LANDSLIDES IN HIMALAYAS

Landslides are mass movement of soil or rocks along the slopes of mountains .The Himalayas are highly prone to landslides, leading to heavy loss of both life & property.

Causes

Landslides occur frequently in the Himalayan region because of the following causes-

A . Natural 

(1) Earthquakes:-Geographical location of Himalayas at the confluence of two lithospheric plates , the Eurasian and Indian plate and hence geologically very active nature . Himalayan regions are prone to frequent earthquakes leading to loosening of soils that further leads to landslides. Construction of numerous hydroelectric project dams induce the causing of earthquakes too.

(2) Rainfall:- Himalayan region receives quite heavy rainfall that leads to soil erosion & landslides.Rainfall decreases the stability of soil and rocks and reduces friction for it to fall more easily. This lubrication effect is accentuated during cloud burts which occurs frequently in the Himalayan region due to its topography.

(3) Slope:-The southern slope of himalayas are very steep compared to its northern slope forming a hog back shape. The steep gradient renders the region prone to landslides .

(4) Thrusts – There are several big thrusts, viz., Main Boundary Thrust (MBT), Main Central Thrust (MCT), Almora Thrust, Vaikrita Thrust, Krol Nappe, Chail Nappe, etc., dividing Himalayas into number of fragments . Presence of large number of faults and lineaments make the region geologically very fragile and susceptible to landslides at any scale.

B . Anthropogenic 

(1) Jhum Cultivation- popularly known as slice & burn type of cultivation practiced particularly in the Himalayan region.

(2) Cutting of trees- Himalayan region is centre of huge diversity when it comes to trees & this diversity has led to indiscriminate cutting of trees.

(3) Illegal mining & Industrial activities –They too have contributed a lot when it comes to reasons of landslides in the region.

(4) Construction of roads using blasting technique and dams .

(5) Himalayas are known for a number of pilgrim sites. They have driven unsustainable tourism development in the region cutting into the mountains leaving them prone to landslides.

Mitigation:

1 . Slopes need to be stabilized with re-forestation of native trees.
2 . Landuse need to be regulated and practices of sustainable development needs to be adopted
3 . Artificial triggering of landslides after extensive study of the slope stability of the region to avert any disaster.
4 . Human induced earthquakes needs to be reduced by not adopting larger dam projects.