Download Volcano Vocabulary

Volcano Vocabulary
1. ash fall- the ejection of volcanic materials into the atmosphere and the
settling of these materials over a wide area of the surface of the earth
2. caldera- a large, steep-sided, circular or oval volcanic depression that
forms when magma retreats or erupts from a shallow underground
magma chamber; with no magma to support the ground above it, the
overlying rock collapses and the caldera is formed
3. cinder cone- a small (less than 400 meters high) cone-shaped volcano
made of broken rocks or blobs of hardened lava, called “cinders, “ that
accumulate around the volcanic vent
4. composite volcano- a volcano that forms from alternating eruptions of
viscous lava and broken rock. It is steep near the summit and flat
toward the base.
5. lahar- mudflow that occurs when rain falls through clouds of ash or
when rivers become choked with falling volcanic debris
6. lava dome- a bulbous, steep sided dome that forms at the top of a
volcano when thick, relatively “cold” magma emerges from the
volcanic opening
7. lava flow- lava that flows quickly over the surface of the earth and
covers a wide area
8. mudflow- a powerful “river” of mud that forms when debris, such as
from a volcanic eruption, moves into a stream or river
9. pillow lava- balloon like mounds that form when lava erupts under
water or empties into the ocean
10.shield volcano- a wide, broadly sloping volcano that forms from
runny lava. It is the largest of volcanoes
11.volcano- a landform, usually cone shaped, produced by a collection of
erupted material around a vent, or opening, in the surface of the earth
and through which gas and erupted materials pass
12.volcanologist- a scientist who studies volcanoes and volcanic
phenomena
13.rock cycle- the process by which earth materials transform from one
rock type into another
14.igneous rock- a solid earth material that forms when magma or lava
cools and crystallizes on or below the earth’s surface
15.metamorphic rock- a solid earth material that forms when any rock
type is changed by the earth’s high temperature and pressure
16.sedimentary rock- a solid earth material composed of compacted and
cemented sediments or particles of various sizes