What is a landslide?

The term “landslide” (or landslip) describes the downward movement of rock, earth or debris due to gravity, especially aggravated during the rainy season.

What causes a landslide?

There are various reasons for occurrence of  landslides. Landslides are usually caused by human activities that disru the area. Landslides also occur during volcanic eruions, earthquakes, and waves.              

However, landslide are categorized into two :-

Ø  There are various reason why a landslide may occur. Natural reasons include earthquakes and heavy rainfall. Human causes include mining operations that use blasting and cNatural causes

Ø  Man made causesMMan made causes

Natural causes

Ø  There are various reason why a landslide may occur. Natural reasons include earthquakes and heavy rainfall. Human causes include mining operations that use blasting and cutting down timber.There are various reason why a landslide may occur. Natural reasons include earthquakes and heavy rainfall. Human causes include mining operations that use blasting and cIntense rainfall will raise the ground water table, decrease the soil’s coherence and increase the weight of associated materials.

Ø  Lowering of the water levels in rivers, reservoirs, etc.

Ø  Erosion caused by continuous run off over a slope.

Ø  Deposition of the loose sediments in a delta area.

Ø  Decomposition of rocks.

Ø  Fluctuation of water levels due to tidal action.

Ø  Ground vibration creating during an earthquake.

Ø  Volcanic activity.

Man Made Causes

Ø  Constructions done without proper engineering inputs.

Ø  Farming practices.

Ø  Removal of vegetation cover and deforestation

Consequences of Landslides.

Direct Losses

Ø  Loss of life: Landslides can result in death and injury of people and animals. The moving mass can bury people and animals under debris.

Ø  Loss of property and assets: The force and speed of debris, mud or earth mass generated due to mass movement may destroy houses, buildings and other properties in its path.

Ø  Loss of infrastructure and lifeline facilities: Earth mass can block or damage infrastructures such as roads, railway, bridges, telecommunication and electrical supply lines, etc.

Ø  Loss of resources: Earth mass can affect water resources in the area by blocking rivers, diverting water ways, blocking irrigation channels, reducing storage capacity of tanks and reservoirs, etc.

Ø  Loss of farmland: Productive lands such as paddy and other crop fields may be covered with debris or blocked from access.

Ø  Loss of places with cultural importance

Indirect losses

Ø  Loss in productivity of agricultural or forest lands: It is due to being buried by debris and lack of access.

Ø  Reduced property values: Due to unwillingness of people to purchase disaster prone land.

Ø  Loss of revenue: Due to loss of productivity, transport problems, etc.

Ø   Increased cost: Due to investments in preventing or mitigating future landslide damage.

Ø  Adverse effect on water quality: Water sources may be contaminated.

Ø  Loss of human productivity: Due to death and injury.

Ø  Reduction in quality of life: Due to death of family members and destruction of personal belongings.

Ø  Impacts on emotional wellbeing

Do's and Don'ts:

Before

Ø  Listen to weather forecast on the radio, TV etc. about heavy rains.

Ø  Observe unusual signs such as appearance of cracks and their rapid expansion over the slope.

Ø  Move away and inform elders when such signs are recognized

Ø  Remain awake during nights of heavy continuous rain and be ready to move to a safer location.

Ø  Listen for abnormal sounds of soil and rock movement or breaking of trees. They may be associated with landslide movements.

Ø  Prepare safe water facilities (covered with a lid).

Ø  Prepare first aid facilities.

During

•  In case you have to evacuate, do so immediately. Do not try to collect belongings. Landslides can occur suddenly
•  When you see falling rocks, seek cover behind trees and other solid objects.
• Landslides, as a result of ground shaking, can create a large volume of mud flow along the slope into the valley. Therefore, do not move in the direction of the valley if you are requested to evacuate, move to elevated areas.
•  If escaping is not possible, seek shelter, curl into a tight ball and protect your head.

After

Ø  Remember: One slide can follow another. Be careful and stay in a safe place.

Ø  Help people who need help.

Ø  Use the telephone only for emergency calls.

Ø  Do not go through the loose and new deposits of debris. You might sink in or cause more sliding.