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Earth Science Gr7
Chapter 9
| Term | Definition |
|---|---|
| earthquake | vibrations caused by the rupture and sudden movement of rocks along a break or a crack in the Earth's crust |
| fault | a crack or fracture in the earth's lithosphere along which movement occurs |
| seismic wave | energy that travels as vibrations on and in Earth |
| focus | a location inside Earth where seismic waves originate in rocks first move along a fault and from which seismic waves originate |
| epicenter | the location on Earth's surface directly above an earthquake's focus |
| primary wave | a type of seismic wave which causes particles in the ground to move in a push-pull motion similar to a coiled spring; also called P-waves |
| secondary wave | a type of seismic wave which causes particles to move at right angles relative to the direction the wave travels; also called S-waves |
| surface wave | a type of seismic wave that causes particles in the ground to move up and down in a rolling motion |
| seismologist | scientist that studies earthquakes |
| seismometer | an instrument that measures and records ground motion and can be used to determine the distance seismic waves travel |
| seismogram | a graphical illustration of seismic waves |
| volcano | a vent in the Earth's crust through which molten rocks flows |
| magma | molten rock stored under Earth's surface |
| lava | magma that erupts onto Earth's surface |
| hot spot | a location where volcanoes form far from plate boundaries |
| shield volcano | a large volcano with gentle slopes, basaltic lava, and common along divergent plate boundaries in oceanic hot spots |
| composite volcano | a large, steep-sided volcano that results from explosive eruptions of andesitic and rhyolitic lavas along convergent plate boundaries |
| cinder cone | a small, steep-sided volcano that erupts gas-rich basaltic lava |
| volcanic ash | tiny particles of pulverized rock and glass |
| viscosity | a measurement of a liquid resistance to flow |
| andesitic lava | a viscous, silica-rich lava that flows slowly and forms blocky flows and domes, rather than fluid ropy textures. It's an intermediate type of lava, less fluid than basalt but more so than rhyolite. |
| rhyolitic lava | a very thick and sticky (high-viscosity) lava with a high silica content, resulting in slow-moving, short lava flows, and dangerous explosive eruptions and volcanic domes |
Created by:
carriel
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