Types of Volcanoes and their Composition
Volcanoes are classified based on Shape of volcano, style of Eruption, & lava Composition. Understanding these important for Geography (Gs1), and also for Disaster Management (Gs3).
Summary Table
Volcano type | Lava type | Silica content | Viscosity | Eruption style | Example |
Shield | Basaltic | Low | Low | Gentle | Mauna lao (Hawaii) |
Composite | Andesitic | Intermediate | Medium | Explosive | Mount Fuji (Japan) |
Cinder cone | Basaltic/Andesitic | Low medium | Medium | Explosive | Paricutin(Mexico) |
Lava Dome | Rhyolitic | High | High | Explosive | Mount st. Helens(USA) |
Caldera | Rhyolitic | High | High | Catastrophic | Yellowstone (USA) |
Type1: Shield Volcanoes these are largest volcanoes in area
Shape: Broad , gently sloping domes (like a shield on mountain)
Lava composition: Andesitic lava. Eruption style: Non-Explosive, fluid lava flows. Examples: Hawaii (Mount
Type2: Composite Volcanoes/ Stratovolcanoes
Shape: Steep-sided, cone-shaped
Lava composition: Andesitic lava
Eruption style: Explosive with ash, Pyroclastic flows, lava
Example: Mount Fuji (Japan)
Type3: Cinder Cone Volcanoes
Shape: Small, steep cone made of pyroclastic fragments
Lava composition:Basaltic to andesitic
Eruption style: Explosive; produces ash and cinders
Example: Parlcutin (Mexico)
These are smallest and most common volcanoes
Type4: Lava Domes/Volcanic Domes
Shape: Dome-like, steep-sided
Lava composition: Rhyolitic lava (High silica, highly viscous)
Eruption style: Slow extrusion of lava : may collapse violently
Example: Mount st. Helens lava Dome
Violent eruptions due to high viscosity
Type5: Caldera Volcanoes
Shape: large, sunken crater
Formation: Collapse of volcano after a major eruption
Lava composition: Usually Rhyolitic
Example: Toba caldera ( Indonesia)
Short and crisp
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