Volcano

Shiprock, New Mexico a volcanic neck in the distance, with radiating dike on its south side (left).

Click image for larger view

Photo credit: USGS Digital Data Series DDS-21 CD-ROM

Locations of Volcanic Activity

(Map)

• Along subduction zones

• Midoceanic ridge

• Hot spots (mantle plumes)

Type of Volcanoes

Effusive Eruptions

• Fluid lava - low silica content

• Basaltic Lava

• aa & pahoehoe

  • Video:

    • Pahoehoe flow (Warning! 1.5 megabyte QuickTime movie) (from VolcanoWorld)

    • Pahoehoe flow (Warning! 1.8 megabyte Mpeg movie) (from VolcanoWorld)

• Flank Eruptions

• Lava ponds and tubes

• Shield Volcano Example: Mauna Loa, Hawaii

Panorama from Kilauea Caldera (QuickTime VR, Source: M.Ritter) 

Explosive Eruptions

• viscous lava (more silica)

• magma tends to block conduit

• Pyroclastic Flow

Supplemental Web Sites

• Kilauea and Mount St. Helens: How Chemistry Controls Volcanoes

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© Michael Ritter mritter@uwsp.edu
Last revised March 11, 2007