By Antony Spicer

2. By Antony Spicer n a t u d a i l s a s t e r s

3. contents

4. contents pictures volcanoes n a t u a l i d s a s t e r s quiz There are around 1510 'active' volcanoes in the world. We currently know of 80 or more which are under the oceans. Over half of the world’s volcanoes arise in a belt around the Pacific Ocean called the Ring of Fire. When magma erupts through the earth's surface it is called lava. When two plates collide, one section slides on top of the other, the one beneath is pushed down. Magma is squeezed up between two plates. Between the Earth's crust and the mantle is a substance called magma which is made of rock and gases. The Earth's crust is made up of huge slabs called plates, which fit together like a jigsaw puzzle. These plates sometimes move. A volcano is a landform usually a mountain where molten rock erupts through the surface of the planet. In simple terms a volcano is a mountain that opens downward to a pool of molten rock magma below the surface of the earth. It is a hole in the Earth from which molten rock and gas erupt. Lava is liquid rock (magma) that flows out of a volcano. Fresh lava ranges from 1,300° to 2,200° F (700° to 1,200° C) in temperature and glows red hot to white hot as it flows.

5. contents pictures twisters n a t u a l i d s a s t e r s quiz A tornado is a rapidly spinning tube of air that touches both the ground and a cloud above. Tornadoes are sometimes called twisters. Not all tornadoes are visible but their high wind speeds and rapid rotation often form a visible funnel of condensed water. The Fujita Scale is a common way of measuring the strength of tornadoes. The scale ranges from F0 tornadoes that cause minimal damage through to F5 tornadoes which cause massive damage. Most tornadoes have wind speeds less than 100 miles per hour (161 kilometres per hour). Extreme tornadoes can reach wind speeds of over 300 miles per hour (483 kilometres per hour). Most tornadoes travel a few miles before exhausting themselves. Extreme tornadoes can travel much further, sometimes over 100 miles (161kilometres). The Tri-State Tornado that travelled through parts of Missouri, Illinois and Indiana in 1925 left a path of destruction over 219 miles (352 kilometres) long. The Tri-State Tornado was the deadliest tornado in US history, killing 695 people. The USA averages around 1200 tornadoes every year, more than any other country. The majority of these tornadoes occur in a geographically unique area nicknamed ‘Tornado Alley’. US States most often hit by tornadoes include Texas, Kansas, Oklahoma and Florida.

6. contents pictures Forest fires n a t u a l i d s a s t e r s quiz Forest fires are a crucial part of their lifecycle. Fires take warm air up into the tops of the trees, which dries the cones and makes them split, allowing the seeds to pop out. In the United States they used to have a policy of putting out all forest fires. However, in the 1960s they realised that there were no new giant sequoia trees growing. They grow in the Western USA and have a larger diameter than any other tree species in the world. When a heat wave or drought dries out the plants in an area, a fire can start and spread quickly. Fires can be accidental or they can be caused by arson or even lightning strikes. Wild fires take place all over the world. Major fires happen every few years in the forests of the United States and Indonesia, and in the bush in Australia. Also, burning leaves and branches can get blown ahead of the main fire causing smaller fires to start.

7. contents pictures tsunami n a t u a l i d s a s t e r s quiz A tsunami is a series of sea waves caused by an underwater earthquake, landslide, or volcanic eruption. More rarely, a tsunami can be generated by a giant meteor impact with the ocean. When the ocean is deep, tsunamis may be less than a foot high on the ocean’s surface, can travel at speeds up to 500 mph without being noticed and cross the entire ocean in less than a day. Flooding can reach land 1000 feet (300 meters) from the coastline and the dangerous waves have enough force to lift giant boulders, flip vehicles, and demolish houses In 2004, the Indian Ocean tsunami was caused by an earthquake that is thought to have had the energy of 23,000 atomic bombs. Within hours of the earthquake in 2004, killer waves radiating from the epicentre slammed into the coastline of 11 countries, damaging countries from east Africa to Thailand. By the end of the day, the tsunami had already killed 150,000 people. The final death toll was 283,000.

8. volcanoes

9. twisters

10. Forest fires

11. tsunami

12. 1. Which of the following is NOT considered a natural disaster? hurricane Volcano All of these Earthquake

13. 2. A Volcano is classified as dormant, extinct or ______ None of the above Angry Friendly Active

14. 3. Name the natural disaster that is considered the most violent? flood Tornado Volcano Rainbow