Deformation and faulting of subduction overriding plate caused by a subducted seamount
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We conducted numerical experiments to simulate elastoplastic deformation of the overriding plate caused by a subducted seamount. Calculations revealed development of a distinct pair of fault-like shear zones, including a landward dipping forethrust fault initiated from the seamount top and a seaward dipping backthrust fault from the landward base of the seamount. Significant dome-shaped surface uplift was predicted above the thrust faults. Lesser-developed seaward dipping backthrust faults were calculated to develop under certain conditions. The overriding plate was calculated to deform in two stages: In Stage I, elastic deformation leads to the formation of fault-like shear zones. After major faults have cut through the entire plate, plastic deformation on faults dominates Stage II. On the subduction interface, compressional normal stress was calculated to increase on the landward leading flank of the seamount and decrease on the seaward trailing flank. These changes, together with associated stress singularities at seamount edges, could affect earthquake processes.
Author Posting. © American Geophysical Union, 2016. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 43 (2016): 8936–8944, doi:10.1002/2016GL069785.
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