GPS Measures Deformation in Subduction Zone: Island Arc Setting

48s Novice

Optional Files 1

How does land jump in an earthquake?

This animation shows that 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. This animation is exaggerated to depict the relative motion of plates and GPS as seen in the 2011 Magnitude 9 earthquake in Japan.

Keypoints:

  • Modern GPS measures incremental movement of earth's surface
  • Worldwide monitoring of the overriding plate in subduction zones shows the coastline is pushed relentless back until friction is overcome. 

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GPS Records Variable Deformation across a Subduction Zone

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  3. no movement far inland above the deeper part of the diving oceanic plate.
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