According to Cambridge dictionary hazard is defined as “something that is dangerous and likely to cause damage”. Natural hazard is a naturally occurring physical phenomenon which results in loss of life. These hazards are as old as human history but the dramatic increase and the damage caused by them in the past has become a topic of concern for the human race. There are different types of natural hazards caused since the earth came into existence they are earthquake, droughts, floods, tsunamis, cyclones and landslides.
Earthquake is the most commonly known and most occurring natural hazard. The sudden shaking of the earth’s crust by passage of the seismic waves through the rocks beneath the ground is known as an earthquake. About 50000 earthquakes occur every year and large earthquakes occur at least once in a year. How are earthquakes caused? Or how they occur? The earth’s crust is made up of different plates of varying size. Usually they occur in the belts of tectonic plates. The most important earthquake belt is the Circum-Pacific Belt, which affects many populated coastal regions around the Pacific Ocean. The statistics show that a total of 1,566 earthquakes occurred worldwide in 2017. In India a magnitude of 6.6 Richter scale hit with maximum Mercalli intensity of VIII this occurred near the site of Koyna dam, Maharashtra and claimed at least 177 lives and injured over 2,200 people in 1967.
Drought is lack or deficiency of rain for a long period that causes imbalance of water and eventually water shortages, stream flow reduction, crop damage and depletion of groundwater and soil moisture. It occurs when transpiration and evaporation exceeds the rainfall for a period of time. Drought seriously affects the agricultural land. Drought prone areas in India are in southern and eastern Maharashtra, northern Karnataka, Andhra Pradesh, Odisha, Gujarat, Telangana and Rajasthan. In 2016, 330 millions of people have suffered due to drought.
Flood is a state where high water level along with any water body leads to inundation of land, which is normally submerged. Floods usually occur due to heavy rainfall and when the drainage system in cities is not good enough. Floods cause large number of fatalities in every country, but because of India’s high population density and under developed standards, a huge amount of damage and deaths happen due to excessive rain which then results in overflow of rivers, lakes and dams which causes large amount of damage to people’s lives and property. The clogging of water in cities causes various water borne diseases like typhoid, cholera. In 2005 Mumbai experienced largest flood which witnessed 1094 deaths and a loss of Rs. 550 crore.
Tsunami is a Japanese word meaning harbour waves. Earthquakes caused by seismic sea waves are known as tsunamis. They are series of waves in a water body caused by the movement of large volume of water generally in oceans and seas. Tsunamis and tides both produce waves of water that move inland, but in case of a tsunami, the inland movement of water is much greater, giving the impression of an unbelievably high and forceful tide. Indian Ocean experienced the biggest tsunami in 2004 which affected India, Bangladesh, Malaysia, Myanmar, Thailand, Sri Lanka and the Maldives.
Cyclone is a large system of winds that circulates about the centre of low atmospheric pressure in a counter clockwise direction towards the north of the equator and in a clockwise direction to the south of the equator. Cyclonic winds move generally above the equator and are associated with rains and snowfall. Cyclone Gaja in 2018 hit Tamil Nadu, Andhra Pradesh and some parts of coastal Puducherry with heavy rainfall in Cuddalore and Pamban.
About Author: Gayatri Rasal has total work experience of 1.5 years in corporate world. She loves to train teachers. She is working with STEM Learning from last 1.5 years.