This report presents information about the status of landslides in Sikkim. It was commissioned by the Department of Science and Technology and authored by the Wadia Institute of Geology. It draws upon several archives including that of the Directorate of Geology and Mining, Government of Sikkim. The report also presents recommendations for preparing an action plan for undertaking landslide studies.
It speaks of the necessity for coordination and information exchange between the various institutions working on landslides, especially between central and state agencies.The authors also describe the necessity for large-scale mapping of landslides.
Sikkim's rugged topography, especially the altitudinal variations (from 200 to 7000 metres above sea level) has led to a large range of climate conditions. This chapter presents rainfall data for 18 stations in Sikkim. An isohytal map of the state is also presented. The authors observe that the maximum incidence of landslides occur in high-rainfall zones. not only that, but the incidence of landslides can be correlated to daily rainfall.
The tectono-stratigraphic succession of rocks of Sikkim is presented in a table which also details the districts in which the rocks are exposed.
This chapter also introduces the topic of natural hazards in Sikkim. It explains that regions with the presence of schists and phyllites are most susceptible to landslides due to their susceptibility to weathering, shear distortion and mineral structure. The authors discuss the periodicity, mode of generation, and history of earthquakes in the area. These earthquakes trigger landslides both directly and when they cause seismic deformations which become weak zones.
In addition to the original document which you can download below in pdf format, this article also presents the above information in two additional formats. Certain parameters are presented in a spreadsheet which can be downloaded below, and the landslides for which latitude and longitude are available have been mapped below.