Kinematics and strain rates of the Eastern Himalayan Syntaxis from new GPS campaigns in Northeast India

Gupta, Tanay Dutta; Riguzzi, Federica; Dasgupta, Sujit; Mukhopadhyay, Basab; Roy, Sujit; Sharma, S. B.

doi:10.1016/j.tecto.2015.04.017

Cited by 64 publications

(30 citation statements)

References 52 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The dominant orientations of fast polarizations in the subzone C are always positive, larger than 0°. The dominant orientations show a clockwise change with tendency of NNW to NS to NNE directions from the west to the east, which is consistent with surface strain and local principal compressive stress results obtained from GPS data (Zhang et al 2004;Gupta et al 2015;Jin et al 2019).…”

Section: Fast Polarizationsupporting

confidence: 88%

“…It suggests that seismic anisotropy in subzone A is relatively weak, although the Indian plate under-thrusts the Chinese mainland and pushes the Sanjiang lateral collision zone towards east to ENE, resulting in weak strike-slip in the west part of the study area. In the same area, there is also a special exclusive tectonic zone where surface movement suddenly changes direction, from southeastwards, southwards to southwestwards (Zhang et al 2004;Gupta et al 2015;Jin et al 2019). Time delay in subzone B is larger than that in subzone A, but smaller than in subzone C. Several faults go through this zone and intersect one another.…”

Section: M P L I C a T I O N S O F S H E A R -W A V E S P L I T T Imentioning

confidence: 99%

“…In addition, it is an important metallogenic belt in China (Hou et al 2006;Li et al 2018). According to the surface velocity field obtained by GPS data, the direction of surface movement altered from eastwards to southeastwards, and then to direct southwards (Zhang et al 2004;Gupta et al 2015;Jin et al 2019). Located in the south of the North-South Seismic Belt in China, the Sanjiang lateral collision zone is seismically active with frequent occurrence of strong earthquakes.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Preliminary analysis of crustal shear‐wave splitting in the Sanjiang lateral collision zone of the southeast margin of the Tibetan Plateau and its tectonic implications

Gao

Chen

Zhang

et al. 2019

Geophysical Prospecting

View full text Add to dashboard Cite

The collision of the Indian and Eurasian plates, to the east of the eastern Himalayan syntaxes, forms the Sanjiang lateral collision zone in the southeast margin of the Tibetan Plateau, where there are intense crustal deformation, active faults, earthquakes, as well as a metallogenic belt. Given the lack of adequate seismic data, shear‐wave splitting in this area has not been studied. With seismic data from a temporary seismic linear array, as well as permanent seismic stations, this paper adopts the identification on microseismic event to pick more events and obtains shear‐wave splitting parameters from local earthquakes. From the west to the east, the study area can be divided into three subzones. The “fast” polarization (i.e. the polarization of the fast shear wave) varies gradually from NNW to NS to NNE in these three subzones. The time delay of the slow shear wave (i.e. the time difference between the two split shear waves) also increases in the same direction, indicating the presence of seismic anisotropy above 25 km in the crust. Both shear‐wave splitting parameters are closely related to stress, faults and tectonics. The scatter and the “dual” (i.e. two) dominant orientations of the fast polarizations at several stations indicate strong distortions caused by nearby faults or deep tectonics. The anisotropic parameters are found to be related to some degree to the metallogenic belt. It is worth to further analyse the link between the anisotropic pattern and the metallogenic area, which suggests that shear‐wave splitting could be applied to study metallogeny. This paper demonstrates that the identification on microseismic event is a useful tool in detecting shear‐wave splitting details and exploring its tectonic implications.

show abstract

Section: Fast Polarizationsupporting

confidence: 88%

Section: M P L I C a T I O N S O F S H E A R -W A V E S P L I T T Imentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Preliminary analysis of crustal shear‐wave splitting in the Sanjiang lateral collision zone of the southeast margin of the Tibetan Plateau and its tectonic implications

Gao

Chen

Zhang

et al. 2019

Geophysical Prospecting

View full text Add to dashboard Cite

show abstract

“…The present‐day deformation deduced from GPS data reveals crustal shortening that accommodates India's penetration into Eurasia (Wang, ). Recent GPS measurements (in a stable Eurasian frame) from Northeast India also show a clear evidence of northeast directed penetration of a rigid Indian plate into a less rigid Eurasian plate (Gupta et al, ). The strike parallel FPDs in the Arunachal Himalaya could be associated with extension due to the deformation induced by high convergence rate and plate motion in the northeastward direction.…”

Section: Discussionmentioning

confidence: 98%

Mantle Deformation in the Eastern Himalaya, Burmese Arc and Adjoining Regions

Saikia

Kumar

Singh

et al. 2018

Geochem Geophys Geosyst

View full text Add to dashboard Cite

This study presents new results of shear wave splitting at 56 broadband stations installed in the Eastern Himalaya, Burmese Arc, and adjoining regions. The fast polarization directions (FPDs) within the Himalaya, Burmese Arc and the foredeep are parallel to the strike of the orogens, suggesting a coherently deformed lithospheric mantle under compression. The FPDs follow the Main Boundary Thrust and the Main Central Thrust in the central segment of the Arunachal Himalaya. Smaller delay times (∼0.7 s) can be best explained by multiple layers of anisotropy, where combined effects of the anisotropic fabric of a coherently deformed lithosphere of the Arunachal Himalaya and plate motion related strain are playing a role. Null measurements in the Siang window may be due to the Indian plate interaction with Eurasia and Burma plates, causing different layers of anisotropy. Another possibility is the coincidence of source polarization direction with the fast axis. In the Bengal Basin, the Nulls could be due to annihilation of frozen anisotropy in the downwelling Indian lithosphere and the APM‐related strain, or a highly heterogeneous mantle affected by the Kereguelen plume magmatism, at ∼116 Ma.

show abstract

“…The postfit residuals of the velocities are less than 1.0 mm/yr for the 10 fiducial sites, which demonstrates that the region occupied by these sites is indeed tectonically stable and our result is with high accuracy. We further incorporate several velocity solutions from previous studies (Kreemer et al, [which is a compilation of results of many other studies]; Devachandra et al, ; Gupta et al, ; Marechal et al, ; Vernant et al, ), to provide better coverage of the tectonic deformation field in the surrounding continental regions of China, especially the Himalaya and western Tien Shan regions. We transform these velocity solutions to coincide with our solution by rigid body rotation, minimizing postfit residuals at the common sites.…”

Section: Gps Data Data Processing and Displacement Modelingmentioning

confidence: 99%

Present‐Day Crustal Deformation of Continental China Derived From GPS and Its Tectonic Implications

2020

View full text Add to dashboard Cite

We process rigorously GPS data observed during the past 25 years from continental China to derive site secular velocities. Analysis of the velocity solution leads to the following results. (a) The deformation field inside the Tibetan plateau and Tien Shan is predominantly continuous, and large deformation gradients only exist perpendicular to the Indo‐Eurasian relative plate motion and are associated with a few large strike‐slip faults. (b) Lateral extrusions occur on both the east and west sides of the plateau. The westward extrusion peaks at ~6 mm/yr in the Pamir‐Hindu Kush region. A bell‐shaped eastward extrusion involves most of the plateau at a maximum rate of ~20 mm/yr between the Jiali and Ganzi‐Yushu faults, and the pattern is consistent with gravitational flow in southern and southeastern Tibet where the crust shows widespread dilatation at 10–20 nanostrain/yr. (c) The southeast borderland of Tibet rotates clockwise around the eastern Himalaya syntaxis, with sinistral and dextral shear motions along faults at the outer and inner flanks of the rotation terrane. The result suggests gravitational flow accomplished through rotation and translation of smaller subblocks in the upper crust. (d) Outside of the Tibetan plateau and Tien Shan, deformation field is block‐like. However, unnegligible internal deformation on the order of a couple of nanostrain/yr is found for all blocks. The North China block, under a unique tectonic loading environment, deforms and rotates at rates significantly higher than its northern and southern neighboring blocks, attesting its higher seismicity rate and earthquake hazard potential than its neighbors.

show abstract

Kinematics and strain rates of the Eastern Himalayan Syntaxis from new GPS campaigns in Northeast India

Cited by 64 publications

References 52 publications

Preliminary analysis of crustal shear‐wave splitting in the Sanjiang lateral collision zone of the southeast margin of the Tibetan Plateau and its tectonic implications

Preliminary analysis of crustal shear‐wave splitting in the Sanjiang lateral collision zone of the southeast margin of the Tibetan Plateau and its tectonic implications

Mantle Deformation in the Eastern Himalaya, Burmese Arc and Adjoining Regions

Present‐Day Crustal Deformation of Continental China Derived From GPS and Its Tectonic Implications

Contact Info

Product

Resources

About