Crustal velocity structure from surface wave dispersion tomography in the Indian Himalaya

A network of 15 broadband seismographs in a ~500 km long, N-S array recorded 12 months of data in 2002-2003. The array traverses the NW Himalaya, from the Indian plain in the south, across the Indus-Tsangpo Suture and the Tso Morari Dome, to the southern flank of the Karakoram in the north. Magnetotelluric (MT) studies in this region reveal low-resistivity zones which may be indicative of fluids, graphite, or partial melts in the mid-crust. We have tested these hypotheses by creating 1-D models of crustal shear wave velocity. The models contain low-velocity zones at 25–40 km depth; these may be indicative of fluids or partial melts.