GPS measurements of crustal deformation in the Baikal-Mongolia
area (1994-2002): Implications for current kinematics of Asia

Calais, E., M. Vergnolle, V. Sankov, A. Lukhnev, A. Miroshnitchenko, S. Amarjargal, and J. Deverchere, GPS measurements of crustal deformation in the Baikal-Mongolia area (1994-2002): Implications for current kinematics of Asia, J. Geophys. Res., Vol. 108, No. B10, 2501, doi:10.1029/ 2002JB002373, 2003.


We present new geodetic results of crustal velocities over a large part of northern Asia based on GPS measurements in the Baikal rift zone and Mongolia spanning the 1994-2002 period. We combine our results with the GPS velocity field for China of Wang et al. (2001) and derive a consistent velocity field for most of Asia. We find contrasted kinematic and strain regimes in Mongolia, with northward velocities and NS shortening in westernmost Mongolia but east- to southeastward motion and left-lateral shear for central and eastern Mongolia. This east- to southeastward motion of central and eastern Mongolia is accommodated by left-lateral slip on the E-W trending Tunka, Bolnay, and Gobi Altay faults (2+-1.2 mm/yr, 2.6+-1.0 mm/yr, and 1.2 mm/yr, respectively) and by about 4 mm/yr of extension across the Baikal rift zone. Consequently, ~15% of the India-Eurasia convergence is accommodated north of the Tien Shan, by NS shortening combined with dextral shear in the Mongolian Altay, by eastward displacements along major left-lateral strike-slip faults in central and eastern Mongolia. We find a counter-clockwise rotation of North and South China as a quasi-rigid block around a pole north of the Stanovoy belt, which rules out the existence of an Amurian plate as previously defined and implies less than 2 mm/yr of left-lateral slip on the Qinling Shan fault zone.

GPS-derived velocities with respect to Eurasia. Ellipses are 95% confidence. Numbers by the site names are velocities with respect to Eurasia in mm/yr.
GPS-derived velocities with respect to Eurasia. Black arrows: our solution; White arrows: Wang et al.'s (2001) solution after transformation into ITRF2000 and rotation into a Eurasia-fixed frame (explanation in text). Ellipses are 95% confidence.