| A | B |
|---|
| volcano | a vent in earth's surface that often forms a mountain built of lava and volcanic ash, which erupts and builds up |
| vent | in volcanic regions, an opening in Earth's surface through which can flow lava, ash, cinders, smoke, and steam |
| crater | the steep-walled depression at the top of a volcanic vent |
| Pacific Ring of Fire | the area around the Pacific Plate where volcanoes and earthquakes are common due to tectonic movement |
| hot spot | areas in Earth's mantle that are hotter than the neighboring areas, forming melted rock that rises toward the crust |
| geothermal energy | thermal energy from magma bodies inside Earth that can be used to produce electricity with very little environmental pollution |
| hot dry rock (HDR) | a new technology in which heat from Earth's internal hot dry materials is used to generate energy |
| shield volcano | a broad volcano with gently sloping sides, built by eruptions of fluid basaltic lava, which spreads out in flat layers; example: the Hawaiian Islands |
| tephra | lava that is blasted into the air by violent volcanic eruptions and solidifies as it falls to the ground as ash, cinders, and volcanic bombs |
| cinder cone | a type of volcano in which tephra (cinders) piles up into a steep-sided cone |
| composite volcano | a type of volcano built of silica-rich lava and tephra layers accumulated from repeated alternating cycles of tephra eruptions and lava eruptions |
| batholith | the largest intrusive igneous rock bodies that form when magma cools and solidifies underground and stops rising to the surface |
| dike | an intrusive igneous rock body formed when magma is squeezed into a vertical crack that cuts across rock layers and solidifies underground |
| sill | an intrusive igneous rock body formed when magma is squeezed into a horizontal crack between rock layers and solidifies underground |
| volcanic neck | the solid igneous core of a vent that remains after the outer layers of lava and tephra have been eroded away from an extinct volcano |
| caldera | the large opening formed at the top of a volcano when a crater collapses into the vent following eruption |
