Earth Sciences 2240F/G Study Guide - Types Of Volcanic Eruptions, United States Coast Guard, 2004 Indian Ocean Earthquake And Tsunami

• School: Western University
• Department: Earth Sciences
• Course: Earth Sciences 2240F/G
• Professor: Kristy F Tiampo

Document Summary

During the lifetime of a subduction zone (where two plates meet), compressive activity is always happening. The plates do not continually slide against each other, but build up friction at contact points over the course of time. During this time massive amounts of stress accumulate, causing the rocks in the vicinity to deform while locking against one another. When the point is reached that the accumulated stress of the deformed plate is sufficient to cause the lock to break, the sudden release of energy produces a megathrust earthquake. All of the world s largest earthquakes are megathrust earthquakes accounting for the release of 90% of the earth s seismic energy. Megathrust earthquakes: occur at an interplate zone where one plate subducts beneath another, occur upon the sudden release of a previously locked section, has a magnitude greater than 7. 0 and commonly in the range of 9. 0.