Shear wave velocity structure of the upper-mantle beneath the northern Zagros collision zone revealed by nonlinear teleseismic tomography and Bayesian Monte-Carlo joint inversion of surface wave dispersion and teleseismic P-wave coda

摘要: Abstract The continental collision between the Arabian and Eurasian plates plays an important role in geodynamical evolution of Zagros Iranian plateau. In order to investigate upper mantle structure across zone, we calculated absolute relative shear-wave velocity along a dense long temporary seismic profile NW Iran. probabilistic 1-D (Vs) depth profiles beneath 23 stations were using trans-dimensional joint inversion approach P-wave coda together with Rayleigh wave phase group dispersion data. These models are then interpolated obtain 2-D Vs model profile. addition, used nonlinear teleseismic tomography method determine shear variations 44 stations. Both models, obtained by different data sets methods, show thick (>150 km) high-velocity anomaly northern part Zagros, which could be thickened lithosphere associated shortening. A relatively thin (~80 km) lower S-wave Central Iran may suggest weakened upwelling hot asthenosphere following slab break-off. presence implies that Arabian-Eurasian convergence is accommodated mainly as shortening rather than underthrusting narrow low-velocity corridor overriding plate (Central Iran), south Sanandaj-Sirjan Zone (SSZ), probably due delamination subducting from crust, likely prohibits transferring stress Iran, causing less deformation SSZ edge plate.