Something that happens suddenly and causes much suffering or loss to many people. Disaster is an undesirable occurrence resulting from forces that are largely outside human control, strikes quickly with no warning, which causes or serious disruption of life and property including death and injury to a large number of people. Disasters are also caused by some human activities like Bhopal Gas tragedy, Chernobyl nuclear disaster, wars, release of CFCs (Chlorofluorocarbons) and increase of green house gases, environmental pollutions. Landslides and floods are caused indirectly by humans due to deforestation, unscientific land use etc.
Natural disasters in India
India had faced several natural disasters includeing earthquakes, tsunami and landslides. Which caused heavey distruction.
- Earthquake: It is most unpredictable and highly destructive of all the natural disasters. It is caused due to tectonic activities in the earth crust. Indian plate is moving towards north and Northeastern direction and this movement is obstructed by Eurasian plate from the north. As result, both the plates are said to be locked with each other resulting directly in accumulation of energy at different points of time. Excessive accumulation of energy results in building up of stress, which leads to the breaking up of the lock and sudden release of energy causes earthquakes. Some vulnerable states are Jammu and Kashmir, Himachal Pradesh, Uttaranchal, Sikkim, Darjiling, sub division of West Bengal and all seven states of Northeast. More than 1200 earthquake that have occurred in India in different past years. India has been divided into five earthquake zones:
- Very high damage risk zone
- High damage risk zone
- Moderate damage risk zone
- Low Damage risk zone
- Very low damage risk zone
Both very high and high damage risk zone have these areas: North-east states, areas to the north of Darbhanga and araria along the indo-Nepal border in Bihar, Uttaranchal, Western Himachal Pradesh (around Dharamshala) and Kashmir Valley in the Himalayan region and the Kuchchh (Gujarat). The remaining parts of Jammu and Kashmir, Himachal Pradesh, Northern parts of Punjab, Eastern parts of Haryana Delhi, Western Uttar Pradesh, and Northern Bihar. Remaining part of country falls under moderate, low and very low damage risk zone. Intensity of Earthquake is measured by Richter scale.
- Tsunami: Earthquakes and volcanic activity cause the sea floor to move abruptly resulting in sudden displacement of ocean water in form of high vertical waves are called tsunami or seismic sea waves. Tsunamis are frequently observed along the Pacific ring of fire, particularly along the cost of Alaska, Japan, Philippines, and other islands of Southeast Asia, Indonesia , Malausia, Myanmar, Sri Lanka, and India etc.
- Tropical Cyclone: Tropical cyclones are intense low pressure areas lying between 30° N and 30° S latitudes, in the atmosphere around which high velocity winds blow. Horizontally, it extends up to 500—1,000 km and 12-14 km vertically. A tropical cyclone or hurricane is like a heat engine that is energized by the release of latent heat on the condensation of moisture that the wind collect after moving over the oceans and seas.
- Floods: It occurs slowly. Floods occur due to heavy increasing of runoff water of rivers and streams. Floods can also be caused due to a storm surge (in the coastal areas), high intensity rainfall for a considerably longer time period, melting of ice and snow. Assam, West Bengal and Bihar are high floods prone states in India.
- Drought: Word ‘Drought’ is used to a period when there is a shortage of water availability due to excessive rate of evaporation and over utilization of water from the storage, including the ground water.
- Meteorology Drought
- Agriculture Drought
- Hydrological Drought
- Ecological Drought
Drought prone areas in India: According to some estimates, nearly 19 per cent of the total geographical area of the country and 12 per cent of its total population 5 suffer due to drought every year. About 30 per cent of the country’s total area is identified as drought prone affecting around 50 million people.