4:30 PM - 4:45 PM
[SSS31-09] Crustal tectonic stress and poroelastic relaxation of the Mw 9.1 tohoku earthquake
Keywords:pore pressure, poroelastic relaxation, coulomb stress
By using various input of slip model, we calculate undrained coseismic pore pressure and coulomb stress change due to the earthquake (King, Stein, & Lin, 1994; Cocco & Rice, 2002) and its poroelastic relaxation by using green's function proposed by (Kalpna & Chander, 2000). The strain and stress due to slip on the fault are calculated by using analytical expression of (Okada, 1992) and consider stress-strain relation for an isotropic form of Hooke's law, respectively. We find that pore pressure changes following the tohoku-oki earthquake is increased through relaxation in the dilatation region which further modified coseismic coulomb stress in surrounding region. We estimates the pore pressure variation from the first 50 days following the tohoku earthquake has change from 7.08 MPa to 2.62 MPa in the dilatation region, and in the compression region, it change from -9.37 MPa to -3.46 MPa.