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| the region below the lithosphere, variously estimated as being from fifty to several hundred miles (eighty-five to several hundred kilometers) thick, in which the rock is less rigid than that above and below but rigid enough to transmit transverse seismic waves. |
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| Body waves are waves that travel through the Earth or other elastic body, for example as the result of an earthquake, explosion, or some other process that imparts forces to the body. |
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| Continental cratons have deep roots that extend down into the mantle. |
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| convection currents[image] |
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Definition
Convection within earth's mantle is the driving force for plate tectonics. |
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| Deep-focus earthquake[image] |
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Definition
| A deep-focus earthquake is an earthquake that occurs at depths between 300 and 700 km beneath the Earth's surface. |
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| An earthquake (also known as a tremor or temblor) is the result of a sudden release of energy in the Earth's crust that creates seismic waves. |
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| The epicenter or epicentre is the point on the Earth's surface that is directly above the hypocenter or focus, the point where an earthquake or underground explosion originates. |
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| a fault, or fault line, is a planar fracture in rock in which the rock on one side of the fracture has moved with respect to the rock on the other side. |
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| The location of an earthquake's hypocenter is the position where the energy stored in the strain in the rock is released, which occurs at the focal depth below the epicentre. |
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| a hotspot is a location on the Earth's surface that has experienced active volcanism for a long period of time. |
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| the lithosphere includes the crust and the uppermost mantle which is joined to the crust across the mantle. |
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| Mantle convection is the slow creeping motion of Earth's rocky mantle in response to perpetual gravitationally unstable variations in its density. |
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Pangaea, Pangæa or Pangea, from παν, pan, meaning entire, and , Gaea, meaning Earth in Ancient Greek) was the supercontinent that existed during the Paleozoic and Mesozoic eras about 250 million years ago, before the component continents were separated into their current configuration. |
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| P-waves are type of elastic wave, also called seismic waves, that can travel through gasses (such as sounds), elastic solids and liquids, including the Earth. |
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| Ridge-push is a proposed mechanism for plate motion in plate tectonics . |
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A type of seismic wave, the S-wave, secondary wave, or shear wave (sometimes called an elastic S-wave) is one of the two main types of elastic body waves, so named because they move through the body of an object, unlike surface waves. |
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Term
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Definition
| Seismic waves are waves that travel through the Earth or other elastic body, for example as the result of an earthquake, explosion, or some other process that imparts forces to the body. |
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Term
shallow-focus earthquake[image] |
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Definition
| The majority of tectonic earthquakes originate at the ring of fire in depths not exceeding tens of kilometers. Earthquakes occurring at a depth of less than 70 km are classified as 'shallow-focus' earthquakes. |
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| There are two accepted models for VPM formation: hotspots /mantle plumes and slab pull . |
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| In physics, a surface wave is a mechanical wave that propagates along the interface between differing media, usually two fluids with different densities. A surface wave can also be an electromagnetic wave guided by a refractive index gradient. |
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| A terrane in geology is a fragment of crustal material formed on, or broken off from, one tectonic plate and accreted — "sutured" — to crust lying on another plate. |
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| thin-skinned thrusting[image] |
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Definition
| Rock beds are folded in chevron folds. They are cut by thin skinned thrusts. |
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| A volcanic belt is a large volcanically active region. Other terms are used for smaller areas of activity, such as volcanic fields. |
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volcanic island arc[image] |
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Definition
| A volcanic arc is a chain of volcanic islands or mountains formed by plate tectonics as an oceanic tectonic plate subducts under another tectonic plate and produces magma. |
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| A volcano is an opening, or rupture, in a planet's surface or crust, which allows hot, molten rock, ash, and gases to escape from below the surface. |
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