Volcano Mid-Ocean Flood Basalt Shield Cinder Cone Stratovolcano Lava Dome Caldera Review Table Ridge small, steep-sided low, broad mountain small mountain, large, steep-sided large depressions extensive plateaus o rift valley o mountain, Landform with slopes <5 , 20-30 slopes, mountain, 10's of km wide up to 9,000-m high up to 400-m high up to 3,000-m high up to ~500-m high Eruption huge volumes of lava lava >> tephra pillow lava tephra >> lava tephra + lava lava > tephra tephra >> lava Products (105 to 106 km3) Magma mafic mafic mafic felsic felsic Composition mafic intermediate Magma low low low low moderate high high Viscosity % Gas in Magma low low low moderate low to high low to high low to high Eruption high discharge rate point source & fissure small eruption column, large eruption column, dome collapse, multiple fissure-fed submarine flows from multiple fissures "fire" fountains fire fountain pyroclastic flows pyroclastic flows pyroclastic flows Style (Hawaiian) (Strombolian) (Plinian) (Pelean) (ultra-Plinian) Explosivity low low low low-moderate very high high ultra-high hydrous (wet) Magma mantle mantle mantle mantle crust/mantle crustal melting crustal melting partial melting partial melting partial melting partial melting Origin melting Plate Tectonic "hot spot" Oceanic Convergent margin numerous numerous numerous numerous Setting (mantle plume) divergent margin (subduction zone) Columbia River, Mid-Atlantic Ridge, Paricutin, Mt. St. Helens, Mt. Unzen, Valles, Long Valley, Mauna Loa, Kilaeua, Examples Deccan Traps, East Pacific Rise, Cerro Negro, Popocatapetl, Mont Pelee, Yellowstone, Joes Hill Siberian Traps Mid-Indian Ridge Sunset Crater San Francisco Peaks Sugarloaf Mtn Superstition Mtns blast, ash fall, blast, ash fall, no significant blast, ash fall, blast, Hazards lava flows lava flows pyroclastic flows, pyroclastic flows, hazards lava flows pyroclastic flows mud flows, landslides tsunami eruptions never some of the largest >70,000 km of form volcanic arcs commonly associated usually monogenetic eruptions rarely observed; role in single mountains mid-ocean ridges around the with stratovolcanoes Comments (erupt once and done) observed mass extinctions(?) on Earth (MORs) on Earth "Ring of Fire" and calderas.