Lithosphere structure of Yinchuan basin from a long-range seismic wide angle reflection and refraction profile

By using P-wave travel time data from three shots of the deep seismic sounding profiles passing through Yinchuan basin in 2014, based on travel time inversion method Rayinvr, we get the crustal and upper-mantle structure in the studied area. The results show that crustal thickness in the studied area varies from 42 km to 48 km, Moho depth is shallower in the east and west sides of the profile, and much deeper in the middle segment, the deepest Moho interface is beneath Helan mountain. P wave velocity increases with the increasing of depth in a positive gradient, but two distinct interfaces can be identified in the lithosphere mantle within the depths of 90-103 km. This layer does not exhibit the characteristic that the velocity increases obviously with the depth, suggesting the structure in the studied area present a characteristic that did not conform to the global average model, whose velocity increases according to the depth, therefore it is deduced that a velocity transition zone exists between lithosphere and asthenosphere beneath Yinchuan basin.