Ash Cloud: Volcanic ash that has fallen through the air from an eruption cloud. A deposit so formed is usually well sorted and layered.


Crater :A steep-sided, usually circular depression formed by either explosion or collapse at a volcanic vent.


Summit: The highest point of the volcano.

Conduit:a channel or tube through which the magma rises

Base: The bottom of the volcano

Vent: Hole in the volcano through which the pressure of gases and lava are released

Parasitic Cone: a alternate channel through which magma rises that is not connected to the volcanic summit

Throat: the widening of the conduit near the summit of the volcano

Magma Resevoir: the place where magma, gases, and other volcanic materials are kept before they erupt under pressure.

Sill: A tabular body of intrusive igneous rock, parallel to the layering of the rocks into which it intrudes.


Lava: lava is made of elements of silicon, oxygen, aluminum, iron, magnesium, calcium, sodium, potassium, phosphorus, and titanium (plus other elements in very small concentrations.


Flank: An eruption from the side of a volcano (in contrast to a summit eruption.)


Ash: Fine particles of pulverized rock blown from an explosion vent. Measuring less than 1/10 inch in diameter, ash may be either solid or molten when first erupted. By far the most common variety is vitric ash (glassy particles formed by gas bubbles bursting through liquid magma).


Base: The bottom of the volcano.