Landslides


A major landslide occurred in the midnight in a place called Lamari on the foot path leading to Kailash Mansarovar about 60 km away from Dharchula, in August 1998. Lamari is situated between Bendi and Malpa. The debris of this landslide slipped into river Kali and blocked its flow. The water of the river spread over an area of 1½ square km. Thus a lake was created in which the water was flowing. Some pilgrims going to Kailash Mansarovar were resting here in this fateful night. This landslide killed 60 pilgrims.

What is a Landslide?

The slipping of masses of rocks, earth or debris downwards on the mountain slopes or banks of the rivers is called a landslide. The occurrence of landslides in mountainous areas is increasing day by day. The impact of landslides on the people in the mountains is clearly visible.

Landslide prone areas

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The landslides are a common feature in Himalayas, Western ghats and in river valleys. The state of Jammu & Kashmir, Himachal Pradesh, Uttarakhand, Sikkim and all the seven states of North East India, are most vulnerable to landslide. In southern India Maharashtra, Karnataka, Tamil Nadu and Kerala bear the brunt of landslides.

Causes of landslides

  1. Heavy rain : Heavy rain is the main cause of landslides.
  2. Deforestation : Deforestation is another major cause of landslides. Tree, brushes and grasses keep the soil particles compact. Mountain slope looses their protective cover by felling of trees. The rain water flows on such slopes with unimpeded speed.
  3. Earthquakes and volcanic explosions : Earthquake is a common feature in the Himalayas. Tremors destabilize the mountains and the rocks tumble downwards. Volcanic explosions also trigger landslides in the mountainous areas.
  4. Building of roads : Roads are built in mountainous areas for development. During the process of the construction of road, a large amount of rocks and debris has to be removed. This process dislodges the rock structure and changes the angle of slopes. Consequently landslides are triggered.
  5. Shifting agriculture : In the North Eastern part of India, the number and frequency of landslides has increased due to the practice of shifting agriculture.
  6. Construction of houses and other buildings : For giving shelter to the ever-increasing population and promotion of tourism more and more house and hotels are being built. In building processes large amount of debris created. This causes the landslides.

Impact of landslides

  • (i) Degrading of environment : Landslides are degrading the environment of mountains. Natural beauty is diminishing slowly and slowly.
  • (ii) Sources of water are drying up.
  • (iii) Flooding in rivers is increasing.
  • (iv) Roads are blocked.
  • (v) Life and property are lost.

Measures to control landslides and to mitigate their impact

  • (i) Afforestation : Trees and brushes help in binding the soil particles.
  • (ii) New technology in road construction : Roads should be constructed in such a way, that lesser amount of debris are generated.
  • (iii) Ban on quarrying of stones and mining of minerals.
  • (iv) Instead of exploitation of forests, they should be used scientifically.
  • (v) Permanent crops like orchards of fruits should replace the seasonal or annual Drops.
  • (vi) By controlling the surface flow of water, seepage of water should be minimised.
  • (vii) Retaining walls can be built of mountain slopes to stop land from slipping.
  • (viii) Hazard mapping should be done to locate areas commonly prone to landslides. Building and construction activities may be banned in such areas.

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The slipping of masses of rocks, earth or debris downwards on the mountain slopes or banks of rivers is called a landslide.
During rainy season landslides are a common feature in Himalayas, Western Ghat and deep river valleys.

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Bibliography : NIOS Geography Book

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