An appraisal of crustal structure of the Indo-Burmese subduction region

Saikia, Sowrav; Baruah, Santanu; Chopra, Sumer; Gogoi, Bibhuti; Singh, Upendra; Bharali, Bubul

doi:10.1016/j.jog.2019.05.002

Cited by 17 publications

(17 citation statements)

References 52 publications

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“…The Burmese region is the most seismically active zone in the Indian plate, where the Indian plate is underthrusting beneath the Burmese plate (Gahalaut & Kundu, 2016). The NNW-SSE-to NE-SWtrending Burmese region is extended up to 700 km and has a width of 250 km (Saikia et al, 2019). The average crustal thickness is * 43 km (Saikia et al, 2019).…”

Section: Burmese Regionmentioning

confidence: 99%

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Simulation of Intraplate Stress Distribution of the Indian Tectonic Plate Using the Finite Element Method

Bahuguna

Shanker

2021

Pure Appl. Geophys.

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The intraplate stress field distribution is estimated by considering the isotropic elastic properties of the Indian plate using numerical analysis. In most modelling, the intraplate stresses are typically established on applying plate-driving forces to a homogeneous elastic plate. However, a tectonic plate comprises continental and oceanic lithosphere with sedimentary basins, cratons, and fold belts with varying significant differences in elastic properties, which likely affect the magnitude and pattern of stress and deformation. In the present study, the finite element method (FEM)-based software packages ABAQUS is used to simulate the intraplate stress distribution in the plate using a 3D mechanical model incorporating the elastic properties of the 19 geological regions of the Indian subcontinent and oceanic region. FEM models are validated with Indian plate fixed GPS velocities and found to be in reasonable agreement with the plate's velocity. This study can augment the interpretability of seismic and geological studies. Also, the model can be helpful to perform seismic hazard assessment (using the stress estimated with the FEM model), identify the seismically active zones and collect insight on active intraplate deformation of seismically active regions of the Indian plate by interpreting the strain rate, deformation rate and stress distribution data.

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Section: Burmese Regionmentioning

confidence: 99%

“…The NNW-SSE-to NE-SWtrending Burmese region is extended up to 700 km and has a width of 250 km (Saikia et al, 2019). The average crustal thickness is * 43 km (Saikia et al, 2019). There are a number of tectonic domains developed due to E-W directed compressive stresses induced by the subduction process (Baruah et al, 2013).…”

Section: Burmese Regionmentioning

confidence: 99%

Simulation of Intraplate Stress Distribution of the Indian Tectonic Plate Using the Finite Element Method

Bahuguna

Shanker

2021

Pure Appl. Geophys.

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“…The V S for the observed depth section is less than 4.0 km/s and therefore it is not possible to demarcate the Moho discontinuity. Along this E‐W directed path the Indian Plate is subducting beneath the Burma Plate (Saikia et al, 2019), and therefore it may be difficult to identify the Moho. Gradually increasing V S with increasing depth reaches the maximum value at 45–50 km depth followed by a decrease, low value for the section 50–70 km and a minimum at 60–65 km depth.…”

Section: Resultsmentioning

confidence: 99%

Along‐strike variation in the shear wave crustal structure of the NE Himalayan and Indo‐Burmese arc: Evidence based on surface wave dispersion analysis

Chanu

Kumar

Kumar³

et al. 2022

Geological Journal

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Surface wave dispersion data is used to infer the shear wave velocity structure variation in the north‐east Himalaya and Indo‐Burmese arc regions. We have used 25 earthquakes data from four groups with a magnitude range of 5.0–6.7, epicentral distance range 368–800 km, and focal depth less than 50 km. Ray paths from the earthquake location to the seismic station are transversely passing different geotectonic units of the Himalayas, Indo‐Gangetic plains, and Indo‐Burma collision zones. The weighted average dispersion curve and the path averaged shear wave velocity models are computed for the four groups located at different azimuths around Shillong seismic station. Non‐linear least‐square inversion is performed to obtain the shear wave velocity structure of the crust and uppermost mantle from joint inversion of Rayleigh and Love waves group velocities. Subsequently, Rayleigh and Love waves group velocities are inverted separately to obtain vertical and horizontal components of S‐wave velocity. Next, using these components anisotropy coefficient values at different depths for each path are also estimated. A high variation of dispersion curves and the shear wave velocity models from one group to another indicates that the region is geotectonically very complex. An approximately 80 km‐thick zone beneath the study region has shear wave velocity as low as 1.7 km/s in the uppermost crust in the southern part and ~4.7 km in the uppermost mantle beneath the Eastern Himalayan Syntaxis (EHS). Inferred velocity is also lower than that of PREM and AK135 global models with a much thicker crust beneath the study region. Radial anisotropy varies even within the northern part from the Indo‐Eurasian collision zone to EHS and northern to southern Indo‐Burma ranges. Anisotropy is comparatively stronger in the deeper part below ~40 km for the three paths, except for the EHS, where the result is contrary.

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“…To understand the seismogenesis and geodynamic evolution of NE India, it is essential to study the crustal configuration. The collision and subduction tectonics in NE India resulted in lateral variations of crustal thickness and its compositions (Borah, Bora, Goyal, & Kumar, 2016; Hazarika, Arora, & Bora, 2012; Kundu, Hazarika, Hajra, Singh, & Ghosh, 2020; Mitra, Priestley, Bhattacharyya, & Gaur, 2005; Saikia et al, 2019). One of the best ways to understand the bulk composition of the crust is to estimate crustal Poisson's ratio.…”

Section: Introductionmentioning

confidence: 99%

“…It helps to draw petrological and geochemical inferences related to the mineralogical composition of the crust as well as its formation and geodynamic evolution. The receiver function (RF) analysis (Langston, 1979; Vinnik, 1977) is one of the most widely used techniques to estimate crustal thickness and average Poisson's ratio of crust in the Himalaya (e.g., Borah et al, 2016; Hajra, Hazarika, Bankhwal, Kundu, & Kumar, 2019; Hazarika, Kumar, & Yadav, 2013; Hazarika, Sen, & Kumar, 2014; Kundu et al, 2020; Paul & Mitra, 2017; Saikia et al, 2019; Wadhawan et al, 2017) and elsewhere (e.g., Chevrot & van der Hilst, 2000; Lombardi, Braunmiller, Kissling, & Giardini, 2008; Zhu & Kanamori, 2000).…”

Section: Introductionmentioning

confidence: 99%

Spatial variations of crustal thickness and Poisson's ratio in the northeastern region of India based on receiver function analysis

et al. 2022

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Crustal configuration beneath the northeastern region of India has been investigated with the help of receiver function (RF) analysis of teleseismic earthquakes recorded by 19 broadband seismological stations. We adopted the H‐k stacking method to estimate crustal thickness and Poisson's ratio beneath each recording station. The study reveals a large variation in crustal thickness and Poisson's ratio which are correlated with the complex geology and tectonics of the region. The crust is observed to be thinner (36.5–41.6 km) beneath Bengal Basin, Shillong Plateau, and the Brahmaputra valley compared to the Indo‐Burma Ranges (IBR) (~40–54 km) and Arunachal Higher Himalaya (TAWA station, ~45 km) and Sikkim Himalaya (GTK station, ~46.5 km). A large variation of Poisson's ratio is observed in the region (~0.230–0.306). Poisson's ratio is generally low‐to‐intermediate in the Shillong‐Mikir Plateau, Bengal Basin, and the Brahmaputra Valley, while it is intermediate‐to‐high in the Tripura Fold Belt and the northern part of the IBR. The high Poisson's ratio in the Tripura Fold Belt is due to the presence of basaltic basement rock and clay minerals existing in the sedimentary rocks, whereas the presence of partially serpentinized rock in the ophiolitic mélange complex causes a high Poisson's ratio in the IBR.

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An appraisal of crustal structure of the Indo-Burmese subduction region

Cited by 17 publications

References 52 publications

Simulation of Intraplate Stress Distribution of the Indian Tectonic Plate Using the Finite Element Method

Simulation of Intraplate Stress Distribution of the Indian Tectonic Plate Using the Finite Element Method

Along‐strike variation in the shear wave crustal structure of the NE Himalayan and Indo‐Burmese arc: Evidence based on surface wave dispersion analysis

Spatial variations of crustal thickness and Poisson's ratio in the northeastern region of India based on receiver function analysis

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