3:30 PM - 3:45 PM
[SCG57-29] Modeling viscoelastic deformation and strain anomaly around the Ou Backbone Range after the 2011 Tohoku-oki earthquake
Keywords:the Tohoku-oki earthquake, the northeastern Japan arc, viscoelastic deformation, the Ou Backbone Range, strain anomaly
We develop a finite element model of the viscoelastic deformation processes after the Tohoku-oki earthquake, considering the realistic crustal and mantle structures, and coseismic fault slip distribution (Iinuma et al., 2012). Our numerical results show that significant extensional viscous deformation occurs in the low-viscosity regions in the crust and upper mantle. This deformation causes significant subsidence in the back-arc region and Ou Backbone Range, but uplift near the Pacific coast. We also try to reproduce the decreases in areal strain along the Ou Backbone Range observed by Miura et al. (2014). In the case where low viscosity zones are extended to the shallower part of the crust, we can reproduce the areal strain decrease which is caused by contraction along the N-S direction. In our model, we cannot reproduce the expansion of areal strain decrease over time along the arc observed by Miura et al. (2014). To model this phenomenon, we would probably need to consider afterslip after the Tohoku-oki earthquake.