关键词: 地壳变形, GPS, 岩石圈, 各向异性

Abstract: Plate motion is one of the major dynamic sources for crustal and mantle deformation. As crustal deformation can be measured by GPS and geologic observation,the comparison between crustal deformation and mantle deformation is an effective approach to understanding the coupling relationship between the crustal movement and the mantle deformation. In this study,regional crustal strain rate tensors for China inferred from GPS measurements,slip rates of Quaternary active fault and earthquake deformation data within an area of approximately 200×200km²,are incorporated with smooth,continuous functions (sp line) to determine the self consistent model of present day velocity gradient tensor field for Chinas continent. In the incorporation process,GPS velocity vectors are also matched,within a defined frame of reference,with the model velocity field. The results are then compared with the anisotropy of the Pn wave and with the fast directions of shear-wave splitting inferred from the SKS phases,which may represent the shear deformation in the mantle and the deep crust,respectively. The comparison shows that there is relatively large difference between the average directions of crustal shearing and that of mantle shearing in the regions of active tectonics. This may indicate the decoupling of crustal movement and mantle deformation in these active regions.

Key words: crustal deformation, GPS, lithosphere anisotropy