Monitoring Crustal Movement in the Qinghai-Tibetan Plateau Using GPS Measurements from 1993 to 2002

Abstract

AbstractThe Tibetan Plateau is the center-piece of the broad India-Eurasia collision zone, and a natural laboratory to study large-scale continental deformation. We analyze Tibet campaign data from 1993 to 2002 and some continuous Global Positioning System (GPS) stations around Tibet using GAMIT/GLOBK software. The data analysis involves two major procedures. The first procedure uses the GAMIT software to estimate parameters such as station position and orbital trajectory on a daily basis from the union of two data sets: (a) the campaign stations, and (b) long-running continuous GPS stations around Tibet. In the second procedure, we combine the daily solutions with global GPS sub-networks (IGS1, IGS2, IGS3), which are provided by Scripps Institute of Oceanography (SIO), using the GLOBK software in a “regional stabilization” approach in order to estimate the positions and velocities. Then we discuss present-day crustal movement of Qinghai-Tibetan Plateau, and determine the strain rate. The conclusion is that the Himalayan block is mainly under compressing strain, and the maximum compressing rate is -98.5 ± 4.2 nstrain/yr and with the extension rate of 26.7 ± 2.8 nstrain/yr in the direction of N127.1 ± 0.7°E; the middle part of the Tibet block is mainly under compressing strain, and the maximum compressing rate is -20.3 ± 1.2 nstrain/yr in the direction of N39.0 ± 2.0°E with the extension rate of 10.8 ± 1.6 nstrain/yr in the direction of N129 ± 2.0°E. Both principal compressing strain rate and extension rate trails off from the Himalayan block to the middle part of the Tibet block. Besides, GPS result shows that Tibet Plateau uplifts with 3–5 mm per yearKeywordsGPSTibetDeformationstrain rate