Crustal structure beneath the central Tien Shan from ambient noise tomography

Through analysis of seismic ambient noise recorded by the GHENGIS array, we constructed a high-resolution 3-D crustal shear-wave velocity model for the central Tien Shan. The obtained shear-wave velocity model provides insight into the detailed crustal structure beneath the Tien Shan. The results obtained at shallow depths are well correlated with known subsurface geological features. Low velocities are found mainly beneath sedimentary basins, whereas high velocities are mainly associated with mountain ranges. At greater depths of similar to 43-45 km, high velocities were observed beneath the Tarim Basin and Kazakh Shield; these high velocities extend forward in opposite directions and tilt down towards the central Tien Shan to a depth of in excess of 50 km, most likely reflecting lateral variations in crustal thickness beneath the Tien Shan and surrounding platforms