Volcano Notes. Anatomy of a volcano. tephra. vent/crater. lava. pipe. l ayers of volcanic material. magma chamber. 3 Types Volcanic Materials. Magma - hot - melted rock (molten) - beneath the Earth’s surface. 2 . Lava - hot - molten rock
layers of volcanic material
- melted rock (molten)
- beneath the Earth’s surface
- molten rock
- flowing on Earth’s surface
- turns solid as it falls back to the
ash, cinders, and volcanic bombs
1. Amount of trapped gases and water vapor
Composition and viscosity of magma
The elements and minerals that make up the melted rock determine how explosive an eruption will be.
High amounts of silica increase the viscosity of the magma.
Basaltic magma is relatively liquid (low viscosity ; low silica content) when melted and is not usually explosive
Rhyolitic magma is very thick (high viscosity ; high silica content) when molten, and therefore very explosive
3. Temperature of the magma (affects viscosity and explosiveness)