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Natural calamities
Presentation by Nayana .P
and Jitendra KumarCollege of Fisheries, KVAFSU, Mangalore,
A natural disaster is the effect of a natural hazard- (e.g. flood, tornado, hurricane, volcanic eruption, earthquake, or landslide) that affects the environment, and leads to financial, environmental and/or human losses.
The World is always changing.
Natural disasters are changes which are so great they may cause damage to the shape of the land or to the lives of people and other living things.
Great changes happen deep inside the Earth and on its surface. The changes on the outer part of the Earth happen because of different kinds of weather.
Volcanic eruption Earthquake Cyclone or Hurricane Monsoons Avalanche Flood Drought Forest fire or
Bushfire Tsunami Electrical storms
A volcanic eruption is the spurting out of gases and hot lava from an opening in the Earth’s crust.
Pressure from deep inside the Earth forces
ash, gas and molten rock to the surface.
A volcano is a mountain or hill formed by the accumulation of magma or molten rock
Volcanoes are hazardous to wildlife and humans alike
Volcanic Gasesan incredible surge of sulfur dioxide gas into the stratosphere where it combined with water to form sulfuric acid. The new aerosol deteriorated the Earth's ozone layer by altering the chlorine and nitrogen compounds.But even when a volcano isn't erupting, it emits gases from fumaroles, cracks or openings from the ground. Most of these gases is water vapor which combines with carbon dioxide, sulfur dioxide, hydrogen sulfide, hydrogen, and fluorine to produce harmful gases such as acid rain. The extra carbon dioxide in the air will result in animal and human deaths
Landslides
Landslides are also very common with volcanoes. The terrible shaking of an eruption causes the loose debris on the side of the mountain to rapidly fall down its steep flank. However, debris avalanches may also be caused by earthquakes or heavy rainfall. Mount St. Helens eruption caused the largest volcano landslide in recorded history, while Mount Rainier have had at least five large avalanches within the past 6,00 years. Such massive landslides result in a complete burial of surrounding cities and the obliteration of wildlife and such.
Lahars
However, of all the effects of volcanoes, mudflows or lahars are the deadliest. Debris flows of mud, rock, and water travel down the flank and into valleys and streams at velocities of 20 mph to 40 mph. Some of the most extreme cases have lahars with a consistency of wet concrete flowing up to 50 miles.
An earthquake is a violent shaking of the ground. Sometimes it is so strong that the ground splits apart.
When parts of the earth, called plates, move against each other giant shock waves move upwards towards the surface causing the earthquake.
Earthquakes release an incredible amount of energy and are able to destroy bridges, buildings, and even entire cities in just a few minutes.
Below are some pictures of some of the most destructive earthquakes in recent history.
A Cyclone is a fierce storm with storm winds that spin around it in a giant circle. During a cyclone trees can be uprooted, buildings can be destroyed and cars can be overturned.
Hurricanes can combine the effects of other natural disasters, proving especially destructive
The monsoon is a wind current in Southern Asia, blowing northeast during the summer and southwest during the winter.
During the summer, the monsoon brings heavy rains to southern Asia and Africa, while in the winter it causes the drier seasons.
The effects of the winter monsoons are very different from the summer monsoons.
During winter monsoons, the wind blows from the land to ocean, while in the summer it is the opposite.
This can cause major climate changes throughout the entire world, depending on the location.
An Avalanche is a movement of snow, ice and rock down a mountainside. Avalanches happen very suddenly and can move as fast as a racing car up to 124mph.
Avalanches can be caused by –
snow melting quickly
snow freezing, melting then freezing again
someone skiing
a loud noise or an earth [email protected]
A flood is caused by an overflow of water which covers the land that is usually dry.
Floods are caused by heavy rain or by snow melting and the rivers burst their banks and overflow.
Costal floods are caused by high tides, a rise in sea level, storm waves or tsunami (earthquakes under the sea).
Floods make an enormous impact on the environment and society.
Floods destroy drainage systems in cities, causing raw sewage to spill out into bodies of water.
This can lead to catastrophic effects on the environment
Floods cause significant amounts of erosion to coasts, leading to more frequent flooding if not repaired.
Floods make an enormous impact on the environment and society. Floods destroy drainage systems in cities, causing raw sewage to spill out into bodies of water. Also, in cases of severe floods, buildings can be significantly damaged and even destroyed. This can lead to catastrophic effects on the environment as many toxic materials such as paint, pesticide and gasoline can be released into the rivers, lakes, bays, and ocean, killing maritime life. Floods may also cause millions of dollars worth of damage to a city, both evicting people from their homes and ruining businesses. Floods cause significant amounts of erosion to coasts, leading to more frequent flooding if not repaired.
A drought is the lack of rain for a long time.
In 1968 a drought began in Africa. Children born during this year were five years old before rain fell again.
Effects
•Drought, of itself, is a devastating event, leading to crop loss and possible topsoil loss
•Drought can weaken an ecosystem by stressing plant and animal resources.
•Flora and fauna not able to find adequate resources are more vulnerable to predation and disease
•Dry conditions can increase not just the number but the severity of fires
Drought, of itself, is a devastating event, leading to crop loss and possible topsoil loss. It also carries another equally serious impact. Dry, compacted soils provide little opportunity for rainwater to penetrate during storms. Drought-affected areas then become vulnerable to floods. Stream banks are easily eroded without the soil-anchoring vegetation lost during a drought. A buildup of forest litter also increases the risk of wildfires.
The effects of drought can be felt in every aspect of society, the economy and the environment. While the immediate effects are devastating, long term effects can persist, compounding damage and loss.
Fires can burn out of control in areas of forest or bush land. Fires are caused by lightning, sparks of electricity or careless people. Wind may blow a bushfire to areas where people live.
Fire effects are the physical, chemical, and biological impacts of fire on ecosystem resources and the environment. abiotic effects of fire include its role in changing air quality, water quality, soil properties, and nutrient cycling. Biotic effects include altering vegetation and related impacts on wildlife.
A tsunami is a series of tremendous waves generated by a massive underwater disturbance.
Tsunamis can move at speeds as high as 500 miles per hour.
Tsunamis are capable of causing a substantial amount of damage.
One tsunami can destroy an entire coastal village and remove all the sand from a beach and sand that took hundreds of years to accumulate.
Electrical storms are composed of lightning and thunder, typically accompanied by heavy precipitation.
Each storm forms in large cumulonimbus clouds (thunderheads) stretching one to five miles in diameter with a height of 25,000 feet.
Electrical storms
Electrical storms are an amazing phenomenon.
it is not considered a very dangerous natural disaster.
It is a very isolated event as each lightning strike only affects a minimal area and rarely kills or injures humans and animals.
Lightning does contain a significant amount of power, reaching temperatures hotter than the surface of the sun, and creating shockwaves that we hear as thunder
A tree split in half by lightning
A forest fire caused by an electrical storm
Lightning over a city at night Lightning striking a tall [email protected]
Natural Disaster Effects | eHow.com http://www.ehow.com/about_5552385_natural-disaster-effects.html#ixzz1cjJfQDzt
Read more: How do Droughts Effect the Ecosystem? | eHow.com http://www.ehow.com/how-does_5448138_do-droughts-effect-ecosystem.html#ixzz1cjl7obAV
library.thinkquest.org/03oct/00758/en/disaster/.../effects.html
human-impact-owww.earthquake.tvn-the-natural-environment
