Estimation of Rainfall-Induced Landslides Using the TRIGRS Model
- 48 Downloads
Rainfall-induced landslides have become the biggest threat in the Indian Himalayas and their increasing frequency has led to serious calamities. Several models have been built using various rainfall characteristics to determine the minimum rainfall amount for landslide occurrences. The utilisation of such models depends on the quality of available landslide and rainfall data. However, these models do not consider the effect of local soil, geology, hydrology and topography, which varies spatially. This study is to analyse the triggering process for shallow landslides using physical-based models for the Indian Himalayan region. This research focuses on the utilisation and dependability of physical models in the Kalimpong area of Darjeeling Himalayas, India. The approach utilised the transient rainfall infiltration and grid-based regional slope-stability (TRIGRS) model, which is a widely used model in assessing the variations in pore water pressure and determining the change in the factor of safety. TRIGRS uses an infinite slope model to calculate the change in the factor of safety for every pixel. Moreover, TRIGRS is used to compare historical rainfall scenarios with available landslide database. This study selected the rainfall event from 30th June to 1st July 2015 as input for calibration because the amount of rainfall in this period was higher than the monthly average and caused 18 landslides. TRIGRS depicted variations in the factor of safety with duration before, during and after the heavy rainfall event in 2015. This study further analysed the landslide event and evaluated the predictive capability using receiver operating characteristics. The model was able to successfully predict 71.65% of stable pixels after the landslide event, however, the availability of more datasets such as hourly rainfall, accurate time of landslide event would further improve the results. The results from this study could be replicated and used in other unstable Indian Himalayan regions to establish an operational landslide early warning system.
KeywordsShallow landslides Physical models GIS Rainfall threshold Kalimpong
This research was supported by the Department of Science & Technology (DST), New Delhi, with Grant no. NRDMS/02/31/015(G). We are also thankful to Mr. Praful Rao, President, Save The Hills, Kalimpong for logistical support during field visit. The authors acknowledge the two anonymous reviewers for their useful comments and suggestions.
- Baum RL, Savage WZ, Godt JW (2002) TRIGRS—a Fortran program for transient rainfall infiltration and grid-based regional slope-stability analysis, US Geological Survey, Open-File Report 02-424Google Scholar
- Baum RL, Savage WZ, Godt JW (2008) TRIGRS—a Fortran program for transient rainfall infiltration and grid-based regional slope-stability analysis, version 2.0, US Geological Survey, Open-File Report 2008-1159Google Scholar
- Chatterjee R (2010) Landslide hazard zonation mapping of Kalimpong. VDM Verlag Dr. Muller GmbH & Co, CologneGoogle Scholar
- Cruden DM, Varnes DJ (1996) Landslide types and processes. In: Turner AK, Schuster RL (eds) Landslides: investigation and mitigation. Transportation Research Board special report 247. National Academy Press, Washington DC, pp 36–75Google Scholar
- Ghosh S, Ghoshal TB, Mukherjee S, Bhowmik S (2016) Landslide compendium on Darjeeling-Sikkim Himalayas, India. In: Geological Survey of India. GSI, India (ISSN0 254-0436)Google Scholar
- Ghoshal TB, Sarkar NK, Ghosh S, Surendranath M (2008) GIS based landslide susceptibility mapping-a study from Darjeeling-Kalimpong area, Eastern Himalaya, India. J Geol Soc India 72:763–773Google Scholar
- Mukherjee A, Mitra AK (2001) Geotechnical study of mass movements along the Kalimpong approach road in the Eastern Himalayas. Indian J Geol 73(4):271–279Google Scholar
- Rao P (2009) Landslide hazard case study: the dire need for a comprehensive, long term solution to the landslide problem at Chibo—Pashyor villages, Kalimpong, District Darjeeling, W Bengal. Proceedings of Second India Disaster Management Congress, DelhiGoogle Scholar
- Šimůnek J, Huang M, Šejna M, van Genuchten M (1998) The HYDRUS-1D software package for simulating the one dimensional movement of water, heat, and multiple solutes in variably-saturated media. Version 1.0, International Ground Water Modeling Center, Colorado School of Mines, Golden, ColoradoGoogle Scholar
- Surendranath M, Ghosh S, Ghoshal TB, Rajendran N (2008) Landslide hazard zonation in darjeeling Himalayas: a case study on integration of IRS and SRTM data. In: Nayak S, Zlatanova S (eds) Remote sensing and GIS technologies for monitoring and prediction of disasters. Environmental science and engineering (environmental science). Springer, BerlinGoogle Scholar