scholarly journals Crustal Deformation on the Northeastern Margin of the Tibetan Plateau from Continuous GPS Observations

2018 ◽  
Vol 11 (1) ◽  
pp. 34 ◽  
Author(s):  
Xiaoning Su ◽  
Lianbi Yao ◽  
Weiwei Wu ◽  
Guojie Meng ◽  
Lina Su ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Crustal Deformation ◽  
Flicker Noise ◽  
Noise Model ◽  
Tectonic Deformation ◽  
Deformation Pattern ◽  
The Tibetan Plateau ◽  
Strain Rates ◽  
Strain Accumulation ◽  
Strain Partitioning

We installed 10 continuous Global Positioning System (GPS) stations on the northeast margin of the Tibetan Plateau at the end of 2012, in order to qualitatively investigate strain accumulation across the Liupanshan Fault (LPSF). We integrated our newly built stations with 48 other existing GPS stations to provide new insights into three-dimensional tectonic deformation. We employed white plus flicker noise model as a statistical model to obtain realistic velocities and corresponding uncertainties in the ITRF2014 and Ordos-fixed reference frame. The total velocity decrease from northwest to southeast in the Longxi Block (LXB) was 5.3 mm/yr within the range of 200 km west of the LPSF on the horizontal component. The first-order characteristic of the vertical crustal deformation was uplift for the northeastern margin of the Tibetan Plateau. The uplift rates in the LXB and the Ordos Block (ORB) were 1.0 and 2.0 mm/yr, respectively. We adopted an improved spherical wavelet algorithm to invert for multiscale strain rates and rotation rates. Multiscale strain rates showed a complex crustal deformation pattern. A significant clockwise rotation of about 30 nradians/yr (10−9 radians/year) was identified around the Dingxi. Localized strain accumulation was determined around the intersectional region between the Haiyuan Fault (HYF) and the LPSF. The deformation pattern across the LFPS was similar to that of the Longmengshan Fault (LMSF) before the 2008 Wenchuan MS 8.0 earthquake. Furthermore, according to the distributed second invariant of strain rates at different spatial scale, strain partitioning has already spatially localized along the Xiaokou–Liupanshan–Longxian–Baoji fault belt (XLLBF). The tectonic deformation and localized strain buildup together with seismicity imply a high probability for a potential earthquake in this zone.

scholarly journals Crustal Deformation Prior to the 2017 Jiuzhaigou, Northeastern Tibetan Plateau (China), Ms 7.0 Earthquake Derived from GPS Observations

2018 ◽  
Vol 10 (12) ◽  
pp. 2028 ◽  
Author(s):  
Weiwei Wu ◽  
Xiaoning Su ◽  
Guojie Meng ◽  
Chentao Li
Keyword(s):  
Tibetan Plateau ◽  
Strain Rate ◽  
Crustal Deformation ◽  
Multiscale Approach ◽  
Deformation Pattern ◽  
Strain Rate Tensor ◽  
Strain Rates ◽  
Shear Strain Rate ◽  
Jiuzhaigou Earthquake ◽  
Epicentral Area

The 2017 Jiuzhaigou Ms 7.0 earthquake occurred on the northeastern margin of the Tibetan Plateau, with no noticeable rupture surface recognized. We characterized the pre-seismic deformation of the earthquake from GPS (Global Positioning System) data at eight continuous and 73 campaign sites acquired over the 2009–2017 period. With respect to the Eurasian plate, the velocity field showed a noticeable decrease, from west of the epicenter of the Jiuzhaigou earthquake to the western edge of the Longmenshan fault, in the southeast direction. The total northwest west–southeast east shortening rate in the vicinity of the epicentral area was in the range of 1.5 mm/y to 3.1 mm/y. With a GPS velocity transect across the Huya fault (HYF), where the epicenter was located, we estimated the activity of the HYF, showing a dominant left-lateral slip rate of 3.3 ± 0.2 mm/y. We calculated strain rates using a spherical wavelet-based multiscale approach that solved for the surface GPS velocity according to multiscale wavelet basis functions while accounting for spatially variable spacing of observations. Multiscale components of the two-dimensional strain rate tensor showed a complex crustal deformation pattern. Our estimates of strain rate components at the scale of seven and eight revealed extensional strain rate on the northern extension of the HYF. The Jiuzhaigou earthquake occurred at the buffer zone between extensional and compressional deformation, and with significant maximum shear rates being 100–140 nanostrain/y. In addition, a maximum shear strain rate of 60–120 nanostrain/y appeared around the epicenter of the 2013 Ms 6.6 Minxian–Zhangxian earthquake. These findings imply that inherent multiscale strain rates could be separated to identify strain accumulation related to medium- and large-sized earthquakes.

scholarly journals Present-day strain accumulation in the Liupan Shan area, northeastern margin of the Tibetan Plateau by GPS observations

2019 ◽  
Vol 30 (1) ◽  
pp. 51-62
Author(s):  
Guojie Meng ◽  
Xiaoning Su ◽  
Wanzhen Xu ◽  
Chieh-Hung Chen ◽  
Kai-Chien Cheng ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
The Tibetan Plateau ◽  
Strain Accumulation ◽  
Gps Observations ◽  
Liupan Shan

Tectonic Deformation and Surface Processes of the Tibetan Plateau Constrained by Time Series Analysis of Sentinel-1 InSAR Data

2020 ◽  
Author(s):  
Robert Zinke ◽  
Gilles Peltzer ◽  
Eric Fielding ◽  
Simran Sangha ◽  
David Bekaert ◽  
...  
Keyword(s):  
Time Series ◽  
Tibetan Plateau ◽  
Surface Deformation ◽  
Active Faults ◽  
High Rate ◽  
Surface Processes ◽  
Tectonic Deformation ◽  
The Tibetan Plateau ◽  
Data Set ◽  
Temporal Sampling

<p>We quantify deformation patterns resulting from tectonic motions and surface processes across the central Tibetan Plateau (29–45ºN, 83–92ºE) since late 2014 using ascending and descending passes of the Sentinel-1A and -1B radar satellites. The broad spatial extent of these data (> 10<sup>6</sup> km<sup>2</sup>), fine spatial resolution (originally 90 m pixels, resampled to 270 m pixels), and high rate of temporal sampling (12–24-day orbit repeat time) offer unprecedented resolution of surface deformation in space and time. To process such an extensive data set – including more than 100 dates and 300 interferograms per track thus far – we leverage the Advanced Rapid Imaging and Analysis (ARIA) standardized interferometric synthetic aperture radar (InSAR) products and toolbox. We construct time series of surface deformation constrained from our Sentinel-1 interferograms using the small baseline subset approach implemented by the Miami InSAR time series software in Python (MintPy). Our preliminary results from three Sentinel-1 orbits (two descending and one ascending; each comprising 10 frames along track) allow us to quantify deformation in the satellite lines of sight. Combinations of ascending and descending track measurements are used to approximate east-west and vertical ground velocities. The resulting velocity fields will provide a more complete and accurate picture of interseismic strain accumulation rates across active faults in the region such as the Altyn Tagh and Kunlun faults, and allow us to study surface processes such as permafrost active layer dynamics and isostatic adjustment due to lake level changes in unparalleled scope and detail.</p>

scholarly journals Large-scale crustal deformation of the Tibetan Plateau

2001 ◽  
Vol 106 (B4) ◽  
pp. 6793-6816 ◽  
Author(s):  
Feng Shen ◽  
Leigh H. Royden ◽  
B. Clark Burchfiel
Keyword(s):  
Tibetan Plateau ◽  
Crustal Deformation ◽  
Large Scale ◽  
The Tibetan Plateau

scholarly journals Mesozoic–Cenozoic Uplift/Exhumation History of the Qilian Shan, NE Tibetan Plateau: Constraints From Low-Temperature Thermochronology

2021 ◽  
Vol 9 ◽  
Author(s):  
Lihao Chen ◽  
Chunhui Song ◽  
Yadong Wang ◽  
Xiaomin Fang ◽  
Yihu Zhang ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Low Temperature ◽  
Tectonic Deformation ◽  
Mountain Range ◽  
The Tibetan Plateau ◽  
Two Phase ◽  
Late Mesozoic ◽  
Plate Convergence ◽  
History Of ◽  
Upward Growth

The Qilian Shan, which is located along the northeastern margin of the Tibetan Plateau, plays a key role in understanding the dynamics of the outward and upward growth of the plateau. However, when and how tectonic deformation evolved into the geographic pattern which is currently observed in the Qilian Shan are still ambiguous. Here, apatite fission track (AFT) thermochronology and sedimentology were conducted to interpret the low-temperature tectonic deformation/exhumation events in well-dated Late Miocene synorogenic sediment sequences in the Xining Basin, which is adjacent to the southern flank of the Qilian Shan. These new low-temperature thermochronological results suggest that the Qilian Shan experienced four stages of tectonic exhumation during the late Mesozoic–Cenozoic. The Late Cretaceous exhumation events in the Qilian Shan were caused by the diachronous Mesozoic convergence of the Asian Plate and Lhasa Block. In the early Cenozoic (ca. 68–48 Ma), the Qilian Shan quasi-synchronously responded to the Indian–Asian plate collision. Subsequently, the mountain range experienced a two-phase deformation during the Eocene–Early Miocene due to the distal effects of ongoing India–Asia plate convergence. At ca. 8 ± 1 Ma, the Qilian Shan underwent dramatic geomorphological deformation, which marked a change in subsidence along the northeastern margin of the Tibetan Plateau at that time. Our findings suggest that the paleogeographic pattern in the northeastern Tibetan Plateau was affected by the pervasive suture zones in the entire Qilian Shan, in which the pre-Cenozoic and Indian–Asian plate motions reactivated the transpressional faults which strongly modulated the multiperiodic tectonic deformation in northern Tibet during the Cenozoic. These observations provide new evidence for understanding the dynamic mechanisms of the uplift and expansion of the Tibetan Plateau.

Late Mesozoic−Cenozoic cooling history of the northeastern Tibetan Plateau and its foreland derived from low-temperature thermochronology

2021 ◽  
Author(s):  
Chen Wu ◽  
Andrew V. Zuza ◽  
Jie Li ◽  
Peter J. Haproff ◽  
An Yin ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Low Temperature ◽  
Large Scale ◽  
Qaidam Basin ◽  
Tectonic Deformation ◽  
Formation Mechanisms ◽  
The Tibetan Plateau ◽  
Thrust Belt ◽  
The South ◽  
Late Mesozoic

The growth history and formation mechanisms of the Cenozoic Tibetan Plateau are the subject of an intense debate with important implications for understanding the kinematics and dynamics of large-scale intracontinental deformation. Better constraints on the uplift and deformation history across the northern plateau are necessary to address how the Tibetan Plateau was constructed. To this end, we present updated field observations coupled with low-temperature thermochronology from the Qaidam basin in the south to the Qilian Shan foreland in the north. Our results show that the region experienced a late Mesozoic cooling event that is interpreted as a result of tectonic deformation prior to the India-Asia collision. Our results also reveal the onset of renewed cooling in the Eocene in the Qilian Shan region along the northern margin of the Tibetan Plateau, which we interpret to indicate the timing of initial thrusting and plateau formation along the plateau margin. The interpreted Eocene thrusting in the Qilian Shan predates Cenozoic thrust belts to the south (e.g., the Eastern Kunlun Range), which supports out-of-sequence rather than northward-migrating thrust belt development. The early Cenozoic deformation exploited the south-dipping early Paleozoic Qilian suture zone as indicated by our field mapping and the existing geophysical data. In the Miocene, strike-slip faulting was initiated along segments of the older Paleozoic suture zones in northern Tibet, which led to the development of the Kunlun and Haiyuan left-slip transpressional systems. Late Miocene deformation and uplift of the Hexi corridor and Longshou Shan directly north of the Qilian Shan thrust belt represent the most recent phase of outward plateau growth.

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