Global Volcanoes http earthref orgSCC Scripps Classroom Connection
Global Volcanoes http: //earthref. org/SCC Scripps Classroom Connection
Volcanoes occur at: 1. Hotspots 2. Plate Boundaries -Convergent (subduction zones) -Divergent Where do volcanoes occur? http: //earthref. org/SCC Scripps Classroom Connection
Hotspots §Spot on Earth with volcanism Hawaii §Can occur in the middle of tectonic plates §Hotspots don’t move §Tectonic plates move over hotspots §Makes a chain of volcanoes, like Hawaii What are hotspots? http: //earthref. org/SCC Scripps Classroom Connection
Ocean Hotspots §Shield volcanoes, Hawaiiian Islands §Fast moving, basaltic lava §Effusive §Stratovolcanoes, Canary Islands §Alternating lava and ash §Explosive Continental hotspots §Explosive §Yellowstone Caldera, Wyoming http: //earthref. org/SCC Hotspot volcanoes Scripps Classroom Connection
Subduction Zone Volcanoes § Most major volcanoes found near subduction zones § Stratovolcanoes § Most dangerous Two different types: 1. Ocean-Ocean 2. Ocean-Continent http: //earthref. org/SCC Subduction Zones Scripps Classroom Connection
Ocean-Ocean §Island Volcanic Arcs §Japan §Aleutian Islands, Alaska Ocean-Ocean Subduction Volcanoes http: //earthref. org/SCC Scripps Classroom Connection
Ocean-Continent §Continental Volcanic Arcs §Andes Mountains, South America §Cascades, N. W. United States Ocean-Continent Subduction Volcanoes http: //earthref. org/SCC Scripps Classroom Connection
Tectonic Spreading Centers Under the ocean §Mid-ocean ridges On Land §Continental rifts Almost continuous volcanism Create new oceanic crust http: //earthref. org/SCC Spreading Centers Scripps Classroom Connection
Mid-Ocean Ridge Volcanoes §Volcanoes form on fissures parallel to the ridge axis §Hundreds of volcanoes along each ridge, nearcontinuous volcanism §Erupt basalt §Create new oceanic crust Mid-Ocean Ridge Volcanoes http: //earthref. org/SCC Scripps Classroom Connection
Global Volcano Conclusions ● Most volcanoes occur at plate boundaries: 1. Subduction zones 2. Mid-ocean ridges ● Some volcanoes occur at hotspots: 1. Ocean floor 2. Continental http: //earthref. org/SCC Scripps Classroom Connection
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