FDSCI 201 Exam 2
Volcanoes Questions &
Answers
Shield - ANSWERSSides are not steep, expansive, erupts basalts (low viscosity).
Stratovolcano (Composite) - ANSWERSSteep sides, high elevation, near subduction zones,
erupts basalt/andesite/rhyolite.
Caldera - ANSWERSCan be very large, collapsed roof of a composite volcano, most explosive,
erupts rhyolite (high viscosity).
Other types of Volcanoes - ANSWERSFissure, Cinder Cone, Tuff Cone, Volcanic Dome, Hot
Springs, Geysers, Fumaroles.
Fissure - ANSWERSLong cracks in surface of the earth that spew lava. Seal up and lead to
fumaroles of cinder cones.
Cinder Cones - ANSWERSOnly erupt once, uncosolidated material.
Tuff Cone - ANSWERSVery explosive because they erupt through water saturated materials. Only
erupt once.
Lava Dome - ANSWERSVery viscous lava, very slow. Usually located in the crater of a previously
erupted volcano. Can cause pyroclastic flows.
Hot Spring - ANSWERSWater at surface
, Geysers - ANSWERSWater close to surface
Fumarole - ANSWERSWater far below surface
Volatile - ANSWERSGases. At higher pressures they dissolve into magma. Expansion caused by
increase in temperature, decrease in pressure. Escape can cause volcanic eruption. Higher gas
content, harder to espace = more explosive.
Volcano Origins - ANSWERSMid-ocean Ridges. Subduction Zones. Hot Spots.
Mid-Ocean Ridges - ANSWERSProduces 75% of the earth's lava. Low viscosity basalt. Produces
shield volcanoes.
Subduction Zones - ANSWERSComposite volcanoes. Andesite lava, intermediate viscosity. More
than 80% or eruptions in historic times come from subduction zone volcanoes. Ring of Fire.
Unpredictable.
Hot Spots, Oceans - ANSWERSShield volcanoes, basalt.
Hot Spots, Continents - ANSWERSCalderas, ryholite.
Rhyolite - ANSWERSLight colored, high silica content, often tuff (explosively erupts), often
containts pumice. Extrosive.
Andesite - ANSWERSIntermediate colors, intermediate silica content, can erupt explosively.
Extrusive.
Volcanoes Questions &
Answers
Shield - ANSWERSSides are not steep, expansive, erupts basalts (low viscosity).
Stratovolcano (Composite) - ANSWERSSteep sides, high elevation, near subduction zones,
erupts basalt/andesite/rhyolite.
Caldera - ANSWERSCan be very large, collapsed roof of a composite volcano, most explosive,
erupts rhyolite (high viscosity).
Other types of Volcanoes - ANSWERSFissure, Cinder Cone, Tuff Cone, Volcanic Dome, Hot
Springs, Geysers, Fumaroles.
Fissure - ANSWERSLong cracks in surface of the earth that spew lava. Seal up and lead to
fumaroles of cinder cones.
Cinder Cones - ANSWERSOnly erupt once, uncosolidated material.
Tuff Cone - ANSWERSVery explosive because they erupt through water saturated materials. Only
erupt once.
Lava Dome - ANSWERSVery viscous lava, very slow. Usually located in the crater of a previously
erupted volcano. Can cause pyroclastic flows.
Hot Spring - ANSWERSWater at surface
, Geysers - ANSWERSWater close to surface
Fumarole - ANSWERSWater far below surface
Volatile - ANSWERSGases. At higher pressures they dissolve into magma. Expansion caused by
increase in temperature, decrease in pressure. Escape can cause volcanic eruption. Higher gas
content, harder to espace = more explosive.
Volcano Origins - ANSWERSMid-ocean Ridges. Subduction Zones. Hot Spots.
Mid-Ocean Ridges - ANSWERSProduces 75% of the earth's lava. Low viscosity basalt. Produces
shield volcanoes.
Subduction Zones - ANSWERSComposite volcanoes. Andesite lava, intermediate viscosity. More
than 80% or eruptions in historic times come from subduction zone volcanoes. Ring of Fire.
Unpredictable.
Hot Spots, Oceans - ANSWERSShield volcanoes, basalt.
Hot Spots, Continents - ANSWERSCalderas, ryholite.
Rhyolite - ANSWERSLight colored, high silica content, often tuff (explosively erupts), often
containts pumice. Extrosive.
Andesite - ANSWERSIntermediate colors, intermediate silica content, can erupt explosively.
Extrusive.
