1. Birth of a Volcano

2. What Causes Volcanoes? Effects of Plate Tectonics Forces from Within the Earth

3. Plate Tectonics Plate Tectonics, theory that the outer shell of the earth is made up of thin, rigid plates that move relative to each other.

4. Tectonic plates are made of either oceanic or continental crust and the very top part of the mantle, a layer of rock inside the earth. Tectonic Plates

5. A s the plates move, weak areas in the crust are created allowing molten rock, or magma, to well up to the earth’s surface.

6. Forces from Within the Earth

7. Anatomy of a Volcano

8. Where Volcanoes Occur

9. Changes Caused by Volcanoes Physical Changes to the Earth Environmental Changes

10. Physical Changes New Land Islands in the Ocean Mountains and Plains

11. Environmental Changes Initial impact destroys living environment Long-term effects slow recovery new ecosystem

12. Important Terms Plate Tectonics Tectonic Plates Continental Crust Ocean Crust Lithosphere Mantle “Ring of Fire”

13. Volcano Quiz 1. What are tectonic plates? 2. Where do most volcanoes occur? 3. What is magma? 4. What is a “hot spot”? 5. Name one physical change and one environmental caused by volcanoes.

14. References http://pubs.usgs.gov/publications/text/dynamic.html This dynamic earth; example and sources http://encarta.msn.com/find/Concise.asp?ti=00C48000 Encarta – brief descriptions of tectonics, plates and related http://library.thinkquest.org/17457/english.html Volcanoes web page http://www.thinkquest.org/library/lib/site_sum_outside.ht ml?tname=17457&url=17457/http://www.thinkquest.org/library/lib/site_sum_outside.ht ml?tname=17457&url=17457/ Thinkquest activities, volcanoes