A unified map of Moho depth and V p /V s ratio of continental China by receiver function analysis

Abstract

Continental China consists of a complex amalgamation of geotectonic units and has expe- rienced strong and widespread tectonic deformation since the Mesozoic. To understand its geological structure better, we conducted a systematic receiver function analysis using a total of 83 509 teleseismic traces in the time period of 2009–2010 recorded by 798 broad-band stations, among which 749 stations are permanent digital seismic stations from China Earth- quake Networks Center and 49 stations were temporarily deployed in northern Central Tibet. A standard H–κ stacking method is employed to determine Moho depth and V p /V s ratio un- derneath each station from teleseismic receiver function analysis. The obtained Moho depth variationsaregenerallyconsistentwiththosedeterminedfromvariousdeepseismicsoundings profiles.Wecombineourresultswiththosefrompreviousreceiverfunctionsstudiestoproduce a high-resolution map of Moho depth and V p /V s variation for continental China. Compared to previous studies, the new study concerns many more stations and the resulting Moho depth map has much higher lateral resolution, especially in the eastern China. Overall, the Moho depth variation has a remarkable correlation with major tectonic units in continental China. For example, across the well-known gravity gradient line in east China, there is a clear shift in Moho depths. In general, the map of V p /V s ratio shows relatively high anomalies underneath Tibetan Plateau, along the gravity gradient line, and under several volcanoes.