Present-Day Crustal Deformation in China Constrained by Global Positioning System Measurements

Abstract

Global Positioning System (GPS) measurements in China indicate that crustal shortening accommodates most of India's penetration into Eurasia. Deformation within the Tibetan Plateau and its margins, the Himalaya, the Altyn Tagh, and the Qilian Shan, absorbs more than 90% of the relative motion between the Indian and Eurasian plates. Internal shortening of the Tibetan plateau itself accounts for more than one-third of the total convergence. However, the Tibetan plateau south of the Kunlun and Ganzi-Mani faults is moving eastward relative to both India and Eurasia. This movement is accommodated through rotation of material around the eastern Syntaxis. The North China and South China blocks, east of the Tibetan Plateau, move coherently east-southeastward at rates of 2 to 8 millimeters per year and 6 to 11 millimeters per year, respectively, with respect to the stable Eurasia.

Using shear wave splitting measurements to investigate the upper mantle anisotropy beneath the North China Craton: Distinct variation from east to west

“…Although the observations are obtained from different experiments, the values of f in the Central Zone show good consistency trending NE to NNE, except for stations GAN and XIT with E-W trending fast polarization direc- [Zhang, 1997], and the two big gray arrows indicate the extensional direction during Late Mesozoic to Early Cenozoic. The inset is a map with topography on which the APM direction [Wang et al, 2001] is marked as a dark arrow. Table 1 (auxiliary material) shows small standard deviation both in delay time and fast azimuths giving the impression of the data quality: f and dt variations do not exceed ±5°and ±0.15s, respectively.…”

“…The GPS measurements [Wang et al, 2001] show coherent movement of North China at rates of 2 to 8 mm/ year to the direction of N120°-N140°(marked as a big arrow in the inset of Figure 1). Whatever the reference frame taken, the slow plate motion is not expected to generate strong flow in the upper mantle and could hardly explain short-scale f variations of 90°within the region.…”

Crustal–lithospheric structure and continental extrusion of Tibet

“…Wang et al (2001) compiled local GPS networks occupied between 1991 and 2001 consisting of 354 stations and showed that 90% of the India-Asia relative motion (measured to be 38 mm a À1 ) is absorbed through deformation in Tibet and its margins. updated this dataset to include 533 stations on and around the plateau in which 36-40 mm a À1 India-Asia convergence was measured, with 15-20 mm a À1 N208E shortening across the Himalaya, 10-15 mm a À1 across the Tibetan Plateau interior, and 5-10 mm a À1 across the northern margin.…”

Extensional Seismogenic Stress and Tectonic Movement on the Central Region of the Tibetan Plateau

“…The rates of horizontal displacement lie in a general N-S direction on the western plateau and the western edge of the Kunlun Mountains. The eastward annually rates are between 15 and 20 mm/a in the central plateau [8]. The annually rates of displacements lie identically in a generally easterly direction on the eastern boundary of the Tibetan plateau, in the southern segment of the NSSB, almost same as those in the central plateau.…”

“…The compressive tectonic force affects crustal motions in the west of China and as far as Mongolia [5,6]. Such motion and deformation make the Tibetan plateau and its surrounding areas one of the most active regions in terms of tectonics and seismicity in the world [7,8]. The synchronous temporal variations of the seismic activities on the Tibetan plateau region and its vicinity are related to the compressional collision between the Indian and Eurasian plates [9,10].…”