GWBN+3.1

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=Vocabulary=


 * volcano**- a weak spot in crust where molten material, or magma, comes to the surface


 * magma-** a molten mixture of rock forming substances


 * lava**- magma that reaches the surface


 * Ring of Fire**- a major volcanic belt


 * island arc**- a string of islands created by erupting volcanoes

= = =Outline=
 * hot spot**- an area where magma from deep within the mantle melts through the crust like a blowtorch

=T= Volcanoes and Plate Tectonics= To go back to the top, click here
 * ====**What is a Volcano?**====
 * weak spot in crust
 * spews out lava
 * volcanic activity adds rock to land
 * ====Location of Volcanoes====
 * 600 active volcanoes
 * more lie beneath the sea
 * volcanoes occur in belts
 * major belt= Ring of Fire
 * volcanic belts form along boundaries of Earth's plate
 * crust weak fracture at boundaries
 * most volcanoes occur along diverging plate boundaries
 * ====Volcanoes at Diverging Plate Boundaries====
 * form along mid- ocean ridge= diverging plate boundary
 * along ridge, lava pours out of cracks on ocean floor
 * =Volcanoes at Converging Boundaries=
 * many volcanoes form near plate boundaries
 * oceanic crust returns to the mantle in boundaries
 * the crust melt= forms magma, rises toward surface
 * magma erupts as lava, and volcanoes formed
 * volcanoes occur on....
 * islands
 * near boundaries
 * older, denser, lower plate creates deep ocean trench
 * lower plate sinks into asthenosphere, and melts
 * melted plate forms magma
 * magma seeps upward through crust's cracks
 * magma breaks through ocean floor, creating volcanoes
 * volcanoes create string of islands= island arc
 * island arc's curve echo's deep ocean trench
 * major island arc= New Zealand, Japan, Indonesia, Carribean Islands, etc.
 * Subduction occurs where edge of continental plate collides w/ oceanic plate
 * collisions produced Andes Mt. volcanoes
 * ===Hot Spot Volcanoes===
 * some volcanoes formed from hot spots
 * hot spot= area where magma from deep within the mantle melts through crust
 * hot spots lie in middle of of continental or oceanic plates
 * volcanoes from hot spots not from subduction
 * hot spots also can form under continents