Key Words Flashcards
Asthenosphere
The partially molten of the mantle on which Earths tectonic plate line
Convection
The movement of mantle material in cells when heated by radiation from the earths core
Sea Floor Spreading
The movement of oceanic crust away from a constructive plate boundary, as recorded by the magnetic stripes in basaltic rock
Lithosphere
The rigid, outermost layer of the worth from which tectonic plates are formed. It is made up of the crust and upper mantle.
Slab Pull
At a subduction zone the descending part of the oceanic plate pulls the rest of the plate with it
Subduction
The melting of an oceanic plate as it descends into the mantle at a convergent (destructive) boundary
Benioff Zone
zone where a descending oceanic plate is in contact with a continental plate as it is subducted. It is a zone of earthquake activity
crustal fracturing
Occurs when the earth’s crust causes rock to break and fracture under stress and strain caused by seismic stresses.
Hotspot
An intra-plate location where magma from the mantle has broken through a weak point in the crust.
Intra-plate earthquake
Earthquakes that occur away from the plate boundaries and closer to the middle of a tectonic plate.
Liquefaction
Groundwater and loose soil and sediments are shaken during an earthquake so that the ground loses cohesion and acts like a fluid.
Magnitude
The amount of energy released by a tectonic event
Mantle Plume
Hotter areas of the mantle that move upwards underneath the crust and push it up. They can cause weak spots in the crust that can become hotspots. There are two major mantle plumes - Pacific and African.
Mercalli Scale
An earthquake intensity scale based on 12 levels of damage to areas.
Moment Magnitude Scale
The most accurate earthquake magnitude scale, it measures the total energy released by an earthquake.
