[1] Using the measurements of 750 GPS stations around the Tibetan Plateau for over 10 years since 1999, we derived a high-resolution 3-D velocity field for the present-day crustal movement of the plateau. The horizontal velocity field relative to stable Eurasia displays in details the crustal movement and tectonic deformation features of the India-Eurasia continental collision zone with thrust compression, lateral extrusion, and clockwise rotation. The vertical velocity field reveals that the Tibetan Plateau is continuing to rise as a whole relative to its stable north neighbor. However, in some subregions, uplift is insignificant or even negative. The main features of the vertical crustal deformation of the plateau are the following: (a) The Himalayan range is still rising at a rate of~2 mm/yr. The uplift rate is 6 mm/yr with respect to the south foot of the Himalayan range. (b) The middle eastern plateau has a typical uplift rate between 1 and 2 mm/yr, and some high mountain ranges in this area, like the Longmen Shan and Gongga Shan, have surprising uplift rates as large as 2-3mm/yr. (c) In the middle southern plateau, there is a basin and endorheic subregion with a series of NS striking normal faults, showing obvious sinking with the rates between 0 and -3 mm/yr. (d) The present-day rising and sinking subregions generally correspond well to the Cenozoic orogenic belts and basins, respectively. (e) At the southeastern corner of the plateau. There is an apparent trend that the uplift rate is gradually decreasing from between 0.8 and 2.3 mm/yr in the inner plateau to between -0.5 and -1.6 mm/yr outside the plateau, with the decrease of terrain height.Citation: Liang, S., W. Gan, C. Shen, G. Xiao, J. Liu, W. Chen, X. Ding, and D. Zhou (2013), Three-dimensional velocity field of present-day crustal motion of the Tibetan Plateau derived from GPS measurements,

Eastward transport and clockwise rotation of crust around the southeastern margin of the Tibetan Plateau dominates active deformation east of the Eastern Himalayan Syntaxis. Current crustal movement inferred from GPS measurements indicates ongoing distortion of the traces of the active Red River fault and the Mesozoic Yalong-Yulong-Longmen Shan thrust belt. By extrapolating current rates back in time, we infer that this pattern of deformation developed since 10.1 ± 1.5 Ma. This date of initiation is approximately synchronous with a suite of tectonic phenomena, both near and far, within the wide Eurasia/Indian collision zone, including the initiation of slip on the Ganzi-Yushu-Xianshuihe fault and crustal thinning and E-W extension by normal faulting on N-S−trending rifts in the plateau interior. Accordingly, the eastward movement of eastern Tibet and the clockwise rotation of that material seem to be local manifestations of a larger geodynamic event at ca. 10−15 Ma that changed the kinematic style and reorganized deformation not only on the plateau-wide scale, but across the entire region affected by the India/Eurasia collision. Convective removal of some or all of Tibet’s mantle lithosphere seems to offer the simplest mechanism for these approximately simultaneous changes.

We have delineated ten years of urban subsidence derived from continuous GPS stations operated by the Crustal Movement Observational Network of China (CMONOC) within and adjacent to the municipality of Tianjin. A method for obtaining accurate site velocities with respect to a stable regional reference frame is described. CMONOC stations in Jizhou (JIXN) and Baodi (TJBD) districts recorded minor subsidence of approximately 1 to 2 mm yr −1 during the period from 2010 to 2019. One station in Wuqing (TJWQ) district and one station in Binhai (TJBH) district recorded steady subsidence of approximately 5 and 2 cm yr −1 from 2010 to 2019, respectively. One station in Cangzhou (HECX) of Hebei Province, adjacent to Tianjin, recorded steady subsidence of approximately 2.4 cm yr −1 during 2010-2014 and more rapid subsidence of 4 cm yr −1 since 2015. TJWQ recorded the most rapid land subsidence and the most significant seasonal ground oscillations (uplift and subsidence) among these five stations. This study indicates that subsidence rates in Tianjin vary significantly in space and time. Particular attention should be paid, therefore, to extrapolate or infer a rate of subsidence for an area on the basis of a subsidence rate obtained from previous GPS observations or proximal GPS sites. The subsidence time series presented in this study provide reliable "ground truth" and constraints for calibrating or validating subsidence estimations from numerical modeling and repeated surveys using other remote sensing techniques, such as Interferometric Synthetic Aperture Radar (InSAR).

Based on high-rate (1 Hz) GPS data from the Sichuan GPS Continuous Observation Network on the footwall of the Longmenshan Fault, we have characterized the near-field surface movement process during the 5.12 Wenchuan Earthquake. Results show that the maximum deformation near the fault is larger than the deformation set. Stations on the northern segment of the fault moved towards the epicenter first, and then turned toward the vertical orientation of the fault. Deformation of stations on the southern segment is smaller and recovered. The initial motion at all of the stations was downward followed by periodic up and down movements. Comparing the displacement from high-rate GPS and accelerograph data, we can see that they are consistent prior to the arrival of the principal shock, but afterwards a 10 cm difference is found, even though they are synchronized and in phase. More work is yet to be done to explain this. This is the first time that actual the real near-field surface movements of an earthquake of M >7.0 have been determined in china. These measurements are therefore of high value for studies of surface rupture processes and the analysis of seismic wave travels paths in this region.high-rate GPS, the Wenchuan Earthquake, time of earthquake, near-field, surface movement process Citation:Yin H T, Zhang P Z, Gan W J, et al. Near-field surface movement during the Wenchuan M s 8.0 earthquake measured by high-rate GPS.

The 2021 Ms 6.4 Yangbi earthquake, Yunnan, China, was recorded by the Dali Global Positioning System (GPS) network comprising 37 permanent stations within 100 km of the epicenter. All of these GPS stations recorded 1 Hz data, and 12 of them also recorded 5 Hz data. Using sophisticated data processing strategies, especially the method to overcome ionospheric and multipath errors, near-field waveforms of epoch-by-epoch displacement of all of the GPS stations within an epicentral distance of ∼50 km were derived from high-rate GPS observations with a root mean square error of 3.8, 4.2, and 8.2 mm for the east–west, north–south, and up components, respectively. The peak ground displacement of up to 14 cm in the horizontal direction and 4.2 cm in the vertical direction and the largest coseismic displacement of 3.1 cm in the horizontal direction and 3.2 cm in the vertical direction were observed for the stations within 6–9 km of the epicenter. The waveforms, with dominant periods between 7 and 10 s, present a systematic change in shape as a function of distance from the source, which demonstrates that the high-rate GPS observations can provide reliable relative-displacement response spectra at the periods needed in the design of large structures for resisting strong earthquakes. Comparisons of the GPS displacement time series at 1, 2.5, and 5 Hz suggest that 5 Hz data are able to capture strong ground information that are of interest to both earthquake seismologists and engineers. We conclude that the displacement waveforms and motion trajectories from high-rate GPS observations provide unique additional information of the near-field strong ground motion that is valuable to seismologists in unraveling the dynamic process of fault rupture and to engineers for designing large structures with very long period response.