been widely used to study crust and mantle structure through traditional receiver function analysis. In this study we stack over all vertical waveforms associated with one earthquake to form the best estimate of the effective source time function. Stacking significantly cancels out the scattered wavefield after the direct P wave. The deconvolution of the stacked waveform from all three components then provides information both for P wave velocity structure from analysis of the vertical component and shear wave velocity structure from the horizontal components. Preliminary results show that three component receiver functions beneath INDEPTH-III stations are quite complicated. Strong reverberations within the upper crust are observed for most of the stations implying complicated 3D crust structure beneath the array. Vertical component receiver functions are often quite complex showing secondary arrival comparable in amplitude to the first P wave arrival suggesting large P wave reverberations in the shallow crust. Corresponding horizontal receiver functions are also very complex. It is likely that these upper crustal wave propagation effects much converted arrivals from deeper levels in the crust and mantle.