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Geodynamics Simplified subduction thrust earthquake cycle
The subduction-thrust earthquake cycle can be simplified into two stages:
1. Interseismic period or between earthquakes (100's of years) |
- Plate convergence is on-going but the two plates are locked over
some width of the subduction thrust fault, resulting in both uplift
and horizontal shortening of the overlying plate margin;
- the inland extent of the deformation and the location of the areas
of maximum deformation are determined by the extent and the location
of the locked zone; conversely, the width and location of the locked
or seismogenic zone can thus be constrained from the patterns of surface
deformation.
2. Coseismic period or earthquake rupture (a few minutes) |
- once the accumulating stress exceeds the strength of the fault,
the locked zone fails and a great earthquake occurs;
- during the rupture, stored elastic strain is released resulting
in coseismic subsidence & horizontal extension in those region
where slow uplift & horizontal shortening had accumulated.
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