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| A type of lava flow that has a jagged, blocky surface. |
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| A large mass of igneous rock that formed when magma was emplaced at depth, crystallized, and was subsequently exposed by erosion. |
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Lava having a surface of angular blocks associated with material having andesitic and ryholitic compositions. |
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| A large depression typically caused by collapse of the summit area of a volcano following a violent eruption. |
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| A pattern of cracks that forms during cooling of molten rock to generate columns. |
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| A volcano composed of both lava flows and proclastic material. |
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| A ter used to describe intrusive igneous masses that form parallel to the bedding of the surrounding rock. |
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| A pipelike opening through which magma moves toward Earth's surface. It terminates at a surface opening called a vent. |
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| Mountains formed in part by igneous activity associated with the subduction of oceanic lithosphere beneath a continent. Examples include the Andes and the Cascades. |
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| The depression at the summit of a volcano, or that which is produced by a meteorite impact. |
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| A tabular-shaped intrusive igneous feature that cuts through the surrounding rock. |
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| A term used to describe plutons that cut across existing rock structures, such as bedding planes. |
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| Buoyant plumes of hot ash-laden gases that can extend thousands of meters into the atmosphere. |
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| A crack in rock along which there is a distinct separation. |
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| An eruption in which lava is extruded from narrow fractures or cracks in the crust. |
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| Flows of basaltic lava that issue from numerous cracks or fissures and commonly cover extensive areas to thicknesses of hundreds of meters. |
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| A vent in a volcanic area from which fumes or gases escape. |
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| A proposed concentration of heat in the mantle capable of introducing magma that in turn extrudes onto Earth's surface. the intraplate volcanism that produced the Hawaiian Islands is one example. |
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| Igneous activity that occurs within a tectonic plate away from plate boundaries. |
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| A chain of volcanic islands generally located a few hundred kilometers from a trench where there is active subduction of one oceanic plate beneath another. |
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| A massive, concordant igneous body intruded between preexisting strata. |
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| Mudflows on the slopes of volcanoes that result when unstable layers of ash and debris become saturated and flow downslope, usually following stream channels. |
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| Tunnel in hardened lava that acts as a horizontal conduit for lava flowing from a volcanic vent. Lava tubes allow fluid lavas to advance great distances. |
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| A mass of hotter-than-normal mantle material that ascends toward the surface, where it may lead to igneous activity. These plumes of solid yet mobile material may originate as deep as the core-mantle boundary. |
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| Incandescent volcanic debris that is buoyed up by hot gases and moves downslope in an avalanche fashion. |
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| A lava flow with a smooth-to-ropy surface. |
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| A volcanic cone that forms on the flank of a larger volcano. |
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| Basaltic lava that solidifies in an underwater environment and develops a structure that resembles a pile of pillows. |
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| A vertical conduit through which magmatic materials have passed. |
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| A structure that results from the emplacement and crystallization of magma beneath Earth's surface. |
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| The volcanic rock ejected during an eruption. Pyroclastics include ash, bombs, and blocks. |
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| A highly heated mixture, largely of ash and pumice fragments, traveling down the flanks of a volcano or along the surface of the ground. |
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| A rather small volcano built primarily of pyroclastics ejected from a single vent. |
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| A broad, gently sloping volcano built from fluid basaltic lavas. |
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| A tabular igneous body that was intruded parallel to the layering of preexisting rock. |
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| Stratovolcano/Composite Cone |
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| A volcano composed of both lava flows and proclastic material. |
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| Describinh a feature such as an igneous pluton having two dimensions that are much longer than the third. |
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| Circular conduit or pipe that terminates at a surface opening. |
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| A measure of a fluid's resistance to flow. |
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| A chain of volcanic islands generally located a few hundred kilometers from a trench where there is active subduction of one oceanic plate beneath another. |
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| An isolated, steep-sided, erosional remnant consisting of lava that once occupied the vent of a volcano. |
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| A mountain formed from lava and/or pyroclastics. |
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| Gaseous components of magma dissolved in the melt. Volatiles will readily vaporize at surface pressures. |
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