Natural Hazards and Disasters

Nature can turn dangerous in an instant. An earthquake levels a city, a swollen river drowns a district, a failed monsoon withers a season's crops, a cyclone smashes a coast. India faces almost every kind of natural hazard there is. This is because of its large size and varied geography. Whether such an event becomes a tragedy depends not only on nature but on how well people are prepared. Understanding these hazards and how to manage them is now an essential part of geography.

It helps to separate two terms. A natural hazard is a threatening natural event (an earthquake, a flood, a storm) that could cause harm. A disaster is what happens when that hazard actually strikes a populated area and causes widespread loss of life, injury and destruction of property that the community cannot cope with on its own.

So the same earthquake may be a minor hazard in an empty desert but a terrible disaster in a crowded city. This is why disaster management focuses as much on people and preparation as on the natural event itself.

An earthquake is a sudden shaking or trembling of the ground. It is caused by the movement of the rocky plates that make up the Earth's crust. The point inside the Earth where it starts is the focus, and the point on the surface directly above it is the epicentre. Its strength is measured on the Richter scale.

India is divided into seismic zones according to risk. The Himalayan region and the north-east are the most earthquake-prone. This is because the Indian plate is still pushing against the Asian plate there. A tsunami is a giant sea wave set off by an undersea earthquake. The tsunami of December 2004 struck India's eastern coast and the Andaman and Nicobar Islands with great loss of life. This led India to set up a tsunami warning system.

A flood is the overflowing of a river onto the surrounding land that is normally dry. Floods are the most frequent natural disaster in India. They are caused mainly by heavy rain during the monsoon, when rivers cannot carry the sudden excess of water. The problem is made worse by silt raising the river bed, by deforestation in the catchment, and by poor drainage.

The northern plains, especially the basins of the Ganga and the Brahmaputra, and the state of Assam and West Bengal, suffer the most. Floods destroy crops, homes, roads and livestock, and spread disease. However, the silt they leave behind can also renew the fertility of the soil.

A drought is the opposite hazard: a long spell of dry weather and serious water shortage. It is caused chiefly by the failure or delay of the monsoon rains. So much of Indian farming depends directly on the monsoon. So a drought can ruin the harvest over a vast area.

Drought-prone regions include large parts of Rajasthan, the interior of the Deccan plateau, and other areas of low and unreliable rainfall. A drought brings crop failure, shortage of food and fodder, the death of cattle, and great hardship for farmers, sometimes forcing people to migrate.

Tropical cyclones are violent storms of very low pressure with fierce winds and torrential rain, formed over the warm tropical seas. In India they strike the coasts, especially the east coast along the Bay of Bengal (Odisha, Andhra Pradesh, West Bengal, Tamil Nadu). They bring destructive winds, heavy rain, and a storm surge of seawater that floods low coastal land.

Landslides are the rapid sliding of rock and soil down a steep slope. They are common in the hilly and mountainous regions (the Himalayas and the Western Ghats). They are triggered by heavy rain, earthquakes, and human actions such as cutting roads and clearing forests on slopes.

Because hazards cannot be stopped, the aim is to reduce the damage they cause through disaster management. This works in stages. First comes prediction and early warning, using satellites and weather systems. Then comes preparedness: building cyclone shelters, earthquake-resistant houses, and embankments, and training people. When disaster strikes, the focus shifts to rescue and relief. Afterwards comes rehabilitation to rebuild lives.

In India this effort is led by the National Disaster Management Authority (NDMA), headed by the Prime Minister, with state and district authorities below it. Modern thinking stresses prevention and preparation before a disaster, rather than only responding after it. This makes communities more resilient.