Crustal deformation analysis across Garhwal Himalaya: Part of western Himalaya using GPS observations

Sharma, Gopal; Kannaujiya, Suresh; Gautam, Param K.; Taloor, Ajay Kumar; Champatiray, P. K.; Mohanty, S.

doi:10.1016/j.quaint.2020.08.025

Cited by 34 publications

(5 citation statements)

References 39 publications

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“…Generated long time series of each station coordinates are corrected for outliers and velocities were estimated in the International Terrestrial Reference Frame (ITRF) (Table 1 ). We also used the data from published works 14 , 33 , 53 – 56 along with our data. All the published data are converted to the ITRF 2008 reference frame and estimated the velocities in the Indian reference frame using the pole of rotation of Ader 32 .…”

Section: Discussionmentioning

confidence: 99%

Crustal velocity and interseismic strain-rate on possible zones for large earthquakes in the Garhwal–Kumaun Himalaya

Pappachen

Sathiyaseelan

Gautam

et al. 2021

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The possibility of a major earthquake like 2015 Gorkha–Nepal or even greater is anticipated in the Garhwal–Kumaun region in the Central Seismic Gap of the NW Himalaya. The interseismic strain-rate from GPS derived crustal velocities show multifaceted strain-rate pattern in the region and are classified into four different strain-rate zones. Besides compressional, we identified two NE–SW orienting low strain rate (~ 20 nstrain/a) zones; namely, the Ramganga-Baijro and the Nainital-Almora, where large earthquakes can occur. These zones have surface locking widths of ~ 72 and ~ 75 km respectively from the Frontal to the Outer Lesser Himalaya, where no significant surface rupture and associated large earthquakes were observed for the last 100 years. However, strain reducing extensional deformation zone that appears sandwiched between the low strain-rate zones pose uncertainties on the occurences of large earthquakes in the locked zone. Nevertheless, such zone acts as a conduit to transfer strain from the compressional zone (> 100 nstrain/a) to the deforming frontal active fault systems. We also observed a curvilinear surface strain-rate pattern in the Chamoli cluster and explained how asymmetric crustal accommodation processes at the northwest and the southeast edges of the Almora Klippe, cause clockwise rotational couple on the upper crust moving over the MHT.

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Section: Discussionmentioning

confidence: 99%

Crustal velocity and interseismic strain-rate on possible zones for large earthquakes in the Garhwal–Kumaun Himalaya

Pappachen

Sathiyaseelan

Gautam

et al. 2021

Sci Rep

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“…The published results of geodetic studies carried out by previous workers suggest building of a slip deficit between the HFT and the MBT over a width of about 100 km with a long‐term slip rate of 14 ± 1 mm/year (Banerjee & Bürgman, 2002; Bilham et al, 1997; Jouanne et al, 1999, 2004; Larson et al, 1999; Yadav et al, 2019). Similarly, accumulation of higher strain in the MCT zone and the inner part of the Lesser Himalayan region of Uttarakhand with a convergence rate of 15 mm/year has also been processed (Dumka et al, 2018; Jade et al, 2017; Mondal et al, 2016; Ponraj et al, 2011; Saji et al, 2020; Sharma et al, 2020; Yadav et al, 2020). The geodetic velocities of Mondal et al (2016) and Yadav et al (2020) are provided in (Table 2).…”

Section: Discussionmentioning

confidence: 99%

“…Similarly, accumulation of higher strain in the MCT zone and the inner part of the Lesser Himalayan region of Uttarakhand with a convergence rate of 15 mm/year has also been processed (Dumka et al, 2018;Jade et al, 2017;Mondal et al, 2016;Ponraj et al, 2011;Saji et al, 2020;Sharma et al, 2020;Yadav et al, 2020). The geodetic velocities of Mondal et al (2016) and Yadav et al (2020) are provided in (Table 2).…”

Section: Discussionmentioning

confidence: 99%

Active tectonics in the Main Boundary Thrust zone, Garhwal Himalaya, as evident from palaeoseismic signatures, morphotectonic features and PSI base ground deformation

2022

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In the Garhwal Himalaya, the steeply inclined Main Boundary Thrust (MBT) is characterized by landforms that indicate towards tectonic activity in the recent past. Linear active fault trace, sub‐recent fault scarps, strath terrace, uplifted terraces, deflected drainage, and triangular facet cones are some of the morphotectonic evidences of recent tectonic activity along the MBT. The MBT is defined by active fault trace in the form of linear depression and shows a prominent slope break across it. Thrusting of the Lesser Himalayan bedrocks over the colluvial deposits and back tilting of the colluvial deposits are also observed in the MBT zone. The formation of the sag pond and the deposition of the Quaternary lacustrine sediments followed by the deformation of the lacustrine deposits indicate phases of tectonic activities along the MBT. The later phase of deformation is represented by the folded lacustrine and colluvial deposits, where the amplitude of the fold measures about 3 m‐high and the deformed section measures about 23 m in length. The ongoing deformation patterns of the MBT zone have also been monitored with the help of Synthetic Aperture Radar‐based time series analysis. We used Sentinel‐1C dataset in ascending direction with polarization of the VV+ VH acquired between December 2, 2017 to September 7, 2021 to identify phase changes caused by ongoing active deformation. The Persistent Scatterer Interferometry (PSI) result based on Sentinel‐1A suggests that the Dehradun–Mussoorie and adjoining region has undergone an average deformation of 5.5 to −11 mm/year and the ground displacement of 1.5 to −3.8 cm. The time series analysis reveals that the Mussoorie hills in the MBT zone have higher rate of deformation.

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“…Over time, these thrust faults in the Himalayas that accommodate the crustal shortening changed significantly (O'Kane et al, 2022). The Himalayan arc as a whole is seismically active, and recent geodetic studies based primarily on GPS measurements in the eastern, central, and western Himalayas found that the rate of convergence, strain accumulation, and deformation of the Indian Plate varies significantly in different segments, both parallel and orthogonal (Ader et al, 2012;Banerjee et al, 2008;Bisht et al, 2021;Dumka et al, 2014Dumka et al, , 2018Jade et al, 2014Jade et al, , 2017Jouanne et al, 2014Jouanne et al, , 2020Kundu et al, 2014;Sharma et al, 2021). The crustal shortening and convergence across the western Himalayas have been accommodated by several thrust and strike-slip faults such as Main Central Thrust (MCT), Panjal Thrust (PT), Main Boundary Thrust (MBT), Jhelum strike-slip Fault (JF), Kashmir Boundary Thrust (KBT), Riasi Thrust (RT), Nathia Gali Thrust (NT) and Salt Range Thrust (SRT) (M. R. Khan et al, 2016;Figure 1b).…”

Section: Introductionmentioning

confidence: 99%

Crustal study based on integrated geophysical techniques in the Northwestern Himalayas, Pakistan

2023

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The present research aims to explicate the tectonics of the northwest Himalayas, Pakistan, based on integrated gravity, magnetic and earthquake data. The raw gravity and magnetic data were processed, and seven isoanomaly maps were prepared for qualitative interpretation, whereas a gravity model was prepared along the selected profile for quantitative interpretation. The local earthquake data have also been used to identify the various seismogenic layers in the subsurface and to understand how seismicity relates to regional structural features. Three northwest-trending thickskinned blind basement faults are identified from the present study, namely the Indus Kohistan Seismic Zone (IKSZ), Bagh Basement Fault and Hazara Lower Seismic Zone. The IKSZ is the tectonically most active among them and responsible for the 2005 Kashmir earthquake (Mw = 7.6) and 1974 Pattan earthquake (Mw = 6.2) in the region. The present study also delineated the prominent location of the Main Central Thrust in which the high-grade metamorphic rocks of Higher Himalayan Crystalline thrust over low-grade metamorphic rocks of Lesser Himalayas along this thickskinned fault. The field evidence such as ductile deformation, zone of inverted metamorphism, and brittle deformation also confirm this location. The sharp bending of the crystalline crust, as well as deep basement just south of Kohistan Island Arc (KIA), indicate that the high density and susceptibility rocks of this arc thrust on the leading margin of the Indian Plate along the Main Mantle Thrust. This thrust fault is a major suture zone separating the KIA in the north from the Indian Plate in the south. The other faults in the region exist in the sedimentary/meta-sedimentary wedge and are thin-skinned. It is inferred from the current investigation that the study area exhibits a composite style of deformation. Moreover, the gravity model combined with earthquake data suggested the existence of multiple décollement zones below the Hazara-Kashmir Syntaxis. The model envisaged an increase in the thickness of the Indian Plate continental crust in the northeast direction.

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Crustal deformation analysis across Garhwal Himalaya: Part of western Himalaya using GPS observations

Cited by 34 publications

References 39 publications

Crustal velocity and interseismic strain-rate on possible zones for large earthquakes in the Garhwal–Kumaun Himalaya

Crustal velocity and interseismic strain-rate on possible zones for large earthquakes in the Garhwal–Kumaun Himalaya

Active tectonics in the Main Boundary Thrust zone, Garhwal Himalaya, as evident from palaeoseismic signatures, morphotectonic features and PSI base ground deformation

Crustal study based on integrated geophysical techniques in the Northwestern Himalayas, Pakistan

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