Evidence of the 1950 Great Assam Earthquake Surface Break Along the Mishmi Thrust at Namche Barwa Himalayan Syntaxis

Singh, Iqbal; Pandey, Arjun; Mishra, Rajeeb Lochan; Priyanka, Rao Singh; Brice, Atul; Jayangondaperumal, R.; Srivastava, Vaibhav

doi:10.1029/2020gl090893

Cited by 23 publications

(4 citation statements)

References 41 publications

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“…Short (∼10-m-long) trenches typically miss broadscale folding on either side of the thrust (Table S4 in Supporting Information S1). Post-seismic erosion of the hanging wall fosters thick and broad post-seismic colluvial deposition on the footwall, which commonly smooths and tapers apparent vertical offsets, as observed, for instance, across the surface break of the 1950 Assam earthquake (e.g., Coudurier-Curveur et al, 2020;Singh et al, 2021).…”

Section: Rupture Behavior Characteristic Slip and Post-glacial Return...mentioning

confidence: 98%

Post‐20 ka Earthquake Scarps Along NE‐Tibet's Qilian Shan Frontal Thrust: Multi‐Millennial Return, ∼Characteristic Co‐Seismic Slip, and Geological Rupture Control

Xu²,

Chen

et al. 2021

JGR Solid Earth

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Section: Rupture Behavior Characteristic Slip and Post-glacial Return...mentioning

confidence: 98%

Post‐20 ka Earthquake Scarps Along NE‐Tibet's Qilian Shan Frontal Thrust: Multi‐Millennial Return, ∼Characteristic Co‐Seismic Slip, and Geological Rupture Control

Xu²,

Chen

et al. 2021

JGR Solid Earth

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“…Palaeoseismological study in the frontal Mishmi Ranges had an estimated dip‐slip of 24.6 ± 4.6 m for a 25 ± 5°E dipping fault during the 1950 Assam earthquake (Singh et al, 2021). Interestingly, the 1950 earthquake nucleated further east of the Tuting–Tidding Suture Zone, where the locked zone that demarcates the brittle and ductile segments of Main Himalayan Thrust (MHT) occurs.…”

Section: Introductionmentioning

confidence: 99%

“…Across the ~65‐km‐wide seismo‐potential locked zone of the Mishmi Range, a global positioning system (GPS) convergence rate of 20 mm/year was proposed (Devachandra, Kundu, Catherine, Kumar, & Gahalaut, 2014). If it is assumed that all previously accumulated interseismic strain was released by the 1950 Assam earthquake ( M w 8.6), a slip deficit of ~1.4 m is capable of generating an M w ~ 7.7 earthquake along the Mishmi Thrust in the present day (Singh et al, 2021). Furthermore, a calculated dip‐slip of 15.3 ± 4.6 m is demonstrated to be due to the rupture produced by the great 1,697 CE Sadiya earthquake.…”

Section: Introductionmentioning

confidence: 99%

Brittle tectonics in the western Arunachal Himalayan frontal fold belt, northeast India: Change in stress regime from pre‐collisional extension to collisional compression

et al. 2022

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The study of brittle deformation of the collisional mountains can explain its shallow crustal tectonic evolution and the palaeostress regime. The Main Boundary Thrust (MBT) zone in the western Arunachal Himalaya displays imbrication in the Permian Gondwana sequence between the MBT‐1 (/Bome Thrust/MBT‐Upper) in the north and MBT‐2 (/MBT‐Lower) in the south with consistent northerly dip. The Lower Gondwana rocks occur in the footwall of the MBT‐1 with the Proterozoic Bomdila Group in the hangingwall. The upper Gondwana rocks constitute the hangingwall sequence for the MBT‐2 with Neogene Siwalik rocks in the footwall. This article analyses palaeostress using brittle fractures in the Gondwana rocks that crop out for ~120 km2 in the study area. The fault‐bounded imbricate zone depicts eight brittle shear indicators and four sets of joints (J1 and J2: inclined and J3 and J4: subvertical). The signatures of the inherited pre‐Himalayan extensional deformation are preserved in the Lower Gondwana Miri Formation. The Bichom and Bhareli rocks exhibit brittle deformation features of the Himalayan Orogeny under strong ~N‐S compression. The palaeostress analysis of all joint sets indicates three phases of brittle deformation in the Gondwana and Siwalik rocks of the area. The subvertical joint sets and normal faults in the Miri Formation indicate a north‐northwest (NNW)‐directed extensional phase of the pre‐Himalayan origin. The inclined joint sets of the Bichom and Bhareli formations of the Gondwana sequence depict Himalayan orogeny with ~N‐S compressional phases. The third phase of brittle deformation in the Siwalik sequence depicts an east‐west (~E‐W) extension. The arc‐parallel extension in the frontal fold belt of the Arunachal Himalaya may be due to oblique India‐Asia collisional tectonics.

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“…Youngs and Coppersmith 1986;Field et al 2009Field et al , 2014Rong et al 2020). We adopted a combined MFT and MT rupture as the seismogenic fault of the Assam earthquake (Coudurier-Curveur et al 2020;Singh et al 2021). Generally, seismicity is assumed to follow the Gutenberg-Richter (GR) law (Gutenberg and Richter, 1944).…”

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confidence: 99%

Seismic moment deficit and hazard assessment of the Eastern Himalayan Syntaxis

Zhang,

Pan

2024

Preprint

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The largest earthquake ever recorded on land, the Assam Mw8.6 earthquake, occurred in the Eastern Himalayan Syntaxis (EHS), which has caused great concern regarding seismic hazard in this region. The seismic potential of the major faults in the EHS was evaluated by comparing the accumulation and release of seismic moments. First, constrained by the latest long-term global positioning system (GPS) measurements, the slip rates and locking depths of major faults in the EHS were calculated using a three-dimensional (3D) elastic block model. Second, the seismic moment release of the major faults in the EHS from 1800 to 2022 was estimated using an earthquake catalog. The results show that the seismic moment deficit of the western and eastern Bhutan and Assam segments of the Main Himalayan Thrust (MHT) are 2.6 × 10 21, 2.0 × 10 21 and 7.5 × 10 20 N · m, which are equivalent to seismic moments of Mw 8.3, 8.2 and 7.9, respectively. The MHT remains a major source of future seismic hazards in the EHS. In addition, the Jiali Fault and Naga Thrust were capable of generating earthquakes of Mw 7.4. This study also shows that if the seismicity of the MHT follows the Gutenberg–Richter (GR) law, the recurrence period of the Assam earthquake is approximately 2100 year.

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Evidence of the 1950 Great Assam Earthquake Surface Break Along the Mishmi Thrust at Namche Barwa Himalayan Syntaxis

Abstract: Several paleoseismological trenches excavated along the eastern Himalayan front since last two decades have provided insight into the rupture dynamics of several earthquakes in

Cited by 23 publications

References 41 publications

Post‐20 ka Earthquake Scarps Along NE‐Tibet's Qilian Shan Frontal Thrust: Multi‐Millennial Return, ∼Characteristic Co‐Seismic Slip, and Geological Rupture Control

Post‐20 ka Earthquake Scarps Along NE‐Tibet's Qilian Shan Frontal Thrust: Multi‐Millennial Return, ∼Characteristic Co‐Seismic Slip, and Geological Rupture Control

Brittle tectonics in the western Arunachal Himalayan frontal fold belt, northeast India: Change in stress regime from pre‐collisional extension to collisional compression

Seismic moment deficit and hazard assessment of the Eastern Himalayan Syntaxis

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