volcanic eruptions
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1.new terms 2.What is a volcano? 3.How and why do volcanoes erupt? 4.Explosive Eruptions 5.Parts of Volcanoes 6. subduction 7.how are they formed 8.volcanic activity levels 9. types of volcanos 10.SHIELD VOLCANO 11. Mt. Kilauea 12.CINDER CONE VOLCANO 13.COMPOSITE VOLCANO 14.Volcanoes around the world 15.Multiple Eruption volcanoes made by :RATIKA,Delhi,India
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volcanic eruptions
- 2. GLOSSARY RATIKA DELHI INDIA Bomb – a lump of rock thrown out in an eruption Crater – a deep hollow at the top of a volcano Crust – The top layer of the Earth Eruption – the release of gases, magma and rock from a volcano Lava – melted rock that flows down the volcano Magma – melted rock inside the Earth Molten – melted, liquid Vent – a crack on the side of a volcano where magma can escape
- 3. What is a volcano? vent cone conduit RATIKA DELHI INDIA A volcano is a vent or 'chimney' that connects molten rock (magma) from within the Earth’s crust to the Earth's surface. • The volcano includes the surrounding cone of erupted material. magma chamber •
- 4. How and why do volcanoes erupt? • • • • RATIKA DELHI INDIA Hot, molten rock (magma) is buoyant (has a lower density than the surrounding rocks) and will rise up through the crust to erupt on the surface. – Same principle as hot air rising, e.g. how a hot air balloon works When magma reaches the surface it depends on how easily it flows (viscosity) and the amount of gas (H2O, CO2, S) it has in it as to how it erupts. Large amounts of gas and a high viscosity (sticky) magma will form an explosive eruption! – Think about shaking a carbonated drink and then releasing the cap. Small amounts of gas and (or) low viscosity (runny) magma will form an effusive eruption – Where the magma just trickles out of the volcano (lava flow).
- 5. Explosive Eruptions • Three products from an explosive eruption – Ash fall – Pyroclastic flow – Pyroclastic surge Pyroclastic flows on Montserrat, buried the capital city.
- 6. Parts of Volcanoes Crater Lava Side Vent Main Vent RATIKA DELHI INDIA
- 10. RATIKA DELHI
- 15. ACTIVE VOLCANOES-which are likely to erupt at any moment. DORMANT VOLCANOES-which lie dormant for centuries, but then erupt violently and silently. EXTINCT VOLCANOES -no longer likely to erupt. RATIKA DELHI INDIA
- 16. Types of Volcanoes Types of Volcanoes Shield Volcano Composite Volcano Cinder Cone Volcano Kilauea, Hawaii Mt. St. Helens, Washington Parícutin, Mexico RATIKA DELHI INDIA
- 17. SHIELD VOLCANO RATIKA DELHI INDIA Shield volcanoes can span across hundreds of miles and they can be huge vertically that they can reach the clouds of earth very easy. Shield volcanoes have a slow slope and consist of frozen lava after it is hardened. Shield volcanoes almost always have large craters at their summit.
- 19. CINDER CONE VOLCANO Cinder cone volcanoes consist of mostly loose, grainy cinders and have very little to no lava. Cinder cone volcanoes are normally small about a miles span and about one thousand feet vertically. Cinder cone volcanoes have fairly steep slopes and normally have RATIKA a small crater at the top. DELHI INDIA
- 21. COMPOSITE VOLCANO Composite volcanoes have another name called “Strato Volcanoes.” Composite volcanoes consist of lava that is mixed with sand or gravel which in turn creates cinders or volcanic ash. RATIKA DELHI INDIA
- 23. Volcanoes around the world RATIKA DELHI INDIA Volcanoes per Continent Australia South America North America Asia Europe So e ro p Eu ia As Af r An ica ta rc tic a ut h Au st ra l i Am a N er or ic th Am a er ica 250 200 150 100 50 0 Africa Antarctica
- 24. GRAPHICAL PRESENTATION Volcanoes Around the world South America 11% Africa 13% North America 27% Europe 4% Antarctica 2% Asia 37% Australia 6% RATIKA DELHI INDIA
- 25. World Map of Volcanoes RATIKA DELHI INDIA
- 26. Multiple Eruption volcanoes KilaueaHawaii VesuviusItaly Mt. St. HelenWashington March 2005 March 18, 1944 September 23, 2004 November 2000 79 AD May 18, 1980 RATIKA DELHI INDIA