Natural Disasters and Hazards in India - Class VII

The Ganges river system, particularly its northern tributaries originating in the Himalayas, is the primary cause of frequent flooding in the plains of Uttar Pradesh.

Forests naturally absorb water from rainfall and slowly release the water into the rivers. After deforestation, rainfall flows too quickly to the rivers, stripping the topsoil and causing erosion and flooding to occur. When these floods break the river's banks, further problems arise as the path of the river changes and further soil erosion occurs along the river's new path. Deforestation also makes an area more arid, contributing to droughts.

A flood is an overflow of water that submerges land, which is classified as a natural disaster caused by meteorological or hydrological events.

Flash floods are defined by the speed of flooding, not the source or location of flooding. While flash floods are often caused by heavy rainfall, they can also result from other events, such as drain blockages and cloud bursts

A flood is an overflow of water that submerges land which is usually dry. The European Union (EU) Floods Directive defines a flood as a covering by water of land not normally covered by water. In the sense of "flowing water", the word may also be applied to the inflow of the tide.

Floods are complex events that can vary significantly in their physical characteristics, including the volume of water (size), the velocity of the current, and the duration of the inundation.

The Himalayan mountain region is located along a major tectonic plate boundary (the collision zone between the Indian and Eurasian plates), making it one of the most seismically active and earthquake-prone areas in the world.

According to geographical and disaster management statistics in regions like India, approximately 68 to 70 percent of the cultivable land is vulnerable to drought conditions due to erratic rainfall and dependence on monsoons.

Rajasthan.

Droughts is expected to result in increased displacement is the area of so-called slow-onset disaster in which climate change has specific long-term environmental effects over time such as desertification and other changes in weather patterns, which means that people’s livelihoods are no longer sustainable and they are forced to migrate to other places.

Drought is a prolonged period of deficient rainfall, which directly leads to crop failure and reduced agricultural productivity.

Mangrove forests have complex root systems that stabilize shoreline sediments, dissipate wave energy, and trap coastal soils, thereby effectively preventing coastal erosion.

Rajasthan, Gujarat, and parts of U.P. are known for being drought-prone. Punjab is a region with extensive irrigation and is generally not considered drought-prone.

Landslides represent a wide range of ground movements, including rock falls, slope failures, and debris flows, all categorized under mass wasting.

An avalanche is essentially a landslide of snow, where a large mass of snow and ice moves rapidly down a mountain slope.

Landslides are triggered by factors that reduce the stability of a slope, such as heavy rainfall, tremors (earthquakes), or the inherent instability of the rock/soil structure.

On 30 July 2014, a landslide occurred in the village of Malin in the Ambegaon taluka of the Pune district in Maharashtra, India. The landslide, which hit early in the morning while residents were asleep, was believed to have been caused by a burst of heavy rainfall, and killed at least 151 people. The landslide was first noticed by a bus driver who drove by the area and saw that the village had been overrun with mud and earth. In addition to those dead, more than 160 people, and possibly up to 200, were believed to have been buried in the landslide in 44 separate houses. Rains continued after the landslide making rescue efforts difficult.

Keeping in view the terms of reference of the Core Group, the Government of India has declared the Geological Survey of India as the ‘Nodal Agency’ on 29 January 2004.

Geological Survey of India as a Nodal Agency is responsible for:

1. Coordinating and undertaking geological studies for landslide hazard mitigation
2. Carrying out landslide hazard zonation
3. Monitoring landslides and avalanches
4. Studying the factors responsible for sliding and suggesting precautionary as well as preventive measure
5. National Core Group has finalized the action plan for landslide studies with inputs of GSI and other organization.

A sturzstrom is a long-runout landslide that involves a large volume of rock and debris, often moving at high speeds.

Coastal erosion is confined to southwest monsoon season when the waves are rough. Seawalls and groynes are the major management strategies adopted for coastal protection along Kerala coast. As per Shoreline Change Assessment data, about 63 percent of the coastline of Kerala is eroding.