Northeast Tibetan Crustal Structure from INDEPTH IV Controlled- Source Seismic Data

Abstract

76 Since 1992, project INDEPTH (International Deep Profiling of Tibet and the Himalaya) geoscientists from Chinese, American, British, German, and Canadian institutions have collaborated to collect high-quality seismic, MT, and geologic data along a roughly north–south transect from the Himalaya to northern Tibet. The current field effort from 2007–2009, INDEPTH IV, targets the NE margin of the plateau, with goals of testing models of subduction (relict and current) near the Kunlun and Jinsha sutures and probing the deep geometry of key features such as the Kunlun and Altyn Tagh Faults. Our new datasets are intended to shed light on the possible existence of a lower-crustal flow channel beneath northern Tibet, analogous to the weak (and flowing?) lower crust evidenced by INDEPTH observations of mid-crustal low seismic velocities, seismic bright spots and high electrical conductivities (Nelson et al. 1996) in southern Tibet. INDEPTH IV further aims to evaluate the possible subduction of Asian crust from the north beneath the Kunlun suture (Kind et al. 2002) and to probe whether the Kunlun and Jinsha sutures act as crustal-scale faults. Active seismic experiment, summer 2007