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Volcano • Weak spot in the crust where magma comes to the surface Volcanoes Form under the ocean at mid-Atlantic ridge or subduction zones vpand under the ocean(more than on land) Magma – forms inside a volcano – molten mixture of rock, gases and water from the mantle Lava • magma that forms outside a volcano • turns into volcanic rock when cooled Constructive Force • Volcanic activity is a constructive force – adds new rock – adds new crust Ring of Fire -abundance of volcanoes that rim the Pacific Ocean Island arcs – Islands formed by a string of volcanoes – Follows the curve of an ocean trench • Ex- Japan, Caribbean, New Zealand, Aleutian islands(Alaska) Notice the Arc Volcanologists –study volcanoes Hot Spot volcanoes • • • • • Hot spot-area where magma from deep within the mantle melts through the crust like a blow torch Often lies in the middle of plates far from boundaries Gradually forms volcanic mountains Ex- ocean, Hawaiian islands in the Pacific Ex- land Yellowstone National Park, Wyoming http://geology.wwu.edu/dept/fa culty/hirschd/courses/2012/fall/ 101/lectures/media/Lecture04/ HotSpot.swf https://www.classzone.com/boo ks/earth_science/terc/content/vi sualizations/es0904/es0904page 01.cfm?chapter_no=visualization Hot Spot Volcanoes • Young volcanic mountains are found closer to the hot spot • Older volcanic mountains are found further away from the hot spot • Hot spots are found in the MIDDLE of plates • The hot spots stay still while the plate moves. • Connection-rock and the mid Atlantic Ridge Arch Islands • Found near boundaries • Found near trenches
