ERTH 2415 Lecture 6: Lecture06
26 Sep 2015
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Document Summary
Erth 2415 - lecture 6: plate tectonics and earthquakes. The central area sags: rift - valley created at a pull-apart zone, spreading: new ocean floor is formed in pulled-apart area. Ex. of a young spreading center is east african rift system. Failed rifts do not fully develop into new oceans. Stop at stage 3 creating zones of weakness in the crust: convergent zones and earthquakes, convergent zone is a region where two tectonic plates collide. Dominant deformation force is compression: immense amount of energy is released. Farallon plate splits in two: remnants of the farallon plate destroyed by subduction under the north. American plate, subducting at a rate of a few cms per year: cascadia megathrust fault is locked. American plate to bulge up (upward bulge of vancouver island). North american plate will rebound causing a great earthquake and tsunami: seismicity dominated by crustal earthquakes. North american plate: largest risk from crustal earthquakes.
