1. The Ring of Fire A Presentation by Danny Jensen

2. What is… The Ring of Fire?  The Ring of Fire is an arc of volcanic and seismic activity that is located on the border of the Pacific Plate

3. What is… The Ring of Fire? (cont.)  The Ring of fire is a chain of volcanoes that rings around the Pacific plate  This ring contains 452 volcanoes  Nearly 75% of all volcanoes in the world are located on this ring

4. Volcanoes… How do they work?  Most volcanoes that are formed on land are a direct result of tectonic plates coming together where one subducts under the other into the mantle.  This causes an increase in both temperature and pressure in the mantle

5. Volcanoes… How do they work? (cont.)  When both temperature and pressure increase, the rock inside the mantle melts and turns into liquid rock, or magma  Pressure is built up until the magma is forced to release onto the Earth’s surface  Volcanoes form from multiple releases of magma on the Earth’s surface

6. Formation of the Volcano  When the magma erupts at the Earth’s surface, it creates lava flows and ash deposits that layer the volcano’s formation.  Magma starts in the reservoir, builds its way up the throat as pressure increases, and finally erupts through the vent and flows down the side of the volcano, creating multiple layers of ash and magma

8. The Cascades Range  A key feature on this range is Mt. St. Helens  Because of the magma that dwells in subduction zones is very viscous (resistant to flow), eruptions are very violent when they explode.

9. Earthquakes  Another key feature of The Ring of Fire is both minor and major earthquakes.  Earthquakes can occur from three different tectonic plate activities:  Convergent  Occurs at a convergent fault line when two plates collide  Divergent  Two plates separate. Magma rises from the mantle to fill the gap or one plate slides down to fill the space.  Transform  When two plates rub against each other and slide in opposite directions.

10. Earthquake & Volcano Correlation  Often, when two plates collide, one of the plates submerges beneath the other. It is this subduction that creates the temperature and pressure increase that forms magma and volcanoes.  Deep ocean trenches and huge earthquakes are also created along these fault-lines

11. Formation of other Geologic Landmarks  The Andes Mountains is a direct result of the Ring of Fire’s activities  The Andes were created from the Nazca plate being pushed under the South American Plate.

12. Recent Activity  August 26/27, 1883: The volcano, Krakatoa, in the Indian Ocean erupts. It kills nearly 40,000 people as tsunami waves crash into Java and Sumatra and are felt as far away as England.  May 18, 1980: Mount St. Helens in southwest Washington state erupts, killing 57. The eruption was triggered by a 5.1 magnitude earthquake.  June 9, 1991: Mount Pinatubo, 80 km north of Manila, erupts. It kills over 700 and destroys 200,000 buildings.

13. Bibliography  Univ. of Delaware,. N.p.. Retrieved from http://www.ceoe.udel.edu/extreme2001/geology/ringoffire.html  The New York Times Company. (n.d.). Retrieved from http://geography.about.com/library/faq/blqzringoffire.htm http://geography.about.com/library/faq/blqzringoffire.htm  Svitil, K. (n.d.). Retrieved from http://www.pbs.org/wnet/savageearth/hellscrust/html/sidebar3.ht ml http://www.pbs.org/wnet/savageearth/hellscrust/html/sidebar3.ht ml  Unknown. (n.d.). Retrieved from http://www.angelfire.com/sc3/popocatepetl/page2.html http://www.angelfire.com/sc3/popocatepetl/page2.html  Unknown. (n.d.). Retrieved from http://library.thinkquest.org/03oct/00758/en/disaster/earthquake/t ectonics.html http://library.thinkquest.org/03oct/00758/en/disaster/earthquake/t ectonics.html