Subduction Zone: Simplified model of elastic rebound

What is elastic rebound in subduction zones?

Oblique view of a highly generalized animation of a subduction zone where an oceanic plate is subducting beneath a continental plate. (See sketch below for parts.) This scenario can happen repeatedly on a 100-500 year cycle. The process which produces a mega-thrust earthquake would generate a tsunami, not depicted here.


Keypoints:

During subduction:

  • the heavier, thinner plate dives beneath the more-buoyant plate
  • Two tectonic plates are locked at the contact by immense friction.
  • The overlying plate is forced backward creating strain
  • When friction is overcome the plate rebounds along the contact to a more-relaxed position 

Total Time: 25s
Level: Novice

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GPS can record the movement of the leading edge of the overlying continental plate in a subduction zone. The plates are locked and the overlying plate is forced back. When friction is overcome and strain is released, the GPS receiver will snap back toward its original position. 

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