Vulnerability to Landslide
Landslides are a common geomorphic hazard in Himalayan states which is generally triggered by heavy rainfall almost every year and also often by major earthquakes in this active Himalayan Fold-Thrust-Belt. Available landslide susceptibility and inventory maps along important pilgrimage routes, road-corridors, river basins and site-specific large scale (1:2000 or larger) landslide maps have already revealed that within these Himalayan states, parts of many mountainous tracts and locations are highly vulnerable and susceptible to landslides.
The highly unstable zones studied by Geological Survey of India (GSI) in various zones are given in Annexure-I.
GSI has launched a project to create a landslide compendium for north western Himalayas. The project started on 1 April, 2014. The details of project outcome are given below.
- The compendium includes all major landslide studies carried out by GSI till 2013 in the North West (NW) Himalayas in the States of Uttarakhand, Himachal Pradesh and Jammu & Kashmir.
- The type of information included in the compendium are (i) Landslide Susceptibility Maps on scale 1:50,000 covering parts of river basins such as Ramganga, Ganga, Yamuna, Bhagirathi, Sutlej, Beas, Ravi, Chenab river basin etc; (ii) Landslide Susceptibility Maps on scale 1:50,000/25,000/10,000 covering major towns such as Pithoragarh, Bageshwar, Joshimath, Vaishno Devi, Ranikhet, Shimla etc; (iii) Landslide Susceptibility Maps on scale 1:50,000 covering important pilgrimage road corridors such as Yamunotri yatra route, Gangotri yatra route, Kedarnath-Badrinath yatra route, Kailash-Mansarovar yatra route, Harkidun road, Narkanda-Rampur-Khab Road, Kangra-Dharmshala-Sihunta-Dalhousie Road, Kalka-Shimla Narrow Gauge Railway Route, Arakot-Rohru-Narkanda-Theog-Chail-Solan Road etc.; (iv) site specific landslide investigations including detailed geological maps; (v) post disaster reconnoitary geological assessment of major landslide events including the recent 2013 Uttarakhand Disaster; and (vi) inventory of major landslides in a tabular form.
National Disaster Management Authority (NDMA) has published guidelines on Landslides and Snow Avalanches on its website. Following are the precautionary measures for landslides that are under wide circulation though print and visual media:
Prepare tour to hilly region according to information given by weather department or news channel.
- Minimize movement around landslide path ways during rainy days or downstream valleys having past history of landslides.
- Keep drains clean,
- Inspect drains for – litter, leaves, plastic bags, rubble etc.
- Keep the weep holes open.
- Grow more trees that can hold the soil through roots and their by minimizing erosions.
- Identify areas of rock fall and subsidence of buildings, cracks that indicate landslides and move to safer areas. Even muddy river waters indicate landslides upstream.
- Notice such signals and contact the nearest Tehsil or District Head Quarters.
- Ensure that toe of slope is not cut, remains protected, don’t uproot trees unless re-vegetation is planned.
- Listen for unusual sounds such as trees cracking or boulders knocking together.
- Stay alert, awake and active (3A’s) during the impact or probability of impact and locate safe shelters
This was stated by Minister of State for Ministry of Science & Technology and Earth Sciences, Shri Y.S. Chowdary in a written reply to a Question in Lok Sabha on 27th July, 2016.