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Three Types of Volcanoes. Shield Volcanoes. Low silica level Low viscosity Lava High or low levels of gas Low to medium explosivity Flattened mound Resembles a warrior’s shield. Mauna Loa, Hawaii. Piton de la Fournaise. Surtsey, Finland. Composite Volcanoes. High in silica
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Shield Volcanoes • Low silica level • Low viscosity Lava • High or low levels of gas • Low to medium explosivity • Flattened mound • Resembles a warrior’s shield
Composite Volcanoes • High in silica • High viscosity magma • High levels of gas • Highly explosive • Cone shaped • Formed by layers of lava and ash
Cindercones • Low silica lava • High levels of gas • “Fire-fountain” eruptions • Commonly found on the flanks of shield volcanoes • Made from a pile of rock pieces • Structurally weak