Nature has provided life on the earth . Nature is not only a creator of the different living and non – living things but it is also a destroyer of these things . Natural calamities are these destroyer . These are also known as the disasters . The disasters such as floods , droughts , earthquakes , cyclones , tsunamis , landslides and the forest fires cause great loss of life and property.
Let us understand about these disasters :
Our Earth’s crust is based on tectonic plates . These plates are in constant motion as they are on the Earth ‘s mantle which is made of molten rocks. Whenever these plates collide with each other , major or minor earthquakes occur . Earthquakes are a very regular activity. Most of the time , the earthquakes are so minor that they are not even felt by us . However , when the collision are of greater intensity , the earthquakes are felt very strongly.
The point where the quake starts is called the focus and the main point on the surface where the force is transferred is called the epicenter. Epicenter is the place of most damage in an earthquake. High magnitude or high intensity quakes can trun huge building to rubbles in few seconds. The earthquake in Japan in 2011 has been a horrific example of this.
- Proper techniques of construction should be followed while constricting buildings. Structural safety of the building and earthquak resistance measures should always be adopted.
- During an earthquake , one should not stand near the outer walls or windows.
- If it is not possible to get out of the building . One must take cover under heavy furniture.
- Regular drills to aware people of the Dos and Don’ts must be carried out in schools and offices to make people aware of safety measures.
Tsunami is a Japanese term meaning ‘harbour waves’ . There can be many reasons for tsunamis like underwater earthquakes , volcanic eruption or high intensity underwater explosions . Tsunami comes when the seabed is distrubed . It displaces large amounts of water .
Tsunami only come in the coastal areas. But , they can be very disastrous as the waves rise like tidal waves . These huge waves carry massive quantities of water and they can travel much further inside the coast posting a threat to life and property . The fearful tsunami in the Indain Ocean in 2005 affected 14 countries including our country and some of its neighbours and claimed more than 2,30,000 lives.
- The people living in coastal areas must listen to the tsunami warnings and never ignore them.
- They should not go near the coasts during such times.
- Whenever there is a warning sign, one should try to evacuate low lying coastal areas and reach the higher areas.
When the magma under the earth’s crust spills over on it’s surface , it is called a volcanic eruption. The molten magma under the pressure of heat keeps thrusting the crust or lithosphere. When it gets a weak surface , it makes an opening there.
The magma that comes out of the earth is called lava. Huge amount of ashb, molten rocks in the form of lava and gases erupt form a volcano through an opening called a vent. When a volcanic eruption cools off, it takes the shape of a mountain ; the bowl shape hollow formed at the top is called a crater .
- The known sites of recent volcanic activities should be avoided for habitation.
- The signs of eruptions are visible much before an actual volcanic eruption . People sholud immediately evacuate an area surrounding the volcano in such case.
- There should be proper evacuation plan for people in case of volcanic eruption.
- People should be made aware of the risks and explained the measures to be followed during evacuation procedure.
Floods generally occur when there is a heavy rainfall. During heavy rains , rivers overflow and flood the surrounding areas. Excess rain and deforestation result in soil erosin in the mountains followed by floods in the plains. Floods cause excessive loss of life and property.
Houses are washed away , cattle die in large numbers and crops are destroyed. Death of many people because of drowning , snake bites , fever and infections after a flood. Destruction of crops , occurrence of famine-like condition . Loss of jobs , migration of people to cities in search of jobs . The farmers are the major victims.
- Flood-prone areas should be built taking into consideration the inflow of water during floods.
- The drainage system of such areas must be made more adaptive to floods , so that water can be drained easily.
- Evacuation measures should be made adequate for such areas in case of emergencies.
- Adequate quantities of food , water , medicine and other necessary items should always be stocked in such areas for emergencies.
- Drinking water must be boiled use.
- Afforestation is a mandatory precautions for the flood-prone areas.
The excess rainfall causes floods while it’s scarcity causes droughts. In India , agriculture is the main occupation of three-fourths of the population. Farmers depend on the monsoonal rain from June to September. Monsoon provides water for growing crops. The monsoons in India are very erratic , sometimes they are early and other times , they are late . This results in the scarcity of food grains , starvation and death of a large number of cattle and people.
- Proper reservoirs and water tanks need to be built and maintained to conserve water.
- Rainwater harvesting measures need to be implemented strictly in every household and building of the drought-prone areas.
- Recycling of waste water is a good option in such areas.
- Water storage structures like dams should be built in such areas to suppy water in times of drought.
Cyclones occur due to the low-pressure systems towards which winds travel at great speed . The coastal belts in India are prone to cyclones . These areas experience a great difference between temperature and pressure condition on land and sea.
Near the coastal areas , water level rises suddenly and lashes onto the land destroying buildo and crops.
Strong winds with speed of over 100 km per hour or more uproot trees , telephone and electric poles and also destroy whatever comes in their way.
Cyclones are more frequent in the coastal Gujarat , Odisha , West Bengal and Andhra Pradesh . In these areas , they have caused severe damage to life and property.
- Early warning system should be installed in the cyclone-prone areas to warn people.
- People should move to safer places in times of cyclones.
- Tree plantation in such areas should be promoted as it helps in countering cyclones.