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Tsergo Ri landslide

January 01, 1970

The Tsergo Ri landslide was a prehistoric landslide in the Nepalese Himalaya, which took place around 51,000±13,000 years ago, during the Last Glacial Period. During the collapse, a mass of rock of about 10–15 cubic kilometres (2.4–3.6 cu mi) detached from a previous mountain or ridge and descended with a speed of about 450 kilometres per hour (120 m/s); later, glaciers eroded almost the entire landslide mass. Previously weakened rocks may have contributed to the collapse, which was probably started by an earthquake.

Geomorphology and geology edit

The collapse of Tsergo Ri took place in Nepal's Langtang valley,[1] perpendicular to the Himalaya[2] and about 60 kilometres (37 mi) north of the Nepalese capital Kathmandu.[3] The small settlement of Kyangjin Kharka lies at the foot of the landslide deposit.[4] With a volume of 10–15 cubic kilometres (2.4–3.6 cu mi),[2] it is one of the largest known mass movements on Earth[1] and perhaps the largest known landslide in crystalline bedrock.[5]

Causes and trigger edit

The collapse affected Himalayan gneiss rocks, which also contain migmatites and granites; they also include older pseudotachylite and ultramylonite rocks (both of which can be formed by collapses) and which acted as a sliding plane for the Tsergo Ri collapse.[6] Rocks formed by deformation, intrusions of granite, and layers of pyrrhotite ore, which are unstable under mechanical load and neotectonic faults, may have been weak structures that facilitated the collapse.[7][8]

The Tsergo Ri region is one of the fastest uplifting parts of the Himalaya.[9] The Tsergo Ri landslide was probably triggered by seismic activity,[10] perhaps on the Himalayan Main Central Thrust;[11] a water level drop in the Paleo Kathmandu Lake took place at the same time and may have been caused by the same earthquake.[12] The collapse occurred during a time of increased monsoon strength, which may have played a role in the collapse.[13]

Pre-landslide topography and landslide edit

Based on reconstructions of the pre-landslide topography, there may have been a 7,500–8,500 metres (24,600–27,900 ft) high[14][15] trilateral mountain in the area,[16] or a set of ridges.[17] The landslide detached in a southwest-west-southwest direction,[18] with the sliding mass breaking apart into blocks.[19] Owing to its fast speed of 450 kilometres per hour (120 m/s), rocks at the base of the slide melted.[20] The landslide impacted other mountains and ridges, sometimes destroying them[21] or triggering secondary collapses,[19] and may have mixed with glacier ice.[22]

It was eventually halted by topography such as the flanks of Pangshungtramo mountain[23] before it could become a debris avalanche.[24] The landslide debris consists of individual compact blocks on top of a basal breccia[25] and originally may have reached a thickness of 600–800 metres (2,000–2,600 ft).[26] Deformed structures inside the collapse debris indicate that small-scale movements occurred within the landslide.[18] The slide obstructed several glacial valleys.[27]

Timing and aftermath edit

The collapse took place about 51,000±13,000 years ago,[28] between two phases of the Würm glaciation.[29]

After the collapse, landslide debris was subject to glacial erosion and was largely removed in the process.[28] About 3 cubic kilometres (0.72 cu mi) of debris is still present;[2] it is found around Tsergo Ri mountain,[1] which is formed by landslide debris and its location is in the central sector of the former landslide.[27] Yala Peak and Dragpoche are in the area of the detachment, east of the seven-thousander Langtang Lirung.[30] The glaciers that had had their valleys cut by the landslide readvanced during the youngest phase of the Würm glaciation and partially restored the valleys. Landslides take place to this day in the area,[31] including during the 2015 Nepal earthquake[15] when a landslide detached from Langtang Lirung peak and killed over 350 people in the Langtang valley.[32] Slow mass movements into valleys[19] and weather/monsoon-controlled mudflows also occur,[33] and there is evidence that the debris from the Tsergo Ri landslide is especially unstable.[34]

Research history edit

Molten rocks formed during the collapse were initially referred to by native people as "yak bones", while early researchers interpreted the rocks as a product of the Himalayan Main Central Thrust fault. In 1984 Heuberger et al. identified their actual origin in a giant landslide.[1] The structure of the landslide body has been mapped using radon emissions and groundwater flows,[18] and the most recent date estimates were obtained with fission track dating on pseudotachylites formed by the collapse.[35]

References edit

  1. ^ a b c d Weidinger & Schramm 1995, p. 231.
  2. ^ a b c Weidinger & Schramm 1995, p. 232.
  3. ^ Weidinger 2001, p. 36.
  4. ^ Ibetsberger 1996, p. 86.
  5. ^ Marston, Miller & Devkota 1998, p. 146.
  6. ^ Weidinger & Schramm 1995, pp. 232, 234.
  7. ^ Weidinger & Schramm 1995, pp. 235–239.
  8. ^ Weidinger 2003, p. 311.
  9. ^ Weidinger & Schramm 1995b, p. 281.
  10. ^ Weidinger & Schramm 1995, p. 239.
  11. ^ Weidinger 2001, p. 38.
  12. ^ Sakai et al. 2016, p. 8.
  13. ^ Dortch et al. 2009, p. 1050.
  14. ^ Weidinger 2003, p. 312.
  15. ^ a b Stumm et al. 2021, p. 3793.
  16. ^ Weidinger 2001, p. 39.
  17. ^ Weidinger & Schramm 1995b, p. 285.
  18. ^ a b c Weidinger & Schramm 1995, p. 235.
  19. ^ a b c Weidinger & Schramm 1995b, p. 287.
  20. ^ Weidinger 2001, p. 40.
  21. ^ Weidinger & Schramm 1995, p. 241.
  22. ^ Weidinger & Schramm 1995, p. 242.
  23. ^ Weidinger 2001, p. 46.
  24. ^ Hewitt, Clague & Orwin 2008, p. 11.
  25. ^ Weidinger & Schramm 1995, p. 234.
  26. ^ Takagi et al. 2007, p. 467.
  27. ^ a b Weidinger & Schramm 1995, p. 240.
  28. ^ a b Stumm et al. 2021, p. 3794.
  29. ^ Takagi et al. 2007, p. 471.
  30. ^ Weidinger 2004, p. 145.
  31. ^ Weidinger & Schramm 1995, p. 240,242.
  32. ^ Dhakal et al. 2020, p. 1844.
  33. ^ Weidinger 2001, p. 53.
  34. ^ Ibetsberger 1996, p. 92.
  35. ^ Tagami 2012, p. 79.

Sources edit

  • Dhakal, Susmita; Cui, Peng; Rijal, Chandra Prasad; Su, Li-jun; Zou, Qiang; Mavrouli, Olga; Wu, Chun-hao (August 2020). "Landslide characteristics and its impact on tourism for two roadside towns along the Kathmandu Kyirong Highway". Journal of Mountain Science. 17 (8): 1840–1859. doi:10.1007/s11629-019-5871-3. S2CID 220656915.
  • Dortch, Jason M.; Owen, Lewis A.; Haneberg, William C.; Caffee, Marc W.; Dietsch, Craig; Kamp, Ulrich (1 June 2009). "Nature and timing of large landslides in the Himalaya and Transhimalaya of northern India". Quaternary Science Reviews. 28 (11): 1037–1054. Bibcode:2009QSRv...28.1037D. doi:10.1016/j.quascirev.2008.05.002. ISSN 0277-3791.
  • Hewitt, Kenneth; Clague, John J.; Orwin, John F. (1 February 2008). "Legacies of catastrophic rock slope failures in mountain landscapes". Earth-Science Reviews. 87 (1): 1–38. Bibcode:2008ESRv...87....1H. doi:10.1016/j.earscirev.2007.10.002. ISSN 0012-8252.
  • Ibetsberger, Horst J. (30 July 1996). "The Tsergo Ri landslide: an uncommon area of high morphological activity in the Langthang valley, Nepal". Tectonophysics. 260 (1): 85–93. Bibcode:1996Tectp.260...85I. doi:10.1016/0040-1951(96)00077-7. ISSN 0040-1951.
  • Marston, R. A.; Miller, M. M.; Devkota, L. P. (1 December 1998). "Geoecology and mass movement in the Manaslu-Ganesh and Langtang-Jugal Himals, Nepal". Geomorphology. 26 (1): 139–150. Bibcode:1998Geomo..26..139M. doi:10.1016/S0169-555X(98)00055-5. ISSN 0169-555X.
  • Sakai, Harutaka; Fujii, Rie; Sugimoto, Misa; Setoguchi, Ryoko; Paudel, Mukunda Raj (27 February 2016). "Two times lowering of lake water at around 48 and 38 ka, caused by possible earthquakes, recorded in the Paleo-Kathmandu lake, central Nepal Himalaya". Earth, Planets and Space. 68 (1): 31. Bibcode:2016EP&S...68...31S. doi:10.1186/s40623-016-0413-5. ISSN 1880-5981. S2CID 34169506.
  • Stumm, Dorothea; Joshi, Sharad Prasad; Gurung, Tika Ram; Silwal, Gunjan (6 August 2021). "Mass balances of Yala and Rikha Samba glaciers, Nepal, from 2000 to 2017". Earth System Science Data. 13 (8): 3791–3818. Bibcode:2021ESSD...13.3791S. doi:10.5194/essd-13-3791-2021. ISSN 1866-3508. S2CID 238808683.
  • Tagami, Takahiro (4 May 2012). "Thermochronological investigation of fault zones". Tectonophysics. 538–540: 67–85. Bibcode:2012Tectp.538...67T. doi:10.1016/j.tecto.2012.01.032. hdl:2433/155980. ISSN 0040-1951.
  • Takagi, Hideo; Arita, Kazunori; Danhara, Tohru; Iwano, Hideki (1 February 2007). "Timing of the Tsergo Ri landslide, Langtang Himal, determined by fission-track dating of pseudotachylyte". Journal of Asian Earth Sciences. 29 (2): 466–472. Bibcode:2007JAESc..29..466T. doi:10.1016/j.jseaes.2005.12.002. ISSN 1367-9120.
  • Weidinger, Johannes T.; Schramm, Josef-Michael (1995). "Tsergo Ri (Langthang Himal, Nepal)–Rekonstruktion der "Paläogeographie" eines gigantischen Bergsturzes" (PDF). Geol. Paläont. Mitt. Innsbruck (in German). 20: 231–243.
  • Weidinger, J. T.; Schramm, J. M. (1995b). "A Short Note on the Tsergo Ri Landslide, Langtang Himal, Nepal". Journal of Nepal Geological Society. 11: 281–287–281–287. doi:10.3126/jngs.v11i0.32803. ISSN 2676-1378.
  • Weidinger, J.T. (2001). Der Tsergo Ri Bergsturz im Nepal Himalaja - Erforschung der größten Kristallinmassenbewegung der Erde als Grundlage für rezente Gefahrenzonenkartierungen (PDF). Geoforum Umhausen (in German). Vol. 2.
  • Weidinger, J.T. (2003). "Die Verwitterung einer Erzstruktur als Ursache für den Einsturz des ehemals 15. Achttausenders im Hohen Himalaya Nepals" (PDF). Mitt. Österr.Miner.Ges. (in German) (148).
  • Weidinger, JOHANNES T. (May 2004). "Das ERKUDOK © Institut im Stadtmuseum Gmunden – Eine geowissenschaftliche Forschungsstätte im Salzkammergut" (PDF). Jahrbuch der Geologischen Bundesanstalt (in German). 144 (1). Vienna: 141–153. ISSN 0016-7800.

January 01, 1970
tsergo, landslide, prehistoric, landslide, nepalese, himalaya, which, took, place, around, years, during, last, glacial, period, during, collapse, mass, rock, about, cubic, kilometres, detached, from, previous, mountain, ridge, descended, with, speed, about, k. The Tsergo Ri landslide was a prehistoric landslide in the Nepalese Himalaya which took place around 51 000 13 000 years ago during the Last Glacial Period During the collapse a mass of rock of about 10 15 cubic kilometres 2 4 3 6 cu mi detached from a previous mountain or ridge and descended with a speed of about 450 kilometres per hour 120 m s later glaciers eroded almost the entire landslide mass Previously weakened rocks may have contributed to the collapse which was probably started by an earthquake Contents 1 Geomorphology and geology 1 1 Causes and trigger 1 2 Pre landslide topography and landslide 1 3 Timing and aftermath 2 Research history 3 References 3 1 SourcesGeomorphology and geology editThe collapse of Tsergo Ri took place in Nepal s Langtang valley 1 perpendicular to the Himalaya 2 and about 60 kilometres 37 mi north of the Nepalese capital Kathmandu 3 The small settlement of Kyangjin Kharka lies at the foot of the landslide deposit 4 With a volume of 10 15 cubic kilometres 2 4 3 6 cu mi 2 it is one of the largest known mass movements on Earth 1 and perhaps the largest known landslide in crystalline bedrock 5 Causes and trigger edit The collapse affected Himalayan gneiss rocks which also contain migmatites and granites they also include older pseudotachylite and ultramylonite rocks both of which can be formed by collapses and which acted as a sliding plane for the Tsergo Ri collapse 6 Rocks formed by deformation intrusions of granite and layers of pyrrhotite ore which are unstable under mechanical load and neotectonic faults may have been weak structures that facilitated the collapse 7 8 The Tsergo Ri region is one of the fastest uplifting parts of the Himalaya 9 The Tsergo Ri landslide was probably triggered by seismic activity 10 perhaps on the Himalayan Main Central Thrust 11 a water level drop in the Paleo Kathmandu Lake took place at the same time and may have been caused by the same earthquake 12 The collapse occurred during a time of increased monsoon strength which may have played a role in the collapse 13 Pre landslide topography and landslide edit Based on reconstructions of the pre landslide topography there may have been a 7 500 8 500 metres 24 600 27 900 ft high 14 15 trilateral mountain in the area 16 or a set of ridges 17 The landslide detached in a southwest west southwest direction 18 with the sliding mass breaking apart into blocks 19 Owing to its fast speed of 450 kilometres per hour 120 m s rocks at the base of the slide melted 20 The landslide impacted other mountains and ridges sometimes destroying them 21 or triggering secondary collapses 19 and may have mixed with glacier ice 22 It was eventually halted by topography such as the flanks of Pangshungtramo mountain 23 before it could become a debris avalanche 24 The landslide debris consists of individual compact blocks on top of a basal breccia 25 and originally may have reached a thickness of 600 800 metres 2 000 2 600 ft 26 Deformed structures inside the collapse debris indicate that small scale movements occurred within the landslide 18 The slide obstructed several glacial valleys 27 Timing and aftermath edit The collapse took place about 51 000 13 000 years ago 28 between two phases of the Wurm glaciation 29 After the collapse landslide debris was subject to glacial erosion and was largely removed in the process 28 About 3 cubic kilometres 0 72 cu mi of debris is still present 2 it is found around Tsergo Ri mountain 1 which is formed by landslide debris and its location is in the central sector of the former landslide 27 Yala Peak and Dragpoche are in the area of the detachment east of the seven thousander Langtang Lirung 30 The glaciers that had had their valleys cut by the landslide readvanced during the youngest phase of the Wurm glaciation and partially restored the valleys Landslides take place to this day in the area 31 including during the 2015 Nepal earthquake 15 when a landslide detached from Langtang Lirung peak and killed over 350 people in the Langtang valley 32 Slow mass movements into valleys 19 and weather monsoon controlled mudflows also occur 33 and there is evidence that the debris from the Tsergo Ri landslide is especially unstable 34 Research history editMolten rocks formed during the collapse were initially referred to by native people as yak bones while early researchers interpreted the rocks as a product of the Himalayan Main Central Thrust fault In 1984 Heuberger et al identified their actual origin in a giant landslide 1 The structure of the landslide body has been mapped using radon emissions and groundwater flows 18 and the most recent date estimates were obtained with fission track dating on pseudotachylites formed by the collapse 35 References edit a b c d Weidinger amp Schramm 1995 p 231 a b c Weidinger amp Schramm 1995 p 232 Weidinger 2001 p 36 Ibetsberger 1996 p 86 Marston Miller amp Devkota 1998 p 146 Weidinger amp Schramm 1995 pp 232 234 Weidinger amp Schramm 1995 pp 235 239 Weidinger 2003 p 311 Weidinger amp Schramm 1995b p 281 Weidinger amp Schramm 1995 p 239 Weidinger 2001 p 38 Sakai et al 2016 p 8 Dortch et al 2009 p 1050 Weidinger 2003 p 312 a b Stumm et al 2021 p 3793 Weidinger 2001 p 39 Weidinger amp Schramm 1995b p 285 a b c Weidinger amp Schramm 1995 p 235 a b c Weidinger amp Schramm 1995b p 287 Weidinger 2001 p 40 Weidinger amp Schramm 1995 p 241 Weidinger amp Schramm 1995 p 242 Weidinger 2001 p 46 Hewitt Clague amp Orwin 2008 p 11 Weidinger amp Schramm 1995 p 234 Takagi et al 2007 p 467 a b Weidinger amp Schramm 1995 p 240 a b Stumm et al 2021 p 3794 Takagi et al 2007 p 471 Weidinger 2004 p 145 Weidinger amp Schramm 1995 p 240 242 Dhakal et al 2020 p 1844 Weidinger 2001 p 53 Ibetsberger 1996 p 92 Tagami 2012 p 79 Sources edit Dhakal Susmita Cui Peng Rijal Chandra Prasad Su Li jun Zou Qiang Mavrouli Olga Wu Chun hao August 2020 Landslide characteristics and its impact on tourism for two roadside towns along the Kathmandu Kyirong Highway Journal of Mountain Science 17 8 1840 1859 doi 10 1007 s11629 019 5871 3 S2CID 220656915 Dortch Jason M Owen Lewis A Haneberg William C Caffee Marc W Dietsch Craig Kamp Ulrich 1 June 2009 Nature and timing of large landslides in the Himalaya and Transhimalaya of northern India Quaternary Science Reviews 28 11 1037 1054 Bibcode 2009QSRv 28 1037D doi 10 1016 j quascirev 2008 05 002 ISSN 0277 3791 Hewitt Kenneth Clague John J Orwin John F 1 February 2008 Legacies of catastrophic rock slope failures in mountain landscapes Earth Science Reviews 87 1 1 38 Bibcode 2008ESRv 87 1H doi 10 1016 j earscirev 2007 10 002 ISSN 0012 8252 Ibetsberger Horst J 30 July 1996 The Tsergo Ri landslide an uncommon area of high morphological activity in the Langthang valley Nepal Tectonophysics 260 1 85 93 Bibcode 1996Tectp 260 85I doi 10 1016 0040 1951 96 00077 7 ISSN 0040 1951 Marston R A Miller M M Devkota L P 1 December 1998 Geoecology and mass movement in the Manaslu Ganesh and Langtang Jugal Himals Nepal Geomorphology 26 1 139 150 Bibcode 1998Geomo 26 139M doi 10 1016 S0169 555X 98 00055 5 ISSN 0169 555X Sakai Harutaka Fujii Rie Sugimoto Misa Setoguchi Ryoko Paudel Mukunda Raj 27 February 2016 Two times lowering of lake water at around 48 and 38 ka caused by possible earthquakes recorded in the Paleo Kathmandu lake central Nepal Himalaya Earth Planets and Space 68 1 31 Bibcode 2016EP amp S 68 31S doi 10 1186 s40623 016 0413 5 ISSN 1880 5981 S2CID 34169506 Stumm Dorothea Joshi Sharad Prasad Gurung Tika Ram Silwal Gunjan 6 August 2021 Mass balances of Yala and Rikha Samba glaciers Nepal from 2000 to 2017 Earth System Science Data 13 8 3791 3818 Bibcode 2021ESSD 13 3791S doi 10 5194 essd 13 3791 2021 ISSN 1866 3508 S2CID 238808683 Tagami Takahiro 4 May 2012 Thermochronological investigation of fault zones Tectonophysics 538 540 67 85 Bibcode 2012Tectp 538 67T doi 10 1016 j tecto 2012 01 032 hdl 2433 155980 ISSN 0040 1951 Takagi Hideo Arita Kazunori Danhara Tohru Iwano Hideki 1 February 2007 Timing of the Tsergo Ri landslide Langtang Himal determined by fission track dating of pseudotachylyte Journal of Asian Earth Sciences 29 2 466 472 Bibcode 2007JAESc 29 466T doi 10 1016 j jseaes 2005 12 002 ISSN 1367 9120 Weidinger Johannes T Schramm Josef Michael 1995 Tsergo Ri Langthang Himal Nepal Rekonstruktion der Palaogeographie eines gigantischen Bergsturzes PDF Geol Palaont Mitt Innsbruck in German 20 231 243 Weidinger J T Schramm J M 1995b A Short Note on the Tsergo Ri Landslide Langtang Himal Nepal Journal of Nepal Geological Society 11 281 287 281 287 doi 10 3126 jngs v11i0 32803 ISSN 2676 1378 Weidinger J T 2001 Der Tsergo Ri Bergsturz im Nepal Himalaja Erforschung der grossten Kristallinmassenbewegung der Erde als Grundlage fur rezente Gefahrenzonenkartierungen PDF Geoforum Umhausen in German Vol 2 Weidinger J T 2003 Die Verwitterung einer Erzstruktur als Ursache fur den Einsturz des ehemals 15 Achttausenders im Hohen Himalaya Nepals PDF Mitt Osterr Miner Ges in German 148 Weidinger JOHANNES T May 2004 Das ERKUDOK c Institut im Stadtmuseum Gmunden Eine geowissenschaftliche Forschungsstatte im Salzkammergut PDF Jahrbuch der Geologischen Bundesanstalt in German 144 1 Vienna 141 153 ISSN 0016 7800 Retrieved from https en wikipedia org w index php title Tsergo Ri landslide amp oldid 1145826797, wikipedia, wiki, book, books, library,

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