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Shear-Wave Velocity Structure Beneath North-Western Himalaya and Adjoining Areas

Session: Sensors, Seismicity and Imaging

Type: Oral

Date: 4/21/2021

Presentation Time: 06:00 PM Pacific

Description: 

Shear-wave velocity (Vs) structure, together with Moho depths have been estimated beneath the northwestern Himalaya, and adjoining regions by inverting fundamental mode Rayleigh wave group velocities calculated from regional earthquake (source-receiver distance ≤ 2500 km) data, and also from their joint inversions with teleseismic receiver functions at 38 of the 59 broadband stations in the region that provided the data. The results yield a detailed shear-wave velocity structure of northwestern Himalaya extending from Hindu Kush through Kohistan-Nanga Parbat to Kashmir Himalaya, as well as the Pamirs in the north and Lesser Himalaya along with the foreland basin including the Hazara syntaxis in the south. In particular, main results obtained are, a) presence of ubiquitous low-velocity layer (Vs ~3 km/s) at ~30 km depth beneath the NW Himalaya but apparently absent beneath the Kashmir Himalaya b) characterization of the western Tarim and Tadjik basins by low velocities up to ~20 km c) shallow (~10 km) high velocities beneath Pamir and Ladakh Himalaya d) distinctly shallower Moho beneath the Himalayan arc apparently segmented by arc-normal shear zones that cross the rupture zones of the 1905 Kangra and the 2005 Kashmir earthquakes and e) Lower Vs roots of the Pamirs at ~30 and 40 km.

Presenting Author: Ramees R. Mir

Student Presenter: No

Authors