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 VOLCANO
VOCABULARY |
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Photo Glossary of Volcanic Terms from USGS. http://volcanoes.usgs.gov/Products/Pglossary/pglossary.html This is a good
index
of terms about volcanoes. Volcanic and Geologic Terms from Volcano World. http://volcano.und.nodak.edu/vwdocs/glossary.html |
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| 'A'a |
lava flows that have a rough rubbly surface. Photo |
| active volcano | a volcano that is erupting, or a volcano that is not presently erupting, but that has erupted within historical time and is considered likely to do so in the future. |
| ash | fine particles of pulverized rock blown from an explosion vent. Photo |
| basalt | volcanic rock (or lava) that is dark in color, contains 45% to 54% silica, iron and magnesium. Photo |
| caldera | a basin-shaped depression at least a mile in diameter in a volcano. Crater Lake is a caldera that is in the Oregon Cascades. Photo |
| cinder cones |
a volcanic cone built entirely of loose material. Photo |
| crater | a depression formed by either explosion or collapse at a volcanic vent. It usually has steep sides. |
| dormant volcano | a volcano which is presently inactive but which may erupt again. Most of the major Cascade volcanoes are believed to be dormant rather than extinct. |
| eruption |
the process by which solid, liquid, and gaseous materials are ejected into the earth's atmosphere and onto the earth's surface by volcanic activity. Eruptions can be a quiet overflow of liquid rock or a tremendously violent explosion. |
| extinct volcano | a volcano that is not presently erupting and is not likely to do so in the future. |
| fissures | fractures or cracks on the slopes of a volcano. Photo |
| geyser |
hot springs that rise along cracks and erupt on the earth's surface. Surface water percolates downward through the rocks below the Earth's surface to high-temperature area. Geysers are found in regions of young volcanic activity. Old Faithful Web Cam |
| lava | melted (molten) rock which has reached the surface of the earth through a volcanic eruption. Cooled and solidified rock is also called lava. Photo |
| lava flow | the outpouring of lava onto the land from a vent or fissure. Photo |
| lava tube | a tunnel formed when the surface of a lava flow cools and solidifies while the still-molten interior flows through and drains away. Photo |
| magma | melted (molten) rock inside the earth |
| pahoeho | Hawaiian term for lava with a smooth, billowy, or ropy surface. Photo |
| pillow lava |
the formation of basalts that erupt underwater Photo |
| plate | 10 fragments of the earth's crust which move in relation to one another. |
| Ring of Fire | the regions of mountain-building earthquakes and volcanoes which surround the Pacific Ocean. Diagram |
| Volcanologist | a person who studies volcanoes and their behavior |
| Volcanology | the science of volcanoes |
| Vulcan | Roman god of fire and the forge after whom volcanoes are named. |