Contemporary crustal movement of continental China obtained by global positioning system (GPS) measurements

Ma, Zongjin; Chen, Xinlian; Ye, Shuhua; Lai, Xi’an; Wei, Ziqing; Chen, Jun-Rong; Ning, Jinsheng; Xu, Huoze; Ding, Guoqiang

doi:10.1007/bf02900579

Cited by 25 publications

(10 citation statements)

References 12 publications

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“…The latter reflects that the plates are self-driven and decoupled from the mantle by a mechanically weak asthenosphere, and that the mantle deformation is attributed to the difference between the top and the bottom velocities in the asthenosphere. GPS measurements [46][47][48] (Figure 6) show the eastward and southwardtrending velocity field in the Ordos Block margins, which is consistent with the distribution of fast-wave directions. The consistency implies that the crustal and upper mantle deformation are also consistent.…”

Section: Analysis Of Crust-mantle Coupling and Decoupling In The Ordosupporting

confidence: 67%

Upper mantle anisotropy in the Ordos Block and its margins

Chang

Wang

Ding

2011

Sci. China Earth Sci.

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Based on the polarization analysis of teleseismic data, SKS (SKKS) fast-wave directions and delay times between fast and slow shear waves were determined for each of the 111 seismic stations from both permanent and temporary broadband seismograph networks deployed in the Ordos Block and its margins. Both the Silver and Chan and stacking analysis methods were used. In this way, an image of upper mantle anisotropy in the Ordos Block and its margins was acquired. In the western and northern margins of the Ordos Block, the fast-wave directions are consistently NW-SE. The fast-wave directions are mainly NWW-SEE and EW in the southern margin of the Ordos Block. In the eastern margin of the Ordos Block, the fast-wave directions are generally EW, although some run NEE-SWW or NWW-SEE. In the Ordos Block, the fast-wave directions trend near N-S in the north, but switch to near EW in the south. The delay time between fast and slow waves falls into the interval 0.48-1.50 s, and the average delay time at the stations in the Ordos Block is less than that in its margins. We suggest that the anisotropy of the stable Ordos Block is mainly caused by "fossil" anisotropy frozen in the ancient North China Craton. The NE-trending push of the northeastern margin of the Tibetan Plateau has caused NW-SE-trending lithospheric extension in the western and northern margins of the Ordos Block, and made the upper mantle flow southeastwards. This in turn has resulted in the alignment of the upper mantle peridotite lattice with the direction of material deformation. In the southern margin of the Ordos Block, the collision between the North China and Yangtze blocks resulted in the fast-wave direction running parallel to the collision boundary and the Qinling Orogen. Combining this with the APM and velocity structure of the Qinling Orogen, we propose that eastward-directed asthenospheric-mantle channel flow may have occurred beneath the Qinling Orogen. In the eastern margin of the Ordos Block, the complex anisotropic characteristics of the Fenhe Graben and Taihang Orogen may be caused by the interaction of western Pacific Plate subduction, regional extensional tectonics, and the orogeny. For station YCI, the apparent splitting parameters (the fast-wave directions range from 45° to 106° and the delay times range from 0.6 to 1.5 s) exhibit systematic variations as a function of incoming polarization with a periodicity of /2. This variation can be best explained by a two-layer anisotropic model ( lower = 132°, t lower = 0.8 s,  upper = 83°, t upper = 0.5 s). The upper layer anisotropy beneath station YCI can again be attributed to "fossil" anisotropy frozen in the ancient North China Craton. The lower layer anisotropy is affected by the tectonic activity of the western Ordos Block. The NW-SE trending extension caused by the NE trending push of the northeastern margin of the Tibetan Plateau affected the deformation of the lower anisotropic layer beneath station YCI. By comparing the fast-wave directions with GPS velocity directions, we see that ...

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Section: Analysis Of Crust-mantle Coupling and Decoupling In The Ordosupporting

confidence: 67%

Upper mantle anisotropy in the Ordos Block and its margins

Chang

Wang

Ding

2011

Sci. China Earth Sci.

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“…Due to the northward compression of India Plate on the southwest of China, the northward and westward subduction of the Pacific and Philippine Sea Plates on the east, and the obstruction of Siberian platform on the north, Chinese mainland shows the characteristics of compression in the west and extension in the east, and the continental material is eastward and southward extruded [19,20] . The GPS measurements [36][37][38] show the eastward and southward-trending velocity field, which is consistent with the fast-wave direction. The consistency implies that the crustal deformation and the upper mantle deformation are consistent.…”

Section: Causes Of Anisotropysupporting

confidence: 67%

Seismic anisotropy of upper mantle in eastern China

Chang

Wang

Ding

2009

Sci. China Ser. D-Earth Sci.

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Based on the polarization analysis of teleseismic SKS waveform data recorded at 65 seismic stations which respectively involved in the permanent and temporary broadband seismograph networks deployed in eastern China, the SKS fast-wave direction and the delay time between the fast and slow shear waves at each station were determined by use of SC method and the stacking analysis method, and then the image of upper mantle anisotropy in eastern China was acquired. In the study region, from south to north, the fast-wave polarization directions are basically EW in South China, gradually clockwise rotate to NWW-SEE in North China, then to NW-SE in Northeast China. The delay time falls into the interval [0.41 s, 1.52 s]. Anisotropic characteristics in eastern China indicate that the upper mantle anisotropy is possibly caused by both the collision between the Indian and Eurasian Plates and the subduction from the Pacific and Philippine Sea Plates to the Eurasian Plate. The collision between two plates made the crust of western China thickening and uplifting and the material eastwards extruding, and then caused the upper mantle flow eastwards and southeastwards. The subduction of Pacific Plate and Philippine Sea Plate has resulted in the lithosphere and the asthenosphere deformation in eastern China, and made the alignment of upper mantle peridotite lattice parallel to the deformation direction. The fast-wave polarization direction is consistent with the direction of lithosphere extension and the GPS velocity direction, implying that the crust-upper mantle deformation is possibly a vertically coherent deformation. eastern China, upper mantle anisotropy, SKS wave, fast-wave direction, lithosphere deformationSeismic anisotropy is an effective method for understanding the crust and upper mantle deformation. The anisotropy can be used to understand the intraplate deformation features and the deformation status of lithosphere mantle related to the plate tectonic movements. Recent researches show that the mantle anisotropy is a consequence of strain-induced lattice preferred orientation of olivine crystals [1,2] . There are several causes resulting in the mantle deformation. Among them, the plate motion is a direct cause. The size and direction of the mantle anisotropy strongly depend on the velocity of the plate motion. Based on the assumption of plate driving force, two kinematics models of crust-mantle deformation have been proposed recently, i.e., the vertically coherent deformation [3,4] and the simple asthenospheric flow [5] . The former predicts that the plates strongly have been coupled with the mantle and driven by the flow field generated from density heterogeneity in the mantle. The latter reflects that the plates are self-driven and decoupled from the mantle by mechanically weak asthenosphere, and the mantle deformation is attributed to the difference between the top and the bottom velocities in asthenosphere. In the various subjects of recent studies on geodynamics, the mantle anisotropy is one of the effective mea...

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“…Since the early 20 th century, many geodetic strategies, including trigonometrical surveys, arc measurements, leveling surveys, GPS measurements and gravity measurements, have been carried out by numerous international research institutes in order to gain knowledge of the present-day crustal deformation and movement status. The geodetic measurements have resulted in abundant information and basic data for studies on the mechanisms of the tectonic deformation in the plateau and led to some significant results (Ma et al 2001;Wang et al 2001Wang et al , 2004Xu 2001;Zhang et al 2002;Sun et al 2009). Lhasa is located on the southern part of the Tibetan Plateau, on the northern side of the Himalayan Mountains and on flat land in a valley in the middle reaches of the Lhasa River, a tributary of the Brahmaputra.…”

Section: Introductionmentioning

confidence: 99%

Results of Gravity Observations Using a Superconducting Gravimeter at the Tibetan Plateau

Sun¹,

Xu²,

Chen³

et al. 2013

Terr. Atmos. Ocean. Sci.

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The tidal and nontidal gravity change characteristics in the Tibetan Plateau region were investigated using the continuous gravity measurements recorded with a superconducting gravimeter (SG) installed in Lhasa from December 8, 2009 to September 30, 2011. The results indicated that the precision of the tidal gravity observations with the SG in Lhasa was very high. The standard deviation of the harmonic analysis for the gravity tides was 0.498 nm s -2 , and the uncertainties of amplitude factors in the four main tidal waves (i.e., O 1 , K 1 , M 2 and S 2 ) were better than 0.002%. In addition, the diurnal gravity tide observations clearly revealed a pattern of nearly diurnal resonance. As a result, it is affirmed that the station should act as a local tidal gravity reference in the Tibetan Plateau and its adjacent regions. The load effects of oceanic tides are so weak that the resulting perturbation in the gravimetric factors is less than 0.6%. However, the load effects of the local atmosphere on either the tidal or the nontidal gravity observations are significant, although no seasonal variations have been found. After removing the atmospheric effects, the standard deviation of the harmonic analysis for the gravity tides decreased obviously from 4.160 to 0.498 nm s -2 . Having removed the load effects of oceanic tides and local atmosphere, it is found that the tidal gravity observations are significantly different from those expected theoretically, which may be related to active tectonic movement and extremely thick crust in the Tibetan Plateau region. In addition, the Earth's free oscillations excited by 2011 Tohoku-Oki M w 9.0 Earthquake were successfully detected.

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Contemporary crustal movement of continental China obtained by global positioning system (GPS) measurements

Cited by 25 publications

References 12 publications

Upper mantle anisotropy in the Ordos Block and its margins

Upper mantle anisotropy in the Ordos Block and its margins

Seismic anisotropy of upper mantle in eastern China

Results of Gravity Observations Using a Superconducting Gravimeter at the Tibetan Plateau

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