Landslides, Landslide Prone Areas of India, Earthquake, High Risk Earthquake Prone Areas of India

Doorsteptutor material for IAS/Mains/Optional Public-Administration is prepared by world's top subject experts: Get detailed illustrated notes covering entire syllabus: point-by-point for high retention.

Download PDF of This Page (Size: 375K)

Landslides

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 Hazard Zones of India

Landslide Hazard Zones of India

Landslide Prone Areas of India

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

Causes of Landslides

  • Heavy Rain: Heavy rain is the main cause of landslides.

  • Deforestation: Tree, brushes and grasses keep the soil particles compact. Mountain slope loses their protective cover by felling of trees. The rainwater flows on such slopes with unimpeded speed causes landslides.

  • Earthquakes and Volcanic Explosions: Earthquake is a common feature in the Himalaya. Tremors destabilize the mountains and the rocks tumble downwards. Volcanic explosions also trigger landslides in the mountainous areas.

  • 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.

  • Shifting Agriculture: In the north-eastern part of India, the number and frequency of landslides has increased due to the practice of shifting cultivation.

  • 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 is created. This causes the landslides.

Impact of Landslide

  • Landslides are degrading the environment and natural beauty of the mountains.

  • Sources of water are drying up.

  • Flooding in rivers is increasing.

  • Roads are blocked.

  • Life and property are lost.

Measures to Control Landslides and to Mitigate Their Impact

  • Trees and brushes help in binding the soil particles.

  • Roads should be constructed in such a way, that lesser amount of debris is generated.

  • Ban on quarrying of stones and mining of minerals.

  • Permanent crops like orchards of fruits should replace the seasonal or annual crops.

  • By controlling the surface flow of water, seepage of water should be minimised.

  • Retaining walls can be built of mountain slopes to stop land from slipping.

  • Hazard mapping should be done to locate areas commonly prone to landslides.

  • Building and construction activities may be banned in such areas.

Earthquake

In simple words sudden shaking or trembling of the earth’s surface is an earthquake. Most earthquakes are a minor tremor. Larger earthquakes usually begin with slight tremors but suddenly they turn into violent shocks and after that the intensity of shocks diminishes. Earthquake can occur at any time of the year, day or night. Its impact is very sudden. There are no warning signs of earthquakes. Extensive and sincere research has been conducted but success has eluded humans in the forecast or prediction of earthquake.

High Risk Earthquake Prone Areas of India

Bureau of Indian Standard has prepared a map of India, showing earthquake seismic zones of different intensity. Its revised edition has been published in 2002. India has been divided into four zones.

  • Zone I- The earthquake is very feeble and have slight to moderate intensity.

  • Zone II- The earthquake is felt by all, some people run outdoor. Heavy furniture may possibly move little small pieces of plaster fall. Cracks in chimneys are found.

  • Zone III- Everyone runs out of doors; slight damage is there even in better designed and strongly built building. Considerable damage to poorly designed and sub-standard buildings bridges.

  • Zone IV- Slight damage in specially designed and well-built building bridges. Heavy damage to poorly designed and badly built structures. Chimneys, poles, memorials, and walls fall down.

  • Zone V- Severe damage to even well-built bridges, buildings, and foundations are displaced. Cracks and fissures develop in the ground. Practically all structures fall or small are greatly damaged or destroyed.

Seismic Zones of India

Image of Seismic Zones of India

Delhi and Mumbai are situated in high risk zone no. IV. The whole of North East India, Kachchh, Gujarat, Uttarakhand, Himachal Pradesh, and Jammu and Kashmir are in the very high-risk zone no. V. Now peninsular plateau is not safe from earthquakes. Earthquake of Latur in 1993, intensity of 6.4 on Richter scale and Koyna in 1967, intensity of 6.5 in Maharashtra testify it.

Developed by: