Chapter 25.4 Flashcards
Viscosity
The measure of a fluid’s resistance to flow.
Silica
Chemical compound silicon dioxide, SiO2s
Cinder Cone volcanoes
Smaller, have heights in the hundreds of meters range, and have short eruption cycles.
Shield volcanoes
Broad, flat structures composed of layer upon layer of lava flows.
Composite volcanoes
Large and steep-sided, often thousands of meters high and tens of kilometres across the base and composed of layers of both lava and ash.
Where can melting occur?
In the Asthenosphere.
Why does magma rise?
It is less dense then the surrounding rock.
How does magma rise?
It rises if the pressure condition allows it to and if it flows through the conduits of rocks.
Where and how do volcanic eruptions occur?
They occur where plates separate along a mid oceanic ridge or collide along a subduction zone.
Where are most of earth’s volcanoes located?
They are located around the plate boundaries that surround the pacific ocean called the ring of fire.
What are hot spots?
Hot spots are areas of volcanic activity where magma moves toward the surface in large, balloon like plumes.
Where do hot spots originate?
Scientists hypothesize that these plumes originate near the core-mantle boundary.
What are pryroclastic material?
Solid material shot out from volcanic eruptions.
What is the smallest pyroclastic material?
Ash
What is the biggest pyroclastic material?
Blocks and bombs
