New Constraints for the On‐Shore Makran Subduction Zone Crustal Structure

The Makran Subduction Zone is the primary seismic/tsunami hazard of northwestern Indian Ocean, but little known its on-shore seismic structure. We derived a shear wave velocity model extending to 100 km depth beneath ∼400 km-long profile oriented parallel convergence vector Arabian Sea Plate. Receiver function/surface analysis shows that average structure in coastal region comprises ∼22–28 km-thick low wavespeed sedimentary cover and 6–8 gradient zone overlying high upper mantle. ocean-basement interface dips gently northward, remaining positive impedance contrast ∼50 at ∼250 north coast where it disappears as basaltic/gabbroic oceanic crust has probably transformed eclogite. Further north, weak arrival ∼5 s receiver functions appears, grading northward into Moho continental Iranian Plateau. This disruption signature occurs forearc dip subducting plate steepens. southern Plateau's an Vs 3.55 ± 0.05 s−1, almost flat 40–45 deep, sub-Moho mantle 3.75 s−1 50–80 range. Weak conversions result from ∼20% serpentinization peridotite wedge. indicate – no crustal root topography volcanic belt, which therefore must be compensated by densities. Vp/Vs ratio observed for wedge suggests ∼1%–2% partial melt.