Volcanoes

1. Volcanoes Created by Jim Birney, Education Adviser, Fife Education Service, Scotland. Images marked USGS are public domain images from the Unites States Geological Service.Created by Jim Birney, Education Adviser, Fife Education Service, Scotland. Images marked USGS are public domain images from the Unites States Geological Service.

2. Volcanoes To add introduction followed by reference to converging and diverging plates and onto Pangea and the movement of plates. Include a hot link to Volcanic and Seismic Activity since 1960 and web cams sites.To add introduction followed by reference to converging and diverging plates and onto Pangea and the movement of plates. Include a hot link to Volcanic and Seismic Activity since 1960 and web cams sites.

3. Volcanoes: why they occur What causes a volcano? Different types of volcanoes and famous eruptions The different layers of the Earth Plate Tectonics What causes a volcano? The different layers in the Earth, Plate Tectonics, What causes a volcano? The different layers in the Earth, Plate Tectonics,

4. Volcanoes: what causes a volcano The earth is unstable. Below the surface of the earth’s crust there is movement, known as plate tectonics. The energy generated can cause molten rock to seek a path to the surface. The force of molten rock or explosive material forms a volcano. Place a link to the earth’s crust where a diagram explains the four layers and to slides on plate tectonics.Place a link to the earth’s crust where a diagram explains the four layers and to slides on plate tectonics.

5. The lava begins to flow There is lots of energy released Gas and ash explodes into the air and lava flows down the sides of the volcano.

6. Why is the volcano forming? 1 Earth movements in the Crust causes the molten rock to seek ways to reach the surface The pressure causes the molten rock to find a route upwards.

7. Why is the volcano forming? 2 Once the surface is breached there could be explosions and clouds of ash and volcanic bombs. This depends on how much gas is trapped within the molten rock.

8. Why is the volcano forming? 3 On other occasions the molten rock has more liquid than gas and the lava flows out onto the surface covering a large area.

9. Why is the volcano forming? 4 If the molten rock doesn’t reach the surface it will cool down to form hard rock, known as granite. Over millions of years the softer rocks are eroded to reveal the granite.

10. Different types of volcano Shield Composite Cinder Need to check on the names used nowadays.Need to check on the names used nowadays.

11. Shield Volcano Very slow, but easily flowing lava covering a wide area forms shield volcanoes as in the Hawaiian islands. This happens where an oceanic plate moves slowly over a hot spot in the earth’s crust.

12. Composite This type has alternate layers of ash and lava. Sometimes there can be different layers of lava on top of each other, but with years in between eruptions.

13. Cinder Volcano

14. Cinder Volcanoes (2) There are some famous examples Vesuvius (AD 79) Krakatoa (1883) Mount Pelee (1902) Mount St. Helens (1980)

15. Vesuvius, Italy AD79 A famous eruption which destroyed the Roman town of Pompeii. In recent years the ash has been removed to reveal the town and its occupants. This is evidence of how such eruptions take people by surprise.

16. Krakatoa, Indonesia, 1883 This eruption caused the island of Krakatoa to blow apart and spread ash around the world. Map of Martinique would be useful.Map of Martinique would be useful.

17. Mount Pelee, Martinique This volcano erupted in 1902 killing almost 30,000 people on the island of Martinique in the Caribbean Sea. Such a high number was the result of the sudden explosion of ash in a fast-moving cloud (160 km per hour) with gases, the speed overwhelming the people. Map of Martinique would be useful.Map of Martinique would be useful.

18. Before the eruption geologists had time to study the volcano, but even they were surprised by the speed and ferocity of the event. Mount St. Helens, Washington, USA To add a link to pages describing this eruption in more detail or some noted leading onto a web site.To add a link to pages describing this eruption in more detail or some noted leading onto a web site.

19. The blast caused damage over several miles. Mount St Helen’s Map To add a link to pages describing this eruption in more detail or some noted leading onto a web site.To add a link to pages describing this eruption in more detail or some noted leading onto a web site.

20. Inside the earth There are four layers Need to have a diagram highlighting the different layers by colour or by arrows.Need to have a diagram highlighting the different layers by colour or by arrows.

21. Plate Tectonics (1) To add introduction followed by reference to converging and diverging plates and onto Pangea and the movement of plates. Include a hot link to Volcanic and Seismic Activity since 1960 and web cams sites.To add introduction followed by reference to converging and diverging plates and onto Pangea and the movement of plates. Include a hot link to Volcanic and Seismic Activity since 1960 and web cams sites.

22. Plate Tectonics (2)

23. Plate Tectonics (3) There are four variations linked to volcanic activity Converging plates Diverging plates Transform plates Hot Spots where an oceanic plate is very thin To add introduction followed by reference to converging and diverging plates and onto Pangea and the movement of plates. Include a hot link to Volcanic and Seismic Activity since 1960 and web cams sites.To add introduction followed by reference to converging and diverging plates and onto Pangea and the movement of plates. Include a hot link to Volcanic and Seismic Activity since 1960 and web cams sites.

24. Plate Tectonics - Converging Plates Plates moving towards each other results in one plate sliding below the other. When this happens the rock are melted by the very high pressure and the molten rock forces its way upwards with volcanic activity if it reaches the surface. To add introduction followed by reference to converging and diverging plates and onto Pangea and the movement of plates. Include a hot link to Volcanic and Seismic Activity since 1960 and web cams sites.To add introduction followed by reference to converging and diverging plates and onto Pangea and the movement of plates. Include a hot link to Volcanic and Seismic Activity since 1960 and web cams sites.

25. Plate Tectonics - Converging Plates (2) Where an oceanic plate collides with a continental plate it sinks and there is a lot of volcanic activity. To add introduction followed by reference to converging and diverging plates and onto Pangea and the movement of plates. Include a hot link to Volcanic and Seismic Activity since 1960 and web cams sites.To add introduction followed by reference to converging and diverging plates and onto Pangea and the movement of plates. Include a hot link to Volcanic and Seismic Activity since 1960 and web cams sites.

26. Plate Tectonics - Converging Plates (3) Volcanic eruptions over the past 4000 years in western U.S.A.

27. Plate Tectonics – Diverging Plates To add introduction followed by reference to converging and diverging plates and onto Pangea and the movement of plates. Include a hot link to Volcanic and Seismic Activity since 1960 and web cams sites.To add introduction followed by reference to converging and diverging plates and onto Pangea and the movement of plates. Include a hot link to Volcanic and Seismic Activity since 1960 and web cams sites.

28. Plate Tectonics – Transform Plates This is where two plates slide past each other. The plates rub against each other and, when the tension builds up, the pressure is released by an earthquake. Some of these result in volcanic activity, but this is less common. To add introduction followed by reference to converging and diverging plates and onto Pangea and the movement of plates. Include a hot link to Volcanic and Seismic Activity since 1960 and web cams sites.To add introduction followed by reference to converging and diverging plates and onto Pangea and the movement of plates. Include a hot link to Volcanic and Seismic Activity since 1960 and web cams sites.

29. Plate Tectonics - Hot Spots To add introduction followed by reference to converging and diverging plates and onto Pangea and the movement of plates. Include a hot link to Volcanic and Seismic Activity since 1960 and web cams sites.To add introduction followed by reference to converging and diverging plates and onto Pangea and the movement of plates. Include a hot link to Volcanic and Seismic Activity since 1960 and web cams sites.

30. Hot Spot Formation In 1963 a Canadian scientist (J Wilson) studied the islands running from Hawaii across the Pacific Ocean almost to the coast of Japan.

31. Hot Spot Formation (2) The oceanic plate is very thin and a magma chamber is close to the surface. It breaks through releasing lava onto the seabed which grows in time to form seamounts (underwater mountains) and islands if the volcano is above sea level.

32. Note the move from the younger, active volcano to the older, extinct volcanoes. Hot Spot Formation (3)

33. Other hotspots on the ocean floor. The lines show the boundaries of different tectonic plates. Hot Spot Formation (4)

34. Volcanoes: where they occur Although they appear all over the world their location can be linked to plate tectonics. Some active zones are Pacific Ring of Fire Southern Europe East Africa Mid Oceanic Ridges (Atlantic) Place a link to the earth’s crust where a diagram explains the four layers and to slides on plate tectonics.Place a link to the earth’s crust where a diagram explains the four layers and to slides on plate tectonics.

35. Volcanoes: where they occur World map showing the pacific ring of fire, Southern Europe, Mid Atlantic Ridge, eat Africa Rift Valley. Display in animated sequence.World map showing the pacific ring of fire, Southern Europe, Mid Atlantic Ridge, eat Africa Rift Valley. Display in animated sequence.

36. Volcanoes: what effect they have Volcanoes are a natural hazard yet in many parts of the world there are a large number of people living very close to active volcanoes. In other areas extinct volcanoes have been used by people and wildlife in a number of ways.

37. Volcanoes: what effect they have Let’s look at some effects:- Hazards faced during an eruption Why people live close to active volcanoes How extinct volcanic landscapes have been used.

38. Hazards Water and sulpher gas mix to create fumaroles. Add features and arrows, first the underground, then ash related, lava related and, finally landslides and lava domes.Add features and arrows, first the underground, then ash related, lava related and, finally landslides and lava domes.

39. If you look at a world map of active volcanoes you will notice that they are found in densely populated countries such Japan, Indonesia, and Italy. So why would the people live there? Why people live close to active volcanoes (1)

40. Why people live close to active volcanoes (2) Volcanic materials ultimately break down and weather to form some of the most fertile soils on Earth, cultivation of which has produced abundant food and fostered civilizations. -- Excerpt from: Tilling, 1985, Volcanoes: USGS General Interest Publication

41. Other benefits Industry benefits from using aggregates of igneous rocks in road building, gravel for paths, granite for houses and other chemicals for cleaning agents. Mineral veins have encouraged mining of precious metals.

42. How extinct volcanic landscapes have been used. There are many parts of the world no longer near a plate boundary, but when they were volcanoes formed on the surface and igneous rock spread out into the existing rocks forming sills, dykes, laccoliths and batholiths.

43. Volcanoes: Other Features Choose from

44. Parts of a Volcano Typical parts of a volcano showing a composite volcano with layers of ash and lava. Need a good, clear diagram for this slide and for a later slides used as a revision exercise. Add the names in text boxes and have them zoom out at the correct place.Need a good, clear diagram for this slide and for a later slides used as a revision exercise. Add the names in text boxes and have them zoom out at the correct place.

45. Geysers A geyser is a hot spring which sends extremely hot water bursting out of the earth. Sometimes there are spectacular fountains created. In the Yellowstone National Park in the U.S.A. the geysers are very active.

46. Geysers

47. Gemstones Think of diamonds, emeralds and other stones and you may be surprised to know that these precious gems are the result of chemical reactions caused by the great heat associated with molten rock mixing with other rocks. When the rock cools crystals form, often in gas bubbles called geodes.

48. Mineral Veins Igneous activity can form new chemical compounds which are valuable to mankind. The hot magma melts the surrounding rock and when it cools the minerals separate out into mineral veins. Cornwall was famous for its tin mines over a century ago.

49. Basalt and Granite Basalt has cooled down quickly on the surface or on the sea bed and is broken down easily. Granite is a very hard rock as it cools slowly underground. It is used in buildings. Aberdeen is known as the Granite City.

50. Calderas Most volcanoes have a crater near their summit but a caldera is a much larger feature. It is formed when the magma deep down moves causing the ground to collapse down the vent into the space.

51. Volcanoes: Exercise 1 Use the list below to label the diagram. Lava Eruption Cloud Acid Rain Magma Bombs Mud flow Lava Dome Landslide Fumaroles Ground Water Pyroclastic Flow

52. Volcanoes: Exercise 2 Find out Why minerals are separated into veins when the molten rock cools down? How a geode forms. Why converging plates result in more explosive volcanoes than a diverging plate. Why earthquakes and volcanoes are found in the same locations across the world. World map showing the pacific ring of fire, Southern Europe, Mid Atlantic Ridge, eat Africa Rift Valley. Display in animated sequence.World map showing the pacific ring of fire, Southern Europe, Mid Atlantic Ridge, eat Africa Rift Valley. Display in animated sequence.

53. Volcanoes: Exercise 3 There are a number of exercises found on the US Geological Website. Just click on http://interactive2.usgs.gov/learningweb/teachers/volcanoes.htm World map showing the pacific ring of fire, Southern Europe, Mid Atlantic Ridge, eat Africa Rift Valley. Display in animated sequence.World map showing the pacific ring of fire, Southern Europe, Mid Atlantic Ridge, eat Africa Rift Valley. Display in animated sequence.

54. Volcanoes: Useful Websites 1 There are a large number of websites devoted to a study of volcanoes. Some are listed here to get you started. World map showing the pacific ring of fire, Southern Europe, Mid Atlantic Ridge, eat Africa Rift Valley. Display in animated sequence.World map showing the pacific ring of fire, Southern Europe, Mid Atlantic Ridge, eat Africa Rift Valley. Display in animated sequence.

55. Volcanoes: Useful Websites 2 Plate Tectonics animation http://www.ucmp.berkeley.edu/geology/tectonics.html     Plate tectonics explained – quite advanced http://www.seismo.unr.edu/ftp/pub/louie/class/100/plate-tectonics.html   Volcanic definitions. http://www.hcrhs.hunterdon.k12.nj.us/science/ptech.html

56. Credits