Seismic Imaging of Crust Beneath the Western Tibet‐Pamir and Western Himalaya Using Ambient Noise and Earthquake Data

We present a new high-resolution image of the crust beneath western Himalaya-Asia convergence zone encompassing geographical domain Himalaya-western Tibet-Ladakh-Karakoram-Pamir-Hindu Kush, using ambient noise cross-correlations from 530 seismological stations along with surface wave observations 1,261 earthquakes recorded over network. The 3-D shear velocity is created 22,726 inter-station Rayleigh dispersion measurements 5 to 60 s period at horizontal resolution less than 0.5° × following Bayesian Trans-dimensional Tree tomography approach. Moho Himalayas and south Tibet correlates transition 4.4–4.6 km/s reduced 4.0–4.2 in northern Pamir. used depth nature high-velocity lower (Vs > 4.0 km/s) map limit Indian that extends beyond Qiangtang block (77–82°E) its previously assumed boundary Lhasa till central Pamir farther west. reveals discontinuous low-velocity zones (LVZs; Vs < 3.4 mid-crust do not support existence channel flow model. LVZs correlate distribution gneiss domes. lowest velocities 3.2 are observed Ladakh-Karakoram batholith Nanga Parbat region. study suggests continuation across Karakoram Fault below 20 km, indicating fault's upper crustal extent.