GEO 110 Lecture Notes - Lecture 4: Emergency Management, Mercalli Intensity Scale, Seismic Wave
31 Oct 2016
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Document Summary
Made up certain minerals: basalt and gabbro. Denser, cooler and has a low viscosity (flows a considerable distance) Made up of sial: silica and aluminum. Before the continents broke away from one another. Continents were separated by the sea of proto-tethys. Magma convection: when materials are hot, they become light and buoyant, very hot magma will always rise to the surface, when the rocks cool down, they contract (fall apart) Sea floor spreading: when two oceanic plates collide and cracks/fissures develop between them, magma spreads out and solidifies to form either an island or a submerged rock. Theory that the lithosphere is divided into a number of plates that float independently over the mantle and along whose boundaries occur the formation of the new crust, the building of mountains ad activity that causes earthquakes. Plate boundaries fall into three categories: zones where two plates diverge, zones where two plates converge, zones where plates slide pass one another (transform plate boundaries.
