9:45 AM - 10:00 AM
[SSS32-16] Insight into poroelastic rebound deformation following the tohoku earthquake
Keywords:poroelastic rebound, undrained and drained Poisson's ratio, grid search, co- and after-slip inversion
Therefore, poroelastic rebound should be included in the analysis of early postseismic deformation following the Tohoku earthquake. Previous modeling studies in poroelastic rebound used various values for undrained and drained Poisson’s ratio (e.g., Peltzer, Rosen, Rogez, and Hudnut (1998); Jonsson, Segall, Pedersen, and Bjornsson (2003)). Instead of just assuming the values of drained and undrained Poisson’s ratio, we use grid search to estimate undrained and drained Poisson’s ratio value by combining forward calculation of poroelastic rebound and afterslip inversion of inland and offshore GPS data. In total, we build 400 poroelastic rebound model with different combination of undrained and drained Poisson’s ratio. Grid search approach obtained optimum value of 0.23 and 0.29 for drained and undrained Poisson’s ratio, respectively. Poroelastic rebound produced by the optimum value of drained and undrained Poisson’s ratio estimated horizontal displacement up to 0.28 m in the rupture area. Majority of large uplift due to poroelastic rebound occurred in and around the vicinity of the rupture area where maximum uplift estimated up to 0.37 m around the maximum slip area of the mainshock.