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Ch.12
vocabulary
Term | Definition |
---|---|
Core | the dense center of the earth made of solid and molten iron and nickel |
Mantle | the layer of the earth that surrounds the core; made of both molten magma and solid rock |
Crust | the thin, solid, rocky outermost layer of the earth |
Differentiation | the process of Earth materials separating and sorting by density resulting in a layered structure with the densest material (FE & NI) settling in the core |
Tectonic Plate | a large section of the earth’s crust that moves and carries everything on it |
Hotspot | a stationary, high temperature area of melting within the earth mantle that can last for several millions of years where superheated mantle magma rises towards the surface. |
Rift valley | A long, narrow rip or opening, made by the stretching pulling or splitting apart of the earth’s crust through which mantle magma reaches the surface adding new crust to the edge of a tectonic plates |
Seafloor spreading | the theory that oceans widen (open up) and continents are pushed apart as new crust is formed at mid ocean ridges |
Plate tectonic | the theory that the earth’s surface is made of large sections of crust that move and interactive with each other |
Continental drift | the theory that the major landmasses of the earth were once part of one large single super continent that broke apart 200 million years ago |
Mid Ocean Ridge | a long underwater mountain range that is split by a rift valley where mantle magma rises and forms new oceanic crust |
Convection current | the circular flow of magma within the molten part of the mantle as it heads up and cools down |
Seismic wave | a type of vibrating or shaking activity produced by the movement of earth's tectonic plates |
Paleomagnetism | a record of the earth’s magnetic field preserved by the alignment minerals in the rock of the earth’s crust time that the rocks were formed at the mid ocean ridge |
Focus | the point inside the earth where rock first moves starting an earthquake |
Epicenter | the point on the earth’s surface directly over the focus of an earthquake |
Richter scale | the scale used to measure the magnitude or strength of an earthquake |
Deformation | the process of physically changing the earth’s crust as a result of tectonic forces |
Viscosity | the ability of a substance to resist flowing |
Fault | a break or fracture in the earth’s crust caused by tectonic forces |
Seismologist | a scientist that studies the behaviors and characteristics of earthquake |
Lag time | the amount of time that passes between the arrival of the first P wave and the first S wave |
Magnitude | a measure of the amount of energy released during an earthquake |
Continental Margin | the edges of the continents below sea level that represent the shallowest parts of the oceans |
Plate boundary | an area on the earth’s surface where the edges of tectonic plates are interacting |
Subduction | the geologic process by which one tectonic plate is forced downward into the mantle under another tectonic plate |
Ring of Fire | an area of high subduction activity and frequent volcanic eruptions surrounding the pacific plate |
Geothermal Energy | a renewable energy source that originates from the earth’s own internal heat |
Tectonic Forces | forces generated from within the earth that result in uplift movement or deformation of the earth’s crust |
Volcanic arc | an arcing chain volcanic islands or volcanic mountains formed by a subduction of an oceanic plate into the mantle under another tectonic plate |