[SCG66-12] Effects of surface friction of subducting seamount on topographic evolution of the overriding accretionary prism: insights from sandbox experiment
Keywords:Sandbox experiment, Image analysis, Seamount subduction, Nankai accretionary prism off Muroto
In this study, we ran analog experiments in order to examine detailed topographic evolution and surface deformation of an accretionary prism due to seamount subduction. Digital Image Correlation (DIC), an image analysis method, was applied to surface observation, after success of recent applications of this technique to sandbox experiment to extract detailed and quantitative information (e.g., Adam et al., 2005; Yamada et al., 2006; Dotare et al., 2016; Koge et al., 2018). In this study, this technique was mainly used for visualization of the fault activity with seamount subduction.
Two seamount models with different surface friction, smooth (low friction) and rough (high friction) surface models, were used to investigate the response to the upper plate. The results suggest four findings: (1) large strike-slip faulting described in Dominguez et al (1998) were not observed, (2) the topographically curved region formed by subduction of smooth surface seamount recovered earlier than subduction of rough surface seamount, (3) the horizontally deformed area was within ± 10% of the radius of the seamount, (4) the splay fault, branched from décollement at landward edge of the rough surface seamount, continued the activity for longer time than the smooth surface seamount.
In this presentation, we will also report application to the natural example where topographic features downgoing and curvature zone exists in the Nankai accretionary prism off Muroto.