PowerPoint

About

“Natural Disasters”Made By :-

1. Ibrahem Ashraf El-Zahaby2. Mahmoud Mohamed

What are Natural Disasters?

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.

What are Natural Disasters?Earthquake

HurricaneFloodWildfireTornadoTsunami

EarthquakeAn 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.

A hurricane is an intense, rotating oceanic weather system that possesses maximum sustained winds exceeding 119 km/hr (74 mph). It forms and intensifies over tropical oceanic regions. Hurricanes are generally smaller than storms in mid-latitudes, typically about 500 km (311 miles) in diameter. At the ocean’s surface, the air spirals inward in a counterclockwise direction. This cyclonic circulation becomes weaker with height, eventually turning into clockwise (anticyclonic) outflow near the top of the storm.

Hurricane

FloodA 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).

WildfireThe term “wildfire” is used for uncontrolled fire that destroys forests and many other types of vegetation, as well as animal species. In some regions of the world wildfires are caused by lightning however, nowadays many fires are caused by people, either accidentally, as a consequence of carelessness, or arson. These fires often get out of control and spread very easily over vast areas. Depending on the type of vegetation or material being burnt,they are also called: forest fires, bush fires, grass fires, or peat fires.

A tornado is a violently rotating column of air, which extends from a thunderstorm to the ground. The most powerful tornadoes are capable of producing speeds greater than 250MPH. Damage in the path of a tornado can spread more than one mile wide and 50 miles long.

Tornado

A tsunami (soo-NAH-mee) is a series of waves that occur in an ocean or other large body of water and that are caused by some activity that displaces large amounts of water. Tsunami is the Japanese word for "harbor wave."Tsunamis are usually caused by earthquakes that occur on the seafloor or in coastal areas. The energy generated by the earthquake is transmitted through the water. In deep oceans the energy in these seismic sea waves can travel virtually unnoticed because the wave height may be only twelve inches. When this energy reaches the shallow waters of coastlines, bays, or harbors, it forces the water into a giant wave. Some tsunamis may reach heights of 100 feet or more.

Although a relatively rare event, since 1992 tsunamis have claimed over 2,000 lives worldwide. The tsunamis were caused by earthquakes in Japan, Indonesia, and Nicaragua. Damage to cities along coastlines has been in the millions of dollars.