This preview has intentionally blurred sections. Sign up to view the full version.View Full Document
Unformatted text preview: o add water (later, water makes it explosive) ← ← Volcanic rocks ← Dark Intermediate Light ←- basalt - andesite - rhyolite ←- low silica - int. silica - high silica ←- low viscosity - int. viscosity - high viscosity ←- low in gas - can be high in gas ←- mostly lava flow - mostly ash ← ← silica-SiO2 ← viscosity-stickiness/ease of flow ←-to get an explosive eruption need high viscosity and gas (H2O vapor) • high viscosity and no gas = no explosive eruption • low viscosity with gas = no explosive eruption • low viscosity and no gas = no explosive eruption ← ←- most explosive volcanoes are located at subduction zones (because their magma has water vapor in it, and tend to have a higher viscosity)...
View Full Document
- Spring '08
- Volcanology, Volcano, explosive eruption, rock lava- magma