1. Common Natural Disasters Alexis (Zhuo Tong) Zhang

2. What is natural disaster? A natural disaster is a major adverse event resulting from natural processes of the Earth; examples include floods, volcanic eruptions, earthquakes, tsunamis, and other geologic processes. A natural disaster can cause loss of life or property damage, and typically leaves some economic damage in its wake, the severity of which depends on the affected population's resilience, or ability to recover.

3. Let's take a look at some common natural disasters

4. Earthquakes -An earthquake is a violent movement of the rocks in the Earth's crust. -Earthquakes are usually quite brief, but may repeat over a long period of time.

5. Volcanic Eruption -A volcano is a mountain where lava (hot, liquid rock) comes from a magma chamber under the ground. -Most volcanoes have a volcanic crater at the top. When a volcano is active, materials come out of it. The materials include lava, steam, gaseous sulfur compounds, ash and broken rock pieces. -When there is enough pressure, it causes the volcano to erupt. The pressure blows off the top of the volcano. The magma comes out.

6. Tsunami -A tsunami is a series of fast moving waves in the ocean caused by powerful earthquakes or volcanic eruptions. -A tsunami has a very long wavelength. It can be hundreds of kilometers long. -Usually, a tsunami starts suddenly. The waves travel at a great speed across an ocean with little energy loss. -They can remove sand from beaches, destroy trees, toss and drag vehicles, damage houses and even destroy whole towns.

7. Tornado A tornado is a tube of violently spinning air that touches the ground. Wind inside the tornado spins fast, but the actual 'circle' of wind around them is massive. This makes tornadoes very dangerous Tornadoes are especially dangerous to people in cars or mobile homes.

8. The top 10 Natural Disasters of the last 100 years

9. Next class we will talk about how to react when these natural disasters happen