GPS measurements of crustal deformation in the Baikal rift zone

Calais, E., O. Lesne, J. Deverchère, V. Sankov, A. Lukhnev, A. Miroshnitchenko, V. Buddo, K. Levi, V. Zalutzky, and Y. Bashkuev, GPS measurements of crustal deformation in the Baikal rift zone, Siberia, Geophys. Res. Letters, 25, 4003-4006, 1998.


The Baikal rift zone, located at the northern edge of the central Asia intracontinental deformation zone, is the largest active continental rift system in Eurasia. It extends over a distance of about 2000 km along the S-shaped paleozoic suture that separates the Siberian Platform from the Sayan-Baikal mobile belt. GPS measurements in the Baikal rift zone were initiated in July 1994 with the installation and first observation of a network of 11 sites covering its southern and western parts. Three years and four campaigns of Global Positioning System (GPS) measurements (1994-1997) in the Baikal rift zone, largest active continental rift system in Eurasia, show crustal extension at a rate of 4.5±1.2 mm/yr in a WNW-ESE direction. A comparison with moment release of large historical earthquakes suggests that elastic strain is currently accumulating in the Baikal rift zone along active faults that currently have the potential for a M=7.5 earthquake. The GPS-derived extension rate in the Baikal rift zone is at least two times greater than the prediction of most deformation models of Asia. This result could reflect the dynamic contribution of the Pacific-Eurasia subduction to intracontinental deformation in Asia, in addition to the effect of the India-Eurasia collision.