Contemporary crustal deformation in east Asia constrained by Global Positioning System measurements

Abstract

Global Positioning System (GPS) measurements collected since the early 90's allow us to derive geodetic velocities at 16 permanent stations in east Asia and 68 campaign mode sites in north China. The resulting velocity field shows the following: (1) Contrary to the early inferences that the Shanxi Rift has accommodated significant right‐slip motion, our results suggest that the rift system, at least in its northern part in north China, is under ESE‐WNW extension at a rate of 4±2 mm/yr. The velocity field also suggests that an ESE‐WNW trending left‐lateral shear zone deforming at a rate of 2±1 mm/yr may exist along the north rim of north China at the latitude of ∼40°N, separating actively extending north China in the south from relatively stable Mongolia in the north. (2) Central and east China move at a rate of 8–11 mm/yr east‐southeast with respect to Siberia, implying that the overall east‐southeastward motion is the dominant mode of deformation in east China. (3) The India plate moves at a rate of 6±1 mm/yr slower than the NUVEL‐1A model prediction relative to the Eurasia plate. (4) Significant eastward motion (20±2 mm/yr) with respect to Siberia occurs in southeastern Tibet. About half of this eastward motion (∼11 mm/yr) is absorbed by structures along the eastern boundary of the Tibetan Plateau.