This document summarizes several natural disasters including earthquakes, tornados, cyclones, tsunamis, floods, droughts, and volcanic eruptions. Earthquakes are caused by the sudden release of energy in the earth's crust. Tornados are violently rotating columns of air connecting the ground to storm clouds. Cyclones are large rotating air masses around centers of low pressure that come in tropical, subtropical, and extratropical forms. Tsunamis are large ocean waves caused by displacement of water, like the 1958 Lituya Bay tsunami that was 150 meters tall. Floods result from overflowing water bodies and droughts are long periods with water shortages, like the 1958-1961 Chinese

1. Natural Disasters
By Deikshi

2. Some natural disasters
● Earthquake
● Tornados
● Cyclone
● Tsunami
● Flood
● Drought
● Volcanic eruption

3. 1. Earthquake
● It is the result of sudden release of energy from the earth’s
crust that creates seismic waves.
● Earthquakes are measured using seismographs.

4. 2.Tornados(twisters)
● A tornado is a violently rotating column of air that is
touching both the ground and a cumulonimbus cloud.
● Tornado conditions are caused when different
temperatures and humidity meet to form thunder clouds.
● Twisters can obtain speed up to 100 miles an hour.

5. 3.Cyclone
● A cyclone is a large scale air mass that rotates around
strong centers of low pressure.It has lower pressure
inside and higher pressure outside.
There are three types of cyclones
● Tropical cyclones
● Subtropical cyclones
● Extratropical cyclones

6. 4. Tsunami
● Tsunami means harbour wave and is caused by the
displacement of a larger body of water normally an ocean
or a large lake.
● The biggest tsunami ever happened at Lituya Bay at
Alaska in July 9, 1958. This tsunami was 150 meters tall.

7. 5. Flood
● Floods are caused when water overflows from water
bodies such as rivers, lakes and oceans
● One of the biggest floods in the world is probably the
Yellow river in China in 1887 which killed 900,000 people.

8. 6. Drought
● A drought is a long period of time in which a certain area
receives a shortage of water.
● The three years between 1958 to 1961 was the greatest
chinese famine which was the worst drought on record,
15 to 43 million people died.

9. 7. Volcanic eruption
● The sudden occurrence of a violent discharge of steam
and magma. Volcanic eruptions are measured using
volcanic explosivity index.
● The largest volcano known to humans is Olympus moon
on Mars . It is bigger than the Mount Everest.

10. Sources
● https://www.google.se/search?
q=floods&biw=1517&bih=741&tbm=isch&tbo=u&source=univ&sa=X&ved=0ahUKEwiOk8jZ8KzMAhXqK5oKHeIvBbUQsAQIGg
&dpr=0.9#imgrc=44wCNwuCMsvZ8M%3A
● https://en.wikipedia.org/wiki/Flood
● https://en.wikipedia.org/wiki/Drought
● https://www.google.se/search?q=droughts&biw=1517&bih=741&source=lnms&tbm=isch&sa=X&sqi=2&ved=0ahUKEwibqcSl-
azMAhWHWiwKHQnJDbsQ_AUIBigB&dpr=0.9#imgrc=ALrpcbq0StwYoM%3A
● http://environment.nationalgeographic.com/environment/natural-disasters/avalanche-profile/
● https://en.wikipedia.org/wiki/Cyclone
● http://study.com/academy/lesson/what-are-cyclones-types-causes-effects.html
● http://oceanservice.noaa.gov/facts/tsunami.html
● http://www.publicdomainpictures.net/hledej.php?hleda=white+background
● https://pixabay.com/en/background-abstract-white-989172/

11. Thank you