1
fragments of pulverized rock, minerals and volcanic glass, created during volcanic eruptions, less than 2 mm (0.079 inches) in diameter
2
Clastic rocks composed solely or primarily of volcanic materials
3
Circular depression in the ground caused by volcanic activity.
4
mixture of molten or semi-molten rock, volatiles and solids that is found beneath the surface of the Earth
5
Molten rock on the surface
