Abstract
Pure path Rayleigh-wave group velocities for 24 regional grids inside the Arctic have been obtained from 74 mixed-path measurements. The vertical shear-wave velocity structures under these 24 grids were then determined according to their pure-path group-velocity dispersion data. This result indicates that the crustal shear-wave velocity in the Arctic region is generally lower than the worldwide average. In addition, a typical mid-ocean ridge structure was clearly shown under the Nansen Ridge. We also found an abnormally high upper mantle shear-wave velocity under the Alpha Ridge and Makarov Basin, and low velocity beneath the Canadian Arctic Islands. In general, our inversion result agrees with the known tectonics in the Arctic region. To further check the validity of our result, we have computed synthetic Rayleigh waves and a comparison with our observations shows very good agreement.
