“…7 ) moves ~3 mm/yr southward relative to cGPS sites CSOS/SHIL and GHTU in the Shillong Plateau and Assam Valley. The motion between these sites is attributable to the slip along Kopili fault which fragments the Assam Valley and is consistent with previously reported rates 15 , 55 . Figure 7 Velocities tipped with 95% confidence error ellipse of GPS sites in northeastern India and the Indo Burmese Arc in an India-fixed frame of reference.…”
Section: Resultssupporting
confidence: 90%
“…7 ), with some of the faults being reported to be active. India –fixed velocities of Shillong plateau and Assam valley cGPS sites during the study period indicate southward motion of ~7 mm/yr with respect to the stable Indian shield which is consistent with the rates reported earlier 12 , 55 . Campaign GPS measurements 55 , 56 indicate clockwise rotation of Shilling plateau and Assam valley which they attribute to their locations between the Indo-Eurasian and India-Sunda convergence zones.…”
Section: Resultssupporting
confidence: 89%
“…Shillong Plateau and Assam Valley in Northeast India behaves as a distinct block moving southward at a rate of ~7 mm/yr with reference to the plate interior and consistent with the clock wise rotation of this block reported earlier 55 . Shortening and extension rates recorded by cGPS sites in Shillong Plateau, Assam Valley and IBA are consistent with the fragmentation of Assam Valley by Kopili fault and segmented deformation related to the salient-recess topography and faults in Indo Burmese Arc 12 , 55 . To the south of IBA, Port Blair site in the Andaman subduction zone to the east of Indian plate moves ~48 mm/yr SW with ~16 mm/yr uplift during ~4 year period (2012–2015), thus defining the upper bound of the ongoing active post-seismic relaxation in this region.…”
Section: Discussionsupporting
confidence: 88%
“…Indo-Burmese Arc is accommodating about half of the 36 mm/yr relative motion between the India and Sunda plates 10 , 57 – 59 . Baseline lengths between these sites indicate extension of ~3 mm/yr between LUMA and IMPH and shortening of ~9 mm/yr between IMPH and AIZW indicating segmented deformation related to the salient-recess topography and faults in this region 12 , 55 . An approximately E-W baseline (GHTU-LUMA) between Shillong Plateau and IBA indicates shortening of ~3.6 mm/yr in this region which is due to the subduction of IBA.…”
We estimate a new angular velocity for the India plate and contemporary deformation rates in the plate interior and along its seismically active margins from Global Positioning System (GPS) measurements from 1996 to 2015 at 70 continuous and 3 episodic stations. A new India-ITRF2008 angular velocity is estimated from 30 GPS sites, which include stations from western and eastern regions of the plate interior that were unrepresented or only sparsely sampled in previous studies. Our newly estimated India-ITRF2008 Euler pole is located significantly closer to the plate with ~3% higher angular velocity than all previous estimates and thus predicts more rapid variations in rates and directions along the plate boundaries. The 30 India plate GPS site velocities are well fit by the new angular velocity, with north and east RMS misfits of only 0.8 and 0.9 mm/yr, respectively. India fixed velocities suggest an approximate of 1–2 mm/yr intra-plate deformation that might be concentrated along regional dislocations, faults in Peninsular India, Kachchh and Indo-Gangetic plain. Relative to our newly-defined India plate frame of reference, the newly estimated velocities for 43 other GPS sites along the plate margins give insights into active deformation along India’s seismically active northern and eastern boundaries.
“…7 ) moves ~3 mm/yr southward relative to cGPS sites CSOS/SHIL and GHTU in the Shillong Plateau and Assam Valley. The motion between these sites is attributable to the slip along Kopili fault which fragments the Assam Valley and is consistent with previously reported rates 15 , 55 . Figure 7 Velocities tipped with 95% confidence error ellipse of GPS sites in northeastern India and the Indo Burmese Arc in an India-fixed frame of reference.…”
Section: Resultssupporting
confidence: 90%
“…7 ), with some of the faults being reported to be active. India –fixed velocities of Shillong plateau and Assam valley cGPS sites during the study period indicate southward motion of ~7 mm/yr with respect to the stable Indian shield which is consistent with the rates reported earlier 12 , 55 . Campaign GPS measurements 55 , 56 indicate clockwise rotation of Shilling plateau and Assam valley which they attribute to their locations between the Indo-Eurasian and India-Sunda convergence zones.…”
Section: Resultssupporting
confidence: 89%
“…Shillong Plateau and Assam Valley in Northeast India behaves as a distinct block moving southward at a rate of ~7 mm/yr with reference to the plate interior and consistent with the clock wise rotation of this block reported earlier 55 . Shortening and extension rates recorded by cGPS sites in Shillong Plateau, Assam Valley and IBA are consistent with the fragmentation of Assam Valley by Kopili fault and segmented deformation related to the salient-recess topography and faults in Indo Burmese Arc 12 , 55 . To the south of IBA, Port Blair site in the Andaman subduction zone to the east of Indian plate moves ~48 mm/yr SW with ~16 mm/yr uplift during ~4 year period (2012–2015), thus defining the upper bound of the ongoing active post-seismic relaxation in this region.…”
Section: Discussionsupporting
confidence: 88%
“…Indo-Burmese Arc is accommodating about half of the 36 mm/yr relative motion between the India and Sunda plates 10 , 57 – 59 . Baseline lengths between these sites indicate extension of ~3 mm/yr between LUMA and IMPH and shortening of ~9 mm/yr between IMPH and AIZW indicating segmented deformation related to the salient-recess topography and faults in this region 12 , 55 . An approximately E-W baseline (GHTU-LUMA) between Shillong Plateau and IBA indicates shortening of ~3.6 mm/yr in this region which is due to the subduction of IBA.…”
We estimate a new angular velocity for the India plate and contemporary deformation rates in the plate interior and along its seismically active margins from Global Positioning System (GPS) measurements from 1996 to 2015 at 70 continuous and 3 episodic stations. A new India-ITRF2008 angular velocity is estimated from 30 GPS sites, which include stations from western and eastern regions of the plate interior that were unrepresented or only sparsely sampled in previous studies. Our newly estimated India-ITRF2008 Euler pole is located significantly closer to the plate with ~3% higher angular velocity than all previous estimates and thus predicts more rapid variations in rates and directions along the plate boundaries. The 30 India plate GPS site velocities are well fit by the new angular velocity, with north and east RMS misfits of only 0.8 and 0.9 mm/yr, respectively. India fixed velocities suggest an approximate of 1–2 mm/yr intra-plate deformation that might be concentrated along regional dislocations, faults in Peninsular India, Kachchh and Indo-Gangetic plain. Relative to our newly-defined India plate frame of reference, the newly estimated velocities for 43 other GPS sites along the plate margins give insights into active deformation along India’s seismically active northern and eastern boundaries.
“…GPS derived surface convergence rates along the arc normal transects of rest of Himalaya (Fig. 2) from west to east are ~ 16 mm/year in Ladakh, ~ 13 mm/year in Gharwal, ~ 18 mm/year in Kumaon, ~ 13 mm/year in Nepal Himalaya, ~ 10 mm/year in Sikkim, ~ 12 mm/year in Bhutan and ~ 15 mm/year in Arunachal Himalaya 15,[19][20][21][22] . Kashmir valley recorded arc-parallel extension rate of about 7 mm/year from our cGPS sites ( Fig.…”
We present GPS velocities in Kashmir valley and adjoining regions from continuous Global Positioning System (cGPS) network during 2008 to 2019. Results indicate total arc normal shortening rates of ~ 14 mm/year across this transect of Himalaya that is comparable to the rates of ~ 10 to 20 mm/year reported else-where in the 2500 km Himalaya Arc. For the first time in Himalayas, arc-parallel extension rate of ~ 7 mm/year was recorded in the Kashmir valley, pointing to oblique deformation. Inverse modeling of the contemporary deformation rates in Kashmir valley indicate oblique slip of ~ 16 mm/year along the decollement with locking depth of ~ 15 km and width of ~ 145 km. This result is consistent with the recorded micro-seismicity and low velocity layer at a depth of 12 to 16 km beneath the Kashmir valley obtained from collocated broadband seismic network. Geodetic strain rates are consistent with the dislocation model and micro-seismic activity, with high strain accumulation (~ 7e−08 maximum compression) to the north of Kashmir valley and south of Zanskar ranges. Assuming the stored energy was fully released during 1555 earthquake, high geodetic strain rate since then and observed micro-seismicity point to probable future large earthquakes of Mw ~ 7.7 in Kashmir seismic gap.
Research on the Bengal Basin, the most important sedimentary basin in the world that supports ~200 million people, is primarily focused on its geologic evolution and anthropogenic effects, yet the basin is poorly studied in terms of geomorphic response to tectonic activity. The eastern part of the Bengal Basin is characterized by the Chittagong Tripura Fold Belt (CTFB) and the Indo‐Burman Range (IBR), which have structurally deformed into a series of mostly compressional fold and thrust belts including strike–slip faults because of the ongoing subduction‐related convergence between the Eurasian Plate and the Indian Plate. A network of river channels incising through thick sedimentary rocks and crossing and/or flowing parallel to this fold and thrust Belt. The active tectonic deformation caused by the structures and ongoing compression‐related activity remains enigmatic due to the sparse dataset, thick vegetation cover, outcrop paucity, and the Basin's complex geology. In this paper, we investigate river response to ongoing tectonics in the CTFB and western IBR by analysing channel geomorphic metrics (ksn, χ, and knickpoints) coupled with river profile forms derived from 30 m resolution NASADEM. Our results reveal (1) several convex and double‐concave reaches of major rivers and their tributaries that primarily indicate the transient state of the rivers; (2) a total of 219 upstream propagating knickpoints including distinct knickzones in profile reaches, suggesting river profile adjustment; (3) two different ksn zones in the CTFB and IBR with high ksn zone to the east and low ksn zone to the west, where ksn values range from 0 to 4905. These zones are thought to be associated with the differential uplift rate of the two east‐dipping thrust fault systems, the Kaladan Fault and Chittagong Cox's Bazar Fault (CCF); and (4) the χ‐ map (values ranging from 0.47 to 19,631.75) shows an occasional transient state of drainage divides where divides are migrating to the east, west, and north‐east, and χ versus elevation plots exhibiting disequilibrium state of the rivers suggesting that these drainage basins are likely adjusting with tectonic activities. Thus, our empirical observation suggests that the major rivers and their tributaries are in a transient state related to the region's overall ongoing tectonics.
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