Volcano

1. Volcano How and Where Formed Magma and Erupted Materials Volcanic Landforms Created by C. Ippolito April 2009

2. Where Volcanoes Form • Subduction Boundaries • Cascade Mtns • Mariana Islands • Divergent Boundaries • Iceland • Hot Spots • Hawaiian Islands Created by C. Ippolito April 2009

3. Magma Types • Basaltic Magma • rifts, ocean hot spots • Kilauea • Andesitic Magma • subduction boundaries • Mount St. Helens • Rhyolitic Magma • continental hot spots • Yellowstone Caldera Created by C. Ippolito April 2009

4. Lava Flows • Basaltic Lava Flows • (low silica) • very fluid, fast moving • pahoehoe flow – twisted ropes • viscous, slow moving • aa flow – sharp edges/projections • Underwater Lava Flows • cools more quickly • pillow lava Created by C. Ippolito April 2009

5. Materials From Eruption • Gases • concentration varies • can effect “eruption explosions” • composition varies • carbon dioxide – odorless • sulfur compound – pungent odor “burn” • Pyroclastic Materials • gases and solid fragments released by a volcano Created by C. Ippolito April 2009

6. Pyroclastic Materials • pyroclastics • particles ejected by expanding gases in magma • vary by size • ash • welded tuff • pumice • lapilli • blocks • bombs Created by C. Ippolito April 2009

7. Volcanic Landforms • Shield Volcano • lava builds up in layers • broad base, gentle slope • Mauna Loa • Cinder Cone Volcano • molten lava thrown from vent • Capulin • Composite Volcano • layers formed from eruptions • Mount St. Helens • Mount Shasta Created by C. Ippolito April 2009

8. Volcanic Landforms (con’t) • Caldera • Large crater shaped basin formed when top of volcano collapses • Crater Lake • http://earthsci.org/education/teacher/basicgeol/igneous/igneous.html Created by C. Ippolito April 2009