GEOG 1125 Lecture Notes - Lecture 4: Lithification, Mafic, Induced Seismicity
3 Nov 2016
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Document Summary
Asthenosphere: not rigid, consists of unevenly heated molten rock. Lithosphere: is rigid; consists of the upper crust and the mantle. Plate boundaries: 3 types are convergent, divergent, and transform: convergent: 2 plates colliding, one of which is generally oceanic. Subduction zone: where one plate goes under the other (usually oceanic under continental because oceanic plates have thinner crusts) Volcanic arcs: magma is given a path to the surface; ex. Associated hazards include volcanoes, megathrust earthquakes, and tsunamis: divergent: 2 plates separating or rifting in oceans. Sea floor spreading: magma from the mantle fills the gap between 2 plates, forming a new crust: transform: 2 plates sliding past each other; ex. Associated with earthquakes - friction along plate boundaries. Volcanoes: places where magma can make its way to earth"s crust; occur in 3 areas which are subduction zones, sea-floor spreading zones, and hotspots. Active volcanoes are those which have erupted in recent history.
