What is Landslide?
Have you seen or heard of a mass movement land? Have you noticed the news that some roads in the mountains were closed due to landslides? Well, in this article, we will only discuss this mass movement of landmass. We will learn about the meaning of landslides, the impact of landslides, the causes of landslides, efforts to prevent or overcome them and so on. This article will help you understand a very important geographical phenomenon, namely landslides and related concepts.
Landslides are a natural phenomenon, but it involves many human activities which lead to the mass movement of landmass. In recent times we find the causes of landslides increasing day by day and the primary cause is deforestation. To survive, one needs to keep a check on these human activities.
More on the Topic
The movement of the rocks or debris etc., on a slope downwards, is called a landslide. It is a type of "mass wasting ", which refers to the movement of any mass, soil, or rocks under the influence of gravity. It is one of the natural hazards and can be a disaster if the damages occur in large amounts.
According to the Oxford learners dictionary, "landslides is a mass of earth, rock, etc. that falls down the slope of a mountain or a cliff ".
Types of Landslides
They can occur because of various reasons. We can classify them into four categories which are mentioned below:
Falls Landslides
It means falling of some material or debris or rocks etc., from a slope or a cliff which leads to a collection of this debris at the base of the slope.
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Topple Landslides
These can occur because of some fractures between the rocks and the tilt of the rocks because of gravity without collapsing. Here, we see the forward rotational movement of the material.
Slides
It is a kind of landslide when a piece of the rock slides downwards and gets separated from it.
Spread
It happens on flat terrain and gentle slopes and can occur because of softer material.
Causes of Landslide
Landslides are caused by various factors, which are mentioned below:
It can be caused because of heavy rain.
Deforestation is also one of the main reasons for landslides because trees, plants, etc., keep the soil particles compact and due to deforestation, the mountain slopes lose their protective layers because of which the water of the rain flows with unimpeded speed on these slopes.
It can be caused by earthquakes as well.
For example, in the Himalayas, the tremor occurred because earthquakes unstabilized the mountains, which led to landslides.
Volcanic eruptions in specific regions can also cause landslides.
Landslides often occur in mountain regions while making roads and construction; a large number of rocks has to be removed, which can cause landslides over there.
In the regions of North East India, landslides occur because of shifting agriculture.
Due to the increasing population, a large number of houses are being created, which leads to the creation of a large amount of debris which can cause landslides.
Effects of Landslide
Let us look at the effects of landslides in points:
Landslides can disturb the social and economic environment with the number of other damages which are mentioned below:
Short Term Impacts
The natural beauty of the area is damaged.
Loss of life and property
Roadblocks
Destruction of railway lines
Channel blocking because of the falling of rocks.
It leads to the diversion of river water, which can cause floods as well.
Long Term Impacts
Landscape changes can be permanent.
The loss of fertile land or cultivation land.
Erosion and soil loss can lead to environmental problems.
Population shifting and migration.
Effects on the sources of water.
Some roads can be damaged or closed permanently.
Prevention and Mitigation
The following measures can be taken in this regard:
The country should identify the vulnerable areas and actions should be taken in this regard on a priority basis.
Early warning systems and monitoring systems should be there.
Hazard mapping can be done to identify the areas which are more prone to landslides.
Restriction on the construction in the risky areas should be imposed.
Afforestation programs should take place.
Restricting development in landslide areas and protecting the existing ones.
The country should specify codes or standards etc. For the construction of the buildings and other purposes in such areas of risk.
Insurance facilities should be taken by the people to deal with the loss.
Terrace farming should be adopted in hilly areas.
Response teams should be quick to deal with landslides if they occur.
Landslides in India
It is one of the natural hazards in India, which affects 15% of the geographical area of our country. Due to several factors, India is divided into the following vulnerability zones, which are shown in the table below:
Did You Know?
The North India Flood Mudslides that occurred in Kedarnath, India in June 2013 was one of the deadliest landslides in the world. Around 5700 people died in this disaster. It was one of the worst disasters ever to occur in India.
Endnote:
Thus, in this article, we have covered a very important topic namely landslides. We have covered its related concepts like causes, effects, prevention, and mitigation, etc. Hence, it is very important to learn these kinds of topics. These notes will help you in Geography, Environment, and Disaster Management. So, we have read about the landslide information, effects of landslides, etc. Let's look at some FAQs in the following.
FAQs on Landslide
1. What is a landslide in the context of geography?
In geography, a landslide is defined as the movement of a mass of rock, debris, or earth down a slope. It is a type of mass wasting, which refers to any down-slope movement of soil and rock under the direct influence of gravity. Landslides can range from very slow movements (creep) to sudden, catastrophic events.
2. What are the primary causes and significant effects of landslides?
The causes and effects of landslides are varied and can have major impacts on both the environment and human life.
Primary Causes:
Natural Causes: Heavy rainfall saturating the soil, earthquakes or volcanic eruptions shaking the ground, and natural erosion of slopes by rivers or glaciers.
Human-made (Anthropogenic) Causes: Deforestation that removes tree roots binding the soil, improper excavation of slopes for roads and buildings, and vibrations from mining or heavy traffic.
Significant Effects:
Loss of Life and Property: Buildings, infrastructure, and agricultural land can be buried or destroyed.
Infrastructure Damage: Roads, railway lines, and communication networks are often blocked or damaged, isolating communities.
Environmental Impact: Can block rivers, leading to flooding, and destroy natural habitats.
3. What are the different types of landslides?
Landslides are classified based on the type of material and the nature of the movement. The main types include:
Falls: Abrupt movements of rock or earth that detach from steep slopes or cliffs.
Topples: The forward rotation of a mass of rock or earth out of a slope about a pivot point below it.
Slides: The downward movement of a block of material along a distinct, sliding surface. These can be rotational (slumps) or translational.
Flows: The movement of water-saturated material that behaves like a fluid. Debris flows and mudflows are common examples.
Creep: The very slow, steady, downward movement of soil or rock, often unnoticeable except through its long-term effects on structures.
4. How can the risk of landslides be mitigated or reduced?
Landslide mitigation involves several strategies aimed at preventing or reducing their impact. Key methods include:
Afforestation: Planting trees and vegetation on slopes helps bind the soil with roots, increasing its stability.
Building Retaining Walls: Constructing walls at the base of a slope can help hold back earth and rock.
Improving Drainage: Creating proper drainage systems prevents water from saturating the slope, which is a major trigger for landslides.
Terrace Farming: In hilly regions, cutting slopes into steps (terraces) reduces the gradient and slows down the flow of water.
Land-Use Zoning: Avoiding construction in highly vulnerable, landslide-prone areas is the most effective preventive measure.
5. How do human activities like deforestation and construction specifically contribute to making slopes unstable?
Human activities directly destabilise slopes in several ways. Deforestation removes the network of tree roots that act as natural binders for soil, making the soil loose and easily washed away by rain. Construction activities, such as cutting into a hillside to build roads or houses, over-steepen the slope and remove the natural support at its base. The added weight of buildings can also put excess pressure on the slope, increasing the likelihood of failure under triggers like heavy rain or minor tremors.
6. Why is it so difficult to predict the exact timing of a landslide, even if an area is known to be at risk?
While scientists can identify landslide-prone zones by studying geology, slope angle, and past events, predicting the exact time and date of a landslide is extremely difficult. This is because landslides are triggered by a combination of factors that are hard to forecast precisely. The final trigger could be a specific, intense burst of rainfall, a minor earthquake, or gradual weakening over time that reaches a sudden breaking point. We can map the hazard (where it might happen), but predicting the exact triggering event remains a significant scientific challenge.
7. Which regions in India are most prone to landslides and why?
In India, the two most landslide-prone regions are the Himalayas and the Western Ghats. The Himalayas are vulnerable because they are geologically young, tectonically active mountains with steep, unstable slopes. The Western Ghats, while more stable, experience very high seasonal rainfall during the monsoon, which saturates the steep slopes and triggers frequent debris flows and slides. Unplanned development in both these regions further increases the risk.
8. What is the key difference between a landslide and an avalanche?
The key difference between a landslide and an avalanche lies in the material that moves. A landslide involves the downward movement of soil, rock, mud, or debris. In contrast, an avalanche is specifically the rapid flow of a large mass of snow and ice down a mountainside. While both are types of mass movements driven by gravity, their composition is entirely different.
