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PVMS Tectonic Plates
Term | Definition |
---|---|
Asthenosphere | The layer of the Earth that lies below the lithosphere. It is made of the lower mantle and core of the Earth. |
Convection | The process by which heat from the Earth’s core is transferred upwards to the surface. |
Core | Innermost layers of Earth. |
Crust | The outermost layer of Earth's layers. |
Lithosphere | The solid, outer part of the Earth that includes the upper mantle and crust. |
Mantle | Layer of the Earth that is below the crust |
Plate Tectonics | The theory that pieces of Earth's lithosphere are in constant motion, driven by convection current in the mantle. |
Plate | A section of the lithosphere that slowly moves over the asthenosphere, carrying pieces of continental and oceanic crust. |
Convergent boundary | A boundary where two tectonic plates are coming together. |
Divergent boundary | A boundary where two tectonic plates are moving apart. |
Mid-Oceanic Ridge | Type of divergent plate boundary in the middle of an ocean where new oceanic crust is forming at the center. |
Subduction Zone | Type of convergent plate boundary where oceanic crust is subducting under another crustal plate due to density differences. |
Transform boundary | A boundary where two tectonic plates are sliding past one another. |
Alfred Wegner | German scientist who developed the theory of Continental Drift. |
Continent | A division of Earth’s seven main divisions of land. |
Continental Drift | The idea that the continents were once all together and have drifted apart since. |
Crustal Plate | Massive hard brittle chucks of the Earth's crust that can be either oceanic or continental |
Pangaea | Supercontinent made of all the continents prior to their break up. |
Earthquake | A natural shaking of lithosphere when rocks are displaced due to a sudden release of energy. |
Epicenter | Point on Earth's surface directly above the focus of an earthquake. |
Fault | A crack among rock layers caused by an earthquake where 2 tectonic plates have moved. |
Focus | Point of the initial fault rupture where an earthquake originates that usually lies at least several kilometers beneath the Earth's surface. |
Normal fault | A type of fault caused by tension in the crust, where one plate slides down compared to the other. |
Primary wave (p wave) | The fastest seismic wave; the seismic wave that squeezes and pulls rocks in the same direction that the wave travels |
Reverse fault | A type of fault caused by compression in the crust where one plate is thrusted over the other. |
Secondary wave (s wave) | The wave that travels half as fast as the primary wave; the seismic wave that causes rock particles to move at right angles to the direction of the wave. |
Seismic wave | A wave of energy that is generated by an earthquake or other earth vibration and that travels within the earth or along its surface. |
Seismograph | An instrument used to detect and record seismic or earthquake waves |
Surface wave (l wave) | The slowest seismic wave; seismic wave that moves in two directions as it passes through rocks, causing the ground to move both up and down and from side to side, and is the most destructive wave. |
Transform fault | A type of fault where rocks on either side move past each other sideways with little up or down motion. |