Types of Lava and

What’s the Difference? Magma is composed of molten rock and is stored in the Earth's crust. Lava is magma that reaches the surface of our planet through a volcano vent.

Qualities of Basaltic and Andesitic lava/magma and volcanoes

Silica Rich Magma 2 types, based on silica content: Rhyolite: Greater than 68% silica. Andisite: 52%-63% silica Features of Silica rich volcanoes and lavas include: High viscosity (thick) “Low” temperatures Explosive eruptions Flying rocks and debris (pyroclasts) Possible pyroclastic flows Found at subduction zones Infrequent eruptions Volcanoes are made of alternating layers of ash and lava

Pyroclastic flows: high-density mixtures of hot, dry rock fragments and hot gases that move away from the vent that erupted them at high speeds. They may result from the explosive eruption of molten or solid rock fragments or both. (aka a wave of super hot rock and ash traveling at over 160km/hour)

Pyroclasts

Silica Poor Magma Pretty much only 1 type. Basaltic: Less than 45%-55% silica Features of basaltic volcanoes and lavas include: “hot” temperatures and slow cooling Low viscosity (runny) Usually dark in colour Calm and frequent eruptions.

Caldara A great central depression A volcanic explosion so violent that it destroys the central portion of the volcano

Subduction Zones Heavy and dense basaltic oceanic plate Lighter and less dense continental plate