Unit4 Natural disasters 自然灾害课件(31张ppt)

(共31张PPT)
Tsunami
A tsunami is a train of gigantic waves that occur after an earthquake or volcanic eruption. They can be as high as 30 meters or ten feet, travel as fast as a jet plane and go as far inland as 2 kilometers or 1 miles. Most tsunamis happen in the Pacific.
Mudslides
Mudslides are fast moving landslides that occur after heavy rains. They are rivers of mud.They can destroy and kill everything in their path.
Earthquakes
Earthquakes are caused by the movement of the earth’s plates, which lie under the surface of the earth. Earthquakes occur suddenly. 4 out of 5 earthquakes take place in the Pacific Rim.
Avalanche
An avalanche is a like a mudslide except it is made up of snow and ice. They occur in the mountains after fresh snowfalls and can travel at 80 miles an hour or 128 kilometers per hour.
Drought
Drought: A drought occurs when there has not been enough rain so that crops and plants can grow. Farm animals die and people don’t have enough to eat.
Forest Fires
Forest fires are fires that burn in forest areas. Lightning can start them but usually careless people do. There are 100,000 fires in the US every year. They can travel at 14 miles an hour or 23 kilometers an hour and will destroy everything as they move. Drought and hot weather are also responsible for many fires.
Blizzards
Blizzards are severe snowstorms with very high winds, extremely low temperatures, and poor or no visibility. They are especially dangerous for travelers who may get stuck in their cars and could suffer from hypothermia
Typhoons & Cyclones
Typhoons are rotating tropical storms like hurricanes, but they occur in the north-west Pacific Ocean near Hawaii and Asia. Their winds can reach 200 miles per hour/320 kilometers per hour. Cyclones are similar storms in the Indian Ocean. They both have torrential rains and storm surges- causing massive flooding.
Floods
Floods are one of the worst natural disasters and cost the most money. They occur when storms cause rivers to overflow or by high tides. They cause enormous damage and loss of life.
Volcanoes
Volcanoes are explosions that happen from openings in the earth’s surface. Most volcanoes are located in the Pacific Rim. When volcanoes erupt, they spew magma, lava, and ash. There are between 1,300 to 1,500 volcanoes on earth.
Tornadoes
A tornado is a spinning tube of air that touches the ground and a cloud above. They usually travel only a few miles but can destroy everything in their wake.The US has 1200 a year- more than anywhere else in the world.
Hurricanes
Hurricanes are strong tropical storms with high winds and heavy rain that develop in the Atlantic Ocean. Each hurricane has a boy’s or girl’s name. They cause tremendous damage when they hit land. They occur from June until November in the US.
Other Disasters

Heat waves- temperatures over 38C. Or 100F for an extended period of time
Hailstorms- round balls of frozen rain- can destroy crops
Epidemics- fast spreading diseases- some serious others often fatal such as Ebola
Wildfires- out of control fires in inhabited areas- destroy houses and crops
Thunderstorms- lighting can cause fires and kill people
What doesn’t belong
earthquake
fog
tsunami
noise
wind
shaking
Richter Scale
Double click on words.
What doesn’t belong
tsunami
lightning
high waves
tornado
fires
jet speed
earthquakes
Click on the words.
Quiz
Name the natural disaster.
Describe it briefly.
Then
CHECK
CHECK
tsunami
CHECK
earthquake
CHECK
drought
CHECK
avalanche
CHECK
blizzard
CHECK
mudslide
CHECK
volcano
CHECK
forest fire
CHECK
flood
Japan
CHECK
typhoon
CHECK
tornado
Florida
CHECK
hurricane
The End