Types of Volcanoes
- Created by: georgia_casey
- Created on: 13-11-18 22:52
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- FISSURE
- VOLCANO TYPES
- SHIELD
- C PM or HSPs
- basaltic rock
- form gently sloping cones, less viscous lava
- gentle & unpredictable
- Mauna Loa, Hawaii
- basaltic
- COMPOSITE
- most common found on land
- D PM
- layers of ash - initial explosive phases & subsequent lava layers main eruption
- rhyolitic lava
- thick, viscous
- magma cools in main vent
- plugs and traps
- gas released through secondary vent
- sudden and violent release
- Mt Etna & Vesuvius
- explosive & unpredictable
- ACID / DOME
- continental crust
- steep sided
- formed from viscous lava
- can't travel far, convex volcanoes
- formed from viscous lava
- lava may solidify in vent
- revealed later by erosion
- Puy de Domes, France
- explosive & unpredictable
- Rhyolitic
- CALDERA
- D PM
- form from built up gases
- blocked vent - catastrophic eruption, destroy summit
- enormous crater
- sometimes fills with water
- enormous crater
- blocked vent - catastrophic eruption, destroy summit
- eruptions = explosive and unpredictable
- Krakatoa, Indonesia
- andesitic
- lower temp
- more silica, viscous, doesn't travel far
- dissolved gas
- likely to explode
- high eruptions spread gases
- may cause collapse of column
- high eruptions spread gases
- likely to explode
- SHIELD
- elongated crack in crust, lava spill over large area
- 2010, Eyjafjallajokull
- C PM
- typically @ spreading ridges (MA)
- basaltic lava
- gentle & persistent
- basaltic
- hot
- low viscosity
- easy release of gases
- non-violent eruptions
- runny lava
- low cones = low gas plumes
- lava spreads far, cools quickly
- cones = low and wide based
- VOLCANO TYPES
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