Understanding the Chandmari Landslides Open image in new window

  • Nirmala VasudevanEmail author
  • Kaushik Ramanathan
  • Aadityan Sridharan
Conference paper


Chandmari Hill lies in Gangtok City in the Himalayan Mountain Ranges of Northeast India. The Himalayas are particularly prone to landslides due to complex geology combined with high tectonic activity, steep slopes, and heavy rainfall. Chandmari Hill has experienced a significant number of landslides, both rainfall and earthquake triggered, during the past several decades. Recently, the Government of India commissioned Amrita University to develop and deploy a landslide early warning system at Chandmari Hill. During the initial phase of the deployment, we conducted walkover surveys at Chandmari Locality, which comprises a large portion of Chandmari Hill. We also extracted and tested soil samples, drilled a 33.5 m borehole, and analyzed rock cores from the borehole. We present the results of laboratory soil tests and use these results in mathematical models. We examine all landslides (rainfall-triggered and earthquake-induced) recorded at Chandmari Locality during the past five decades. Simple calculations demonstrate that when the input parameters of the models mimic the field conditions precursory to an actual landslide, the factor of safety of the slope is less than unity. Gangtok City lies close to the Main Central Thrust, MCT2, which separates the gneissic rocks of the Paro/Lingtse Formation from the mica schists of the Daling Formation. Our field investigations revealed that at Chandmari Locality, gneissic rock overlies highly weathered mica schist. We postulate that surface runoff infiltrates through fractures in the overlying gneiss and results in an extrusion of the finer micaceous material, leading to subsidence which is routinely observed during the monsoon season. During torrential rains, rainwater infiltration causes the sliding of the soft micaceous bands underlying the gneissic rock, leading to rockslides at the hill. We suggest that similar processes are responsible for the frequent and widespread occurrences of landslides and subsidence observed throughout the region.


Landslide Subsidence Chandmari Himalayas Sikkim Gangtok Main Central Thrust (MCT) Slope stability 



We thank Mr. Ranjith N. Sasidharan for helping us prepare the figures for this paper, Dr. H. M. Iyer, Dr. R. Dhandapani, Dr. Sreevalsa Kolathayar, Dr. P. Thambidurai, Dr. Malay Mukul, Dr. Ganesh Khanal, and Mr. Keshar Kumar Luitel for technical discussions, Mr. Kevin Degnan for help with technical writing and painstakingly proofreading the entire manuscript, and Sri P. P. Shrivastav for his support of this work. We thank the session editor, Dr. Jan Klimeš, for reading our original submission with great care and providing insightful comments. The Amrita University landslide projects, aimed at developing wireless sensor network-based landslide early warning systems, are vast, multi-disciplinary efforts. The team is too large for us to name every member; we gratefully acknowledge their help and support. Above all, we express our heartfelt gratitude for the immense guidance and motivation provided by the Chancellor of our University, Sri Mata Amritanandamayi Devi (Amma). This work was funded by the Ministry of Earth Sciences (MoES), Government of India.


  1. Anbarasu K, Sengupta A, Gupta S, Sharma SP (2010) Mechanism of activation of the Lanta Khola landslide in Sikkim Himalayas. Landslides 7(2):135–147CrossRefGoogle Scholar
  2. Arora KR (2003) Soil mechanics and foundation engineering. Standard Publishers Distributors, DelhiGoogle Scholar
  3. Basu SR, De SK (2003) Causes and consequences of landslides in the Darjeeling-Sikkim Himalayas, India. Geographia Polonica 76(2):37–52Google Scholar
  4. 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(4):351–368CrossRefGoogle Scholar
  5. Bhattacharyya K (2010) Geometry and kinematics of the fold-thrust belt and structural evolution of the major Himalayan fault zones in the Darjeeling–Sikkim Himalaya, India. Ph.D. thesis, University of Rochester, Rochester, USAGoogle Scholar
  6. Chakraborty I, Ghosh S, Bhattacharya D, Bora A (2011) Earthquake induced landslides in the Sikkim-Darjeeling Himalayas—an aftermath of the 18th September 2011 Sikkim earthquake. Geological Survey of India, KolkataGoogle Scholar
  7. Dubey CS, Chaudhry M, Sharma BK, Pandey AC, Singh B (2005) Visualization of 3-D digital elevation model for landslide assessment and prediction in mountainous terrain: a case study of Chandmari landslide, Sikkim, Eastern Himalayas. Geosci J 9(4):363–373CrossRefGoogle Scholar
  8. Duncan JM, Buchignani AL, De Wet M (1987) An engineering manual for slope stability studies. Virginia Polytechnic Institute and State University, BlacksburgGoogle Scholar
  9. Ghoshal TB, Sringanengam S, Sengupta CK (1998) Detailed investigation of Chandmari Landslide near Gangtok. Geological Survey of India, KolkataGoogle Scholar
  10. Gupta H, Gahalaut VK (2014) Seismotectonics and large earthquake generation in the Himalayan region. Gondwana Res 25(1):204–213CrossRefGoogle Scholar
  11. Iverson RM (2000) Landslide triggering by rain infiltration. Water Resour Res 36(7):1897–1910CrossRefGoogle Scholar
  12. James N, Sitharam TG (2015) Macro-level assessment of seismically induced landslide hazard for the State of Sikkim, India based on GIS technique. In: IOP Conference series: Earth and Environmental Science 26(1):012027. IOP PublishingCrossRefGoogle Scholar
  13. Kanth S R, Iyengar R N (2007) Estimation of seismic spectral acceleration in peninsular India. Journal of Earth System Science. 116(3)Google Scholar
  14. Newmark NM (1965) Effects of earthquakes on dams and embankments. Geotechnique 15(2):139–160CrossRefGoogle Scholar
  15. Ramesh MV, Vasudevan N (2012) The deployment of deep-earth sensor probes for landslide detection. Landslides 9(4):457–474Google Scholar
  16. Rawat RK (2005) Geotechnical investigations of Chandmari landslide located on Gangtok-Nathula road, Sikkim Himalaya, India. J Himalayan Geol 26(2):309–322Google Scholar
  17. Reuters (1997) Landslides claim at least 28 in India. CNN. 9 June 1997. Last accessed 7 Sept 2016
  18. Roy S, Baruah A, Misra S, Mandal N (2015) Effects of bedrock anisotropy on hillslope failure in the Darjeeling-Sikkim Himalaya: an insight from physical and numerical models. Landslides 12(5):927–941CrossRefGoogle Scholar
  19. Sharma AK (2008) Landslide and its mitigation for disaster management using remote sensing and GIS technique-a case study of Gangtok area, East Sikkim. MSc thesis Sikkim Manipal University of Health, Medical and Technological sciences, Gangtok, IndiaGoogle Scholar
  20. Sharma ML, Douglas J, Bungum H, Kotadia J (2009) Ground-motion prediction equations based on data from the Himalayan and Zagros regions. J Earthquake Eng 13(8):1191–1210CrossRefGoogle Scholar
  21. SikkimNow (2011) Around Gangtok, 19 Sept 2011. Last accessed 9 Sept 2016
  22. The Sikkim Times (2011) Heavy rains trigger landslides across Gangtok. Last accessed 14 Sept 2016
  23. Vasudevan N, Ramanathan K (2016) Geological factors contributing to landslides: case studies of a few landslides in different regions of India. In: Institute of Physics Conference Series: Earth and Environmental Science. 30(1):012011-012016. IOP PublishingCrossRefGoogle Scholar
  24. Vasudevan N, Kolathayar S, Sridharan A, Ramanathan K (2016) An investigative study of seismic landslide hazards. In: Proceedings of the international conference on recent advances in rock engineering (RARE-2016), 16–18 November 2016, Bengaluru, India, pp 195–204Google Scholar

Copyright information

© Springer International Publishing AG 2017

Authors and Affiliations

  • Nirmala Vasudevan
    • 1
    Email author
  • Kaushik Ramanathan
    • 2
  • Aadityan Sridharan
    • 3
  1. 1.Amrita Center for Wireless Networks and Applications, Amrita School of Engineering, Department of Physics, Amrita School of Arts and SciencesAmrita Vishwa Vidyapeetham, Amrita UniversityAmritapuriIndia
  2. 2.Department of Civil Engineering, Amrita School of EngineeringAmrita Vishwa Vidyapeetham, Amrita UniversityCoimbatoreIndia
  3. 3.Deparment of Physics, Amrita School of Arts and SciencesAmrita Vishwa Vidyapeetham, Amrita UniversityAmritapuriIndia

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