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Macroseismic field observations of 18 September 2011 Sikkim earthquake

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Abstract

A shallow-focus damaging earthquake of magnitude 6.9 Mw struck the Sikkim Himalaya, north-east India, on 18 September 2011 at 12:40:48 UTC (06:10:48PM IST). The epicentre was located north-west of Chungthang on Indo-Nepal border of Sikkim Himalaya. The earthquake was widely felt in northern India and caused widespread damage to poorly built and framed structures in Sikkim region, northern Bihar, eastern Nepal, southern Bhutan and part of Tibet adjoining Sikkim Himalaya. A lot of secondary effects in the form of landslides, rockfalls and landslide lake outburst flood were caused due to strong shaking effect of the earthquake. Maximum intensity IX according to the European Macroseismic Scale-98 was observed in the meizoseismal zone surrounding Chungthang village. Asymmetrical distribution and heterogeneous damage pattern demonstrate intensity attenuation characteristics of the region. Although the regional tectonic framework of Sikkim region indicates compressional thrust tectonics regime, according to CMT fault-plane solution this earthquake involved predominantly strike-slip motion on a steep fault. Unlike Nepal and north-west Himalaya where microseismicity and large earthquakes indicate thrust mechanism, this Sikkim earthquake suggests that strike-slip principal component may imply transcurrent deformation.

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References

  • Bakun WH, Wentworth CM (1997) Estimating earthquake location and magnitude from seismic intensity data. Bull Seism Soc Am 87(6):1502–1521

    Google Scholar 

  • Bhasin R, Grimstad E, Larsen JO, Dhawan AK, Singh R, Verma SK, Venkatachalam K (2002) Landslide Hazards and mitigation measures at Gangtok, Sikkim Himalaya. Eng Geol 64:351–368

    Article  Google Scholar 

  • Bilham R, Wallace K (2005) Future Mw > 8 earthquakes in the Himalaya: implications from the 26th December 2004 Mw + 9.0 earthquake on India’s eastern plate margin. Geol Surv India Spec Publ 85:1–14

    Google Scholar 

  • BIS Code 1893 (2002) Earthquake hazard zoning map of India. http://www.bis.org.in

  • De R (2000) A microearthquake survey at the MBT zone: Sikkim Himalaya. J Geophys 22:77–84

    Google Scholar 

  • De R, Kayal JR (2003) Seismotectonic model of the Sikkim Himalaya: constraint from microearthquake surveys. Bull Seism Soc Am 93(3):1395–1400

    Article  Google Scholar 

  • De R, Kayal JR (2004) Seismic activity at the MCT in Sikkim Himalaya. Tectonophysics 386:243–248

    Article  Google Scholar 

  • de La Torre TL, Monsalve AF, Sheehan S, Sapkota S, Wu F (2007) Earthquake processes of the Himalaya collision zone in eastern Nepal and southern Tibet plateau. Geophys J Int 171:178–738

    Google Scholar 

  • De R, Saha DK, Chakraborty P (1995). A microearthquake survey in the Himalayan foredeep region, north Bengal area, Unoub. Geol Surv India Report

  • Drukpa D, Velasco AA, Doser DI (2006) Seismicity in the Kingdom of Bhutan (1937–2003): evidences for crustal transcurrent deformation. J Geophys Res 111, B06301:1–14

    Google Scholar 

  • Evernden JF (1975) Seismic intensities, “size” of earthquakes and related parameters. Bull Seism Soc Am 65:1287–1313

    Google Scholar 

  • Grünthal G (1998) European macroseismic scale 1998 (EMS-98). Cashiers de centre Européen de Geodynamique et de Sesimologie 15:99

  • GSI (1993) The Bihar-Nepal earthquake of 1934. Mem Geol Surv India 73:287–288

    Google Scholar 

  • Hanks TC, Hileman JA, Thatcher W (1975) Seismic moments of the larger earthquakes of the southern California region. Geol Soc Am Bull 86:1131–1139

    Article  Google Scholar 

  • Hazarika P, Kumar MR, Srijayanthi G, Raju PS, Rao NP, Srinagesh D (2010) Transverse tectonics in the Sikkim Himalaya: evidence from seismicity and focal mechanism data. Bull Seism Soc Am 100:1816–1822

    Article  Google Scholar 

  • Jounne F, Mugnier JL, Gamond JF, Le Fort P, Serrurier L, Flouzat M, Avouac J (2004) Current shortening across the Himalayas of Nepal. Geophys J Int 157:1–14

    Article  Google Scholar 

  • Kumar S, Mahajan AK (1993) The Uttarkashi earthquake of 20th October, 1991: field observations. Terra Nova 6(2):95–99

    Google Scholar 

  • Kumar S, Wesnousky SG, Jayangondaperumal R, Nakata T, Kumhara Singh V (2010) Palaeoseismological evidence of surface faulting along the northern Himalayan front, India: timing, size and spaded extent of great earthquake. J Geophys Res 115:B12422. doi:1029

    Article  Google Scholar 

  • Mahajan AK, Virdi NS (2001) Macroseismic field generated by the 29th March Chamoli Earthquake, 1999 and its seismotectonics. J Asian Earth Sci 19(4):507–516

    Article  Google Scholar 

  • Monsalve G, Sheehan A, Schulate-Pelkum V, Rafaure S, Pandey MR, Wu F (2006) Seismicity and one dimensional velocity structure of the Himalayan collision zone: earthquake in the crust and upper mantle. J Geophys Res 111, B10301:1–19

    Google Scholar 

  • Nath SK (2004) Seismic hazard and microzonation in the Sikkim Himalaya through GIS integration of site effects and strong motion attributes. Nat Hazard 31:319–342

    Article  Google Scholar 

  • Ni J, Barazangi M (1984) Seismotectonics of the Himalayan collision zone: geometry of the under thrusting Indian plate beneath the Himalaya. J Geophys Res 89:1147–1163

    Article  Google Scholar 

  • Ray SK (2000) Culmination zones in Eastern Himalaya. Geol Surv India Spec Publ 55:85–94

    Google Scholar 

  • Thakur VC, Mahajan AK, Gupta V (2012) Seismotectonics of 18 September 2011 Sikkim earthquake: a component of transcurrent deformation in eastern Himalaya. Him Geol 33(1):89–96

    Google Scholar 

  • Verma PN (1993) Geotechnical report on September, 1983 Landslide in North Sikkim. Geol Surv India (unpublished) Rep 1983–1984, FS

Download references

Acknowledgments

The authors thank Prof. Anil Kumar Gupta, Director, Wadia Institute of Himalayan Geology, Dehra Dun, for supporting the field investigation immediately after the occurrence of earthquake, as well as his constant encouragement to publish the results of the study. The authors thank Sikkim state administration especially District Magistrate, Mangan, North Sikkim, Sub-Divisional Magistrate, Chungthang, Army Unit at Chungthang, and Managing Director, Tista Urja, and Pawan Hans authorities for providing Heli facility to visit north Sikkim earthquake-affected region.

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Correspondence to A. K. Mahajan.

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Mahajan, A.K., Gupta, V. & Thakur, V.C. Macroseismic field observations of 18 September 2011 Sikkim earthquake. Nat Hazards 63, 589–603 (2012). https://doi.org/10.1007/s11069-012-0170-0

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