EESC1168 Lecture Notes - Lecture 9: Plate Tectonics, Oceanic Crust, Subduction
10 Feb 2017
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A volcano is an opening in earth"s crust that allows warm material to escape to earth"s surface. Volcanoes can be active, dormant, or extinct. Active: a volcano that has recently erupted (i. e. in the last 10,000 years) Dormant: a volcano that has not erupted recently, but is capable of erupting again. Extinct: a volcano that is not expected to erupt again. Often in the center of a plate, but not always. Iceland - hot spot in center of divergent zone, fault lines. Either 2 oceanic plates meet, or an oceanic plate and a continental plate meet. Get the ability to produce volcanic activity. Two plates pulling apart and magma able to escape. Magma (molten, liquid rock) must form inside the earth and make it to earth"s surface. Dissolved gases may also travel with the magma, becoming part of the eruption. This lowers its melting temperature so the rock is able to melt. Now we have magma - liquid rock.
