Divergent

__Definition__ Divergent Boundary - Locations where plates are moving away from one another occurring above rising convection. They create ridges and rift valleys.

East Africa, Red Sea, and Iceland are places divergent boundaries occur. __Effects__ Some effects a divergent boundary can have on earth are ridges and rifts. Earthquake activity isn't as strong or deep as around convergent plate boundaris. New ocean floor is made along ridges as magma flows into its crests. The underwater mountain ranges are just as strong as ones that are on land. Underwater ridges are known for volcanic activity along them. The mid-Atlantic ridge is one of the most well known ridges formed by a divergent boundary which reaches from the Arctic Ocean to the southern tip of Africa. The average movement for the Mid-Atlantic ridge is about 2.5 centimeters per year. The two plates that make up the Mid-Atlantic ridge which runs through Iceland is the North American Plate and Eurasian Plate. __Animation Volcanoes Test Questions__ What is the mot well known ridge formed from a divergent boundary? Which two plates make up the Mid-Atlantic Ridge? What are underwater ridges known for? Where is the only continental-continental divergent plate?

__Citations__
 * Divergent Plate Boundaries. Retrieved February 26, 2009, from geology.com Web site: http://geology.com/nsta/divergent-plate-boundaries.shtml
 * Understanding Plate Motions. Retrieved February 26, 2009, from USGS Web site: http://pubs.usgs.gov/gip/dynamic/understanding.html
 * Types of Plates. Retrieved February 27, 2009, from Our Changing Continent Web site: http://platetectonics.pwnet.org/story_tectonics/north_american/types_of_plates.htm
 * Global Volcanism Program. Retrieved February 27, 2009, from Volcanoes of Africa and the Red Sea Web site: http://www.volcano.si.edu/world/region.cfm?rnum=02