Earth Sciences 2240F/G Lecture Notes - Lecture 7: Megathrust Earthquake, Continental Shelf, Interplate Earthquake
8 Oct 2020
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Thrust fault: one rock block thrust up over by compressive stress. Megathrust fault: same relative action (one block moving up) but consider whole boundary. *during time plates are stuck, stress is accumulating, rocks in vicinity of thrust zone are deformed. When stress accumulated in front end of deformed plate sufficient to break stuck plate, sudden release of energy produce megathrust earthquake. Definition of megathrust earthquake: occur at interplate zone where 1 plate subducts beneath another, occur upon sudden release of previously locked section, magnitude greater than 7. 0 and commonly in range of 9. 0. Not the first of its kind in that regions and waiting for the next. Plate tectonics: west coast of north american has every type of plate tectonics therefore every type of earthquake too. Event: earthquake was single event, rupture broke whole lenth of cascadia subduction zone, when coastal lands sink below sea level, trees can"t survive in salt water.
