Natural Disaster

Natural Disasters result from Natural Hazards like, Earthquakes, volcanoes, tsunami which end up affecting human life due to the inability of humans to cope with the situation. If man is well -prepared for any kind of natural calamity which affects civilization, then maybe the extent of loss to mankind will not be severe.

Let us focus on some of the natural calamities which affect civilization.

Avalanche is caused due to the buildup of snow on a mountain which causes it to slide down forcefully bringing down with it huge rocks and other materials that are present on the mountains.

An earthquake is a sudden eruption of stored energy which releases seismic waves and there is displacement of ground, natural and manmade objects. Seismic waves are waves which travel through the earth.

Lahars is a kind of volcanic eruption which involves the sliding of materials like rock, ash, mud from the sides of the volcano at a rapid pace. These slides are so rapid and fast that they are capable of destroying entire town in seconds killing hundreds and thousands of people immediately.

The best example of a Lahars is the Tangiwai disaster in Columbia.

Landslides are similar to avalanches, only instead of snow, naturally occurring ground materials like rocks, trees, houses etc or whatever can be swept up, slides down causing damage to property and humans. Landslides are caused due to earthquakes, volcanoes or anything which disturbs the ground surface.

A volcano lies inside the earth's surface and it spews hot gases and molten rocks to the surface of the earth. The gases which are emitted are carbon dioxide, carbon monoxide, hydrogen chloride, hydrogen suphide, water vapor. The molten rock is called lava. A fissure in the earths crust forms it.

Deposits of molten material and solid matter from the earths interiors flows into the crust which erupts in the form of a volcano. A huge crater in the shape of a bowl is formed on top of the cone. The study of volcanoes is called volcanology

Active volcanoes are those which have erupted during historic times and dormant volcanoes are those which doesn't show any signs of eruptions but only gas escapes through them.

Volcanic eruptions are small eruptions from a volcano. These eruptions come in many forms, right from daily eruptions to extremely infrequent super volcanic eruptions where the eruptions are equal to 1000 cubic kilometers of materials. Some eruptions are in the form of pyroclastic flows that are clouds of ash and steam that trail down mountainsides at a speed exceeding even airliners.

Tsunami is a huge tidal wave which is caused by underwater earthquakes or volcanic eruptions. Tsunami is derived from the Japanese word. A Tsunami can have speed of 800km/hr and the waves can reach up to 135 ft also above sea level. Tsunamis can have devastating effects which are capable of destroying entire townships located along the seacoast.

A series of waves occur, each higher than the previous one. Generally Tsunamis occur along the ring of fire which is area of volcanoes and seismic activities along the Pacific Ocean. A seismograph is a device by which Tsunami warnings can be alerted.

Tornadoes are the one of the natural disasters pertaining to weather conditions. They are also known as twisters. These winds are extremely violent and which rotate in anti-clockwise direction in the north of the equator and in clock-wise direction in the south of the equator. They look like black funnel extending from the base of the cloud. The Tornado rotates at the rate of 480kph or even faster.

The Tornadoes are not more than 1 km wide but they are capable of destructing vast areas. The air pressure in the center of the tornado is lower than in the surrounding areas. The speed of the wind sends objects flying in all directions and is the cause of destruction of life and property. The Tornado doesn't last in a place for more than few minutes. It skips from place to place because of which some places get devastated while others are untouched.

Tornadoes are caused when cold polar air meets warm tropical air which results in instability caused by the warm rising air. Lightning, rains and hail begin to form and soon the funnel starts descending from the cloud. It is not actually a funnel but when the pressure inside the clouds drop, moisture in the air condenses which comes down in the form of a funnel. This is known as Bernoulli's principle.

In 1925, a killer tornado occurred in US who had a speed of 60 mph and was 220 miles long and 1 mile wide.

Drought occurs when there is no rainfall in a geographic area where there is normally rainfall. There is a severe spell of dry weather conditions. Wells dry up, water-reservoirs dry up, crops are severely affected. Droughts occur when moisture-carrying winds from the oceans or other sources are replaced by dry winds. In such cases, there is a dry spell. If it lasts for a few days then it is known as dry spell. Whereas if the weather conditions prevail it is known as drought.

The effects of drought are many rights from drying of crops, drying of wells, death of wild stock and water habitats, increase in forest fires. Destruction of crops has multiple ill-effects ranging from unemployment of farmers, reduction in income, and increase in prices of crops and also suicides in farmers.

To sum it up, natural disasters are unavoidable, but with planning, foresight and implementation, the impact on human development can be reduced to a considerable extent.