Land Slides

What is a Landslide?

Landslides are among the many natural disasters causing massive destructions and loss of lives across the globe. A landslide, sometimes known as landslip, slope failure or slump, is an uncontrollable downhill flow of rock, earth, debris or the combination of the three. When the ground becomes saturated, it can become unstable, losing its equilibrium in the long run. That’s when a landslide breaks loose.

Causes of Landslides:

Landslides are considered naturally occurring disasters, human-induced changes in the environment have recently caused their upsurge. Although the causes of landslides are wide ranging, they have 2 aspects in common; they are driven by forces of gravity and result from failure of soil and rock materials that constitute the hill slope.

Natural Causes of Landslides:

• 1. Climate

• 2. Earthquake

• 3. Weathering

• 4. Erosion

• 5. Volcanoes

• 6. Forest-fire

• 7. Gravity

Human causes of landslides

1. Mining

2. Clearcutting

Effects of Landslide

1. Lead to economic decline

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.

2. Decimation of infrastructure

The force flow of mud, debris, and rocks as a result of a landslide can cause serious damage to property. Infrastructure such as roads, railways, leisure destinations, buildings and communication systems can be decimated by a single landslide.

3. Loss of life

Communities living at the foot of hills and mountains are at a greater risk of death by landslides.

4. Affects beauty of landscapes

The erosion left behind by landslides leaves behind rugged landscapes that are unsightly.

Types of Landslide

1.Falls

Falls are sudden movements of loads of soil, debris, and rock that break away from slopes and cliffs.

2.Slides

This is a kind of mass movement whereby the sliding material breakaways from underlying stable material.

3.Topples

Topple landslides occur when the topple fails.

4.Spreads

They are commonly known as lateral spreads and takes place on gentle terrains via lateral extension followed by tensile fractures.

5.Flows

This type of landslide is categorized into five; earth flows, debris avalanche, debris flow, mudflows, and creep, which include seasonal, continuous and progressive.

CHARACTERISTICS OF LANDSLIDES:

These are sudden failures of vertical or near-vertical slopes that result in the loosening and free fall of a block or several blocks of rock.

LANDSLIDES PRONE AREAS IN INDIA:

Landslides are among the major hydro-geological hazards that affect large parts of India besides the Himalayas, the North-eastern hill ranges, the Western Ghats, the Nilgiris, the Eastern Ghats and the Vindhyans, in that order, covering about 15 % of the landmass. The North-eastern region is badly affected by landslide problems of a bewildering variety.

STEPS TAKEN BY GOVERNMENT TO PREVENT LANDSLIDES:

• 1.construction of retention walls have been done in order to prevent land slides.

• 2.set up of physical barriers like sand sac

• 3.afforestation

• 4.bamboo plantations

Case studies

In past years, there have been some serious and fatal landslides in India:

• Guwahati landslide, Assam: The landslide took place on September 18, 1948 due to heavy rains. Over 500 people died in the landslide and according to the reports, the landslide buried an entire village

• Kedarnath landslide, Uttarakhand: The landslide took place on June 16, 2013 and was the result of Uttarakhand floods. Over 5700 were reported dead and over 4,200 villages had been affected by the floods and post-floods landslide.

• Darjeeling landslide, West Bengal: The landslide happened around October 4, 1968. The landslide was triggered by floods and the 60 km long highway was cut in 91 parts. As per reports, thousands of people died in the landslide.

By:- Kumar Pawar & Aryan Bhondve