GS3 (Mains Answer Writing): Landslides | UPSC Mains: Internal Security & Disaster Management PDF Download

Describe the various causes and the effects of landslides. Mention the important components of the National Landslide Risk Management Strategy.

Introduction

• A landslide is defined as the movement of a mass of rock, debris, or earth down a slope. They are a type of mass wasting, which denotes any downward movement of soil and rock under the direct influence of gravity.
• Slope movement occurs when forces acting downward (mainly due to gravity) exceed the strength of the earth materials that compose the slope. Landslides are caused due to three major factors: geology, morphology, and human activity.
• Geology refers to characteristics of the material. The earth or rock might be weak or fractured, or different layers may have different strengths and stiffness.
• Morphology refers to the structure of the land. For example, slopes that lose their vegetation to fire or drought are more vulnerable to landslides.
• Human activity refers to agriculture and construction which increases the risk of a landslide.
• Landslides can be initiated in slopes already on the verge of movement by rainfall, snowmelt, changes in water level, stream erosion, changes in groundwater, earthquakes, volcanic activity, disturbance by human activities, or any combination of these factors. Earthquake shaking and other factors can also induce landslides underwater.

Different effects of landslides are as follows

• Landslides have been verified to result in destruction of property. If the landslide is significant, it could drain the economy of the region or country. After a landslide, the area affected normally undergoes rehabilitation.
• Infrastructure such as roads, railways, leisure destinations, buildings and communication systems can be decimated by a single landslide.
• Communities living at the foot of hills and mountains are at a greater risk of death by landslides. A substantial landslide carries along huge rocks, heavy debris and heavy soil with it.
• The soil, debris, and rock sliding downhill can find way into rivers and block their natural flow. Many river habitats like fish can die due to interference of natural flow of water.

Important components of National Landslide Risk Management Strategy are as follows

• Generation of User-Friendly Landslide Hazard Maps
• Development of Landslide Monitoring and Early Warning System
• Awareness Programmes
• Capacity Building and Training of Stakeholders
• Preparation of Mountain Zone Regulations & Policies
• Stabilisation and Mitigation of Landslides and Creation of Special Purpose Vehicle (SPV) for Landslide Management.