Landslides have caused massive damage of life and property during extremely heavy rain across India. The Kedarnath landslide in Uttarakhand in June 2013, caused by flash floods that resulted in over 5,000 deaths, was identified as the most tragic such disaster. Recently a landslide hit Kinnaur district in Himachal Pradesh, which happened for the second time in 15 days, killing at least 14 people and burying many others. The tragedy was exacerbated by heavy rain, hailstones, and debris on vehicles, including a state-of-the-art transport bus on National Highway 5.
15% of India's landmass is prone to landslides, however, its vulnerability will increase in the future due to climate change and human pressure. This improved size can be considered by adopting a multidisciplinary approach that integrates all aspects of disaster risk management namely mitigation, preparedness, response, and rehabilitation.
What is landslide?
Landslides are the rapid movement of rock, soil, and vegetation under a slope under the influence of gravity. It can be caused by natural factors, e.g. Heavy rain, earthquakes, or can be caused by extreme human disturbance of the slope - stability. Landslides are rarely at the same level as earthquakes or volcanic events. The magnitude and magnitude of landslides, however, depends on the geological structure, the slope angle of the slope, the nature of the mountain rocks, and the interaction of people with the slope. As per Geological Survey of India, the window of economic loss due to landslides may reach between 1-2% of the gross national product in many developing countries.
Causes of Landslides
The main causes of landslides are
- Rain and snow
- Excessive or continuous rainfall can lead to massive landslides in the high slopes where National Highways and roads are built.
- The Nashri region between BatoteRamban-Ramsu, and Banihal (Jammu and Kashmir) is prone to landslides. Landslides in this area are especially difficult during the rainy season and winter when car traffic is disrupted for a few days.
- Earthquakes and volcanic eruptions
- Earthquakes are a major cause of landslides in mountainous areas. In India, Landslides are more common in the rolling hills of the Tertiary Period, such as the Himalayas.
- In the Kashmir region, the 1905 earthquake caused a landslide in the small Himalayas and the Greater Himalayas in which several thousand people lost their lives.
- Volcanoes also cause landslides in mountainous areas.
- Mining, Mining and Cutting Road
- The continued extraction of coal, minerals, and minerals from the mines and quarries and the construction of roads by cutting slopes on the rolling hills create the ideal conditions for the availability of soil extraction.
- Such landslides can be seen throughout the Himalayas and in the Eastern and Western Ghats.
- Loading about housing
- The unplanned growth of cities and towns in hilly areas without exploring soil and rock is also an important cause of landslides.
- The eastern slope of Nanital (Uttarakhand) is sinking due to the heavy load of hotels and residential buildings.
- Deforestation and other human activities also cause landslides. Most landslides are minor involving some blocks up to a few meters across. But some are big enough to cause disaster. They can bury roads, buildings, and other structures.
- The negative effects of erosion can be reduced by observing deforestation on mountain slopes, by following the building codes of these areas, and by avoiding the construction of buildings on steep slopes.
Types of Landslides
- Falls: It happens due to the abrupt movements of the mass of geologic materials, such as rocks and boulders, that become detached from steep slopes or cliffs.
- Topples: It happens due to the forward rotation of a unit or units about some pivotal point, under the actions of gravity and forces exerted by adjacent units or by fluids in cracks.
- Slides: In this type, rocks, debris, or soil slide through slope forming material.
- Spread: It usually occurs on very gentle slopes or flat terrain.
India among the countries most affected by landslides due to human activities:
- Earthquakes caused by human activities are increasing worldwide and India is among the worst-affected countries, accounting for at least 28% of such incidents over the past 12 years, according to a published study.
- Investigators have collected data on more than 4,800 deadly earthquakes that occurred from 2004 to 2016, leaving behind those caused by earthquakes.
- More than 56,000 people have been killed by landslides worldwide during this time, most of them affected by one slope, according to a study based on the Global Fatal Landslide Database (GFLD).
- At least 700 of these deadly landslides were caused by construction work, illegal mining, and uncontrolled rolling of hills.
- While the trend is global, Asia has been found to be the most affected continent where 75% of landslides occurred, with the highest number reported near the Himalayan Arc.
- All 10 countries in the world of deadly humanitarian catastrophes are located in Asia. India accounts for 20% of these cases.
- The study states that fatal soil erosion is on the rise in India, where landslides caused by construction occur during this period, followed by China (9%), Pakistan (6%), the Philippines (5%), Nepal (5%) and Malaysia (5%).).
- We knew that people were putting increasing pressure on the local community, but it was surprising to find the obvious trend in the database that deadly landslides caused by construction, illegal mountain cutting and illegal mines were increasing worldwide during this time.
Vulnerability profile of India
In India, the hazard affects at least 15% of the world's land area (approximately 0.49 million square km.) It is most common in geodynamical operating areas in the Himalayan and Arakan-Yoma areas in the north-eastern part of the country and as in the more stable areas of Meghalaya Plateau, Western Ghats and Nilgiri Hills. The Nilgiri Mountains, located at the confluence of the Eastern and Western Ghats, bear countless scars from landslides.
Consequences of landslides
- Loss of Life: The most devastating effect of landslides is the loss of precious human and animal life. In the latest Kinnaur Landslide, 14 deaths have already been reported.
- Restrictions on Travel: Mud, rocks, and sloping debris create a barrier to critical transport routes such as highways, railways, etc. This prevents the movement of goods and people.
- Infrastructure Damage: Several houses, buildings, roads, and other infrastructure are damaged whenever an earthquake occurs.
- Economic Loss: The amount of money spent restores lost infrastructure, mass rehabilitation, and the provision of relief services to affected people.
- Risk of Water Availability: When soil erosion occurs on slopes of a river valley, the size of the sliding can reach the bottom of the valley and cause partial or complete closure of the river channel. This pile of debris leading to the river closure is often called the Landslide dam. It can affect the availability of water to nearby people.
Measures taken for land management in India
- National Disaster Risk Management Strategy (2019): Addresses all aspects of disaster risk reduction and management, including risk mapping, monitoring and early warning systems, awareness programs, skills development, training, regulations and policies, stabilization and landslide reduction, etc.
- Hazard zones have to be identified and specific slides to be stabilized and managed in addition to monitoring and early warning systems to be placed at selected sites.
- Hazard mapping should be done to locate areas commonly prone to landslides. It is always advisable to adopt area-specific measures to deal with landslides.
- Restriction on the construction and other developmental activities such as roads and dams, limiting agriculture to valleys and areas with a moderate slope, and control on the development of large settlements in high vulnerability zones, should be enforced.
- NDMA Guidelines for Landslides –
- Landslide Hazard, vulnerability and Risk Assessment
- Multi – Hazard Conceptualisation
- Landslide Remediation practice
- Research and Development, monitoring, and early warning
- Knowledge network and management
- Capacity building and Training
- Public awareness and Education
- Emergency preparedness and response
- Regulation and Enforcement
- Firstly, provinces such as Himachal Pradesh and Uttarakhand in high-risk areas should be especially vigilant in pursuing disruptive projects. There should be a proper implementation of the environmental impact assessment procedures prior to the start of mining or dam construction.
- Second, there should be the adoption of small-scale zoning processes for mountains and other high-risk regions.
- Third, more funding should be made to planning and demolition agencies and reducing structures to improve disaster management.
- Fourthly, there should be the involvement of trained staff in the area to strengthen the reduction of public awareness programs and programs.
- Fifth, mitigation strategies such as limiting agriculture in the valleys and areas with moderate slopes, promoting large-scale deforestation programs, and building masses to reduce water flow, etc.
- Increased human encroachment on the environment has led to an increase in the number of natural disasters.
- However, the National Disaster Response Force under The Disaster Management Act, 2005 has carried out many rescue operations by providing assistance and assistance to the affected country, including deployment, at the request of Government, Armed Forces, Central Military, and similar communications, air and other supplies. They have also worked to increase public awareness to reduce the impact of these natural disasters by organizing preparedness campaigns.