4. At a constructive plate boundary, two plates move apart. As the two plates move apart, magma rises up to fill the gap. This causes volcanoes at this type of boundary. However, since the magma can escape easily at the surface the volcano does not erupt with much force. E.g. Mid-Atlantic Ridge. Constructive Plate Boundary
5. A destructive plate boundary is found where a continental plate meets an oceanic plate. The oceanic plate subducts (sinks) under the continental plate because it is denser. Friction melts the plates. This melted plate is now hot, magma. If it reaches the surface, the liquid rock forms a volcano. E.g. Nazca and South American Plate Destructive Plate Boundary
6. Conservative plate boundaries exist where two plates slide past each. No volcanoes are found along these plate boundaries, but earthquakes do occur. E.g. San Andreas Fault, San Francisco Conservative Boundary
7. Collision boundaries occur when 2 continental plates move together. This causes the material between them to buckle and rise up, forming fold mountains. E.g. Himalayas Collision Boundary
8. STRUCTURE OF A VOLCANO Steam, Ash, Gas Volcanic Bombs Crater Secondary Cone Lava Flow Vent Magma Chamber
14. Montserrat Case Study Montserrat is found in the Caribbean and is part of the Leeward Islands. It is part of a island arc and was formed by volcanic eruptions. North American Plate
15. After 2 years of rumbling a huge eruption occurred on July 25 1997. In July 1995 the dormant volcano of Soufriére Hills started to rumble back to life. Montserrat is a Caribbean island famous for beautiful beaches and sea. Background Information
16. Underneath Montserrat the North American plate is slowly being forced under the Caribbean plate. The Soufrière Hills Volcano produces a thick sticky lava. Montserrat is situated on a destructive plate boundary. The lava was thick and it built up at the top of the volcano in a dome until it collapsed. Causes of the Eruption
17. Airport was evacuated and closed. Capital City (Plymouth) almost totally destroyed and evacuated. 19 people killed and many more injured. A total of at least 4 square kilometres of land was covered by the pyroclastic flows and surges. People evacuated to the north of the island. Rich farmland destroyed by mudflows and covered by layers of ash. Destroyed between 100 -150 houses. About 8000 residents left the island to live somewhere safer. The southern part of the island is off limits and people are fined if they are found there. Effects of the Eruption
18. INSTRUCTIONS There are 10questions for you to have a go at – as you work through the slides, write down the number of the question and your answer. At the end of the 10 questions – there are slides with the correct answers on for you to check your answers – GOOD LUCK!
19. Question 1. Which of the following is an example of a volcanic eruption? Montserrat – 1997 San Francisco – 1989 Kobe – 1995 Tokyo - 1919
21. Question 3. Re-arrange the following to give the correct order explaining the eruption of a volcano friction between plates and heat from the earth causes melting of the oceanic plate two plates move towards each other subduction of the lighter oceanic plate occurs molten magma rises and erupts
22. Question 4. A constructive boundary is.. where two plates move side by side where two plates move together where two plates move away from each other.
23. Question 5. A collision boundary is where an oceanic and a continental plate meet two continental plates meet two oceanic plates meet two plates move away from each other
24. Question 6. At this boundary two plate move apart from each other collision boundary constructive boundary destructive boundary conservative boundary
25. Question 7. At this boundary two plates of continental crust meet collision boundary constructive boundary conservative boundary destructive boundary
26. Question 8. Here an oceanic and continental plate move together.. destructive Boundary constructive boundary conservative boundary collision boundary
27. Question 9. The outer layer of the earth is called the.. crust mantle core
28. Question 10. This process occurs where two plates meet together.. precipitation subduction transpiration divergence
29. Answers Slide Question 1. Which of the following is an example of a volcanic eruption? Montserrat – 1991 San Francisco – 1989 Kobe – 1995 Tokyo - 1919
31. Question 3. Re-arrange the following to give the correct order explaining the eruption of a volcano Answers Slide friction between plates and heat from the earth causes melting of the oceanic plate two plates move towards each other subduction of the lighter oceanic plate occurs molten magma rises and erupts 3 1 2 4
32. Answers Slide Question 4. A constructive boundary is.. where two plates move side by side where two plates move together where two plates move away from each other.
33. Answers Slide Question 5. A collision boundary is where an oceanic and a continental plate meet two continental plates meet two oceanic plates meet two plates move away from each other
34. Answers Slide Question 6. At this boundary two plate move apart from each other collision boundary constructive boundary destructive boundary conservative boundary
35. Answers Slide Question 7. At this boundary two plates of continental crust meet collision boundary constructive boundary conservative boundary destructive boundary
36. Answers Slide Question 8. Here an oceanic and continental plate move together.. destructive Boundary constructive boundary conservative boundary collision boundary
37. Answers Slide Question 9. The outer layer of the earth is called the.. crust mantle core
38. Answers Slide Question 10. This process occurs where two plates meet together.. precipitation subduction transpiration divergence
