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Volcano Term Definitions
The undifferentiated rocks that underlie the rocks of interest in an area.
The unstable, newly-formed front of a lava delta.
A swelling of the crust of a lava flow formed by the puffing-up of gas or vapor beneath the flow. Blisters are about 1 meter in diameter and hollow.
Angular chunk of solid rock ejected during an eruption.
Fragment of molten or semi-molten rock, 2 1/2 inches to many feet in diameter, which is blown out during an eruption. Because of their plastic condition, bombs are often modified in shape during their flight or upon impact.