Q) “The Himalayas are highly prone to landslides.” Discuss the causes and suggest suitable measures of mitigation?
What is a Landslide:
What is a Landslide:
A landslide is defined as the movement of a mass of rock, debris, or earth down a slope. Landslides are a type of “mass wasting,” which denotes any down-slope movement of soil and rock under the direct influence of gravity.
Almost every landslide has multiple causes. Landslides can be initiated in slopes already on the verge of movement by rainfall, snowmelt, changes in water level, stream erosion, changes in ground water, earthquakes, volcanic activity, disturbance by human activities, or any combination of these factors.
Himalayan region is situated at the confluence of the Indian plate in south and the Eurasian plate in North and hence it is highly geodynamic. This instability throughout the year, coupled with anthropogenic factors, makes it prone to landslides which are large scale hazardous movement of rock and debris down the slope of a mountain.
Himalayan landslides can be attributed to the fact that Himalayas lies at the convergence zone of two lithospheric plates, i.e., Indian plate in the south and Eurasian plate in the north. Thus geologically, it is considered very active.
Himalayan regions are prone to frequent earthquakes leading to loosening of soils that further leads to landslides.
Himalayas haven’t yet reached its isostatic equilibrium and hence under constant influence of earthquake which can trigger landslides.
Himalayas are mainly composed of sedimentary rocks which can get disturbed under slightest of stress and slide down.
Himalayas are loftier than other mountain ranges and have greater slope due to which soil once loosened, triggers a full blown land or mud slide.
Himalayas have numerous rivers and streams which can carry large amount of debris with them. Sometimes they loosen up big boulders and parts of mountains and bring them down with themselves.
Himalayas have large amount of snow which can become unstable due to heat from sun and trigger landslides (avalanches).
Construction activities like road and tunnel construction not only loosens the soil, but they also require blasting due to which the mountains become really fragile and prone to landslides.
Global warming has led to quicker melting of snow and more percolation of water within the underlying surface of hill.
Inappropriate agricultural practices like shifting or jhum cultivation, which require clearing of forests for agriculture, makes top soil prone to movement by removing the trees which bind them.
Himalayas being source of many rivers has lead to construction of multipurpose dam projects which has affected the already fragile Himalayas.
Himalayan region is centre of huge diversity when it comes to trees & this diversity has led to discriminate chopping of trees leading to soil erosion which in turn leads to Landslides.
Illegal mining & Industrial activities too have contributed a lot when it comes to reasons of landslides in the region.
A vulnerability mapping to have advance preparedness along with integrated efforts to it through LSZ mapping
Identifying Eco Sensitive Zones and enforcing appropriate legislations.
Limiting the construction activities and using equipment or technology that do not increase the stress.
Building catchment areas to capture extra rainfall water.
Afforestation, controlled grazing and scientific capacity increasing to top soil cover.
Constructing Engineered Structures for the preventing soil erosion and in turn landslides.
Mock drills towards evacuation during landslides in the highly vulnerable areas to minimize loss of life.
Spreading awareness towards the causes,vulnerable areas and training the steps for evacuation at both individual and community level through specific camps and campaigns. Including third party like NGO;s for the same.
Constructing a permanent assessment team comprising scientists & geologists that would look into the matter.
An integrated and dedicated tri pronged approach towards improving advance preparedness, limiting the stress factors and early evacuation through community, state and central participation can be substantial in reducing the effects of landslides in Himalayan region.