Deformation and faulting of subduction overriding plate caused by a subducted seamount. Issue 17 (3rd September 2016)

• Record Type: Journal Article
• Authors: Ding, Min; Lin, Jian
• Is Part Of: Geophysical research letters. Volume 43:Issue 17(2016)
• Page Start: 8936
• Page End: 8944
• Publication Date: 2016-09-03
• Subjects: seamount -- overriding plate -- elastoplasticity -- fault formation -- earthquakes; Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1002/2016GL069785
• Languages: English
• ISSNs: 0094-8276

Abstract

Abstract: 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. Key Points: Subducted seamount could induce complex thrust fault system, including distinct forethrust and backthrust faults With background horizontal compression due to backstop, subducted seamount might strengthen forethrust but suppress backthrust faults Inhomogeneous normal stress changes on seamount flanks and edges could contribute to the complexity of seamount‐earthquake relationship