Coseismic and postseismic crustal deformations of the Korean Peninsula caused by the 2011 Mw 9.0 Tohoku earthquake, Japan, from global positioning system data

摘要

We present the first analysis on the crustal deformation in the Korean peninsula by the 2011 Tohoku earthquake. The great Mw 9.0 earthquake extended the Korean peninsula along E-W direction even though it is at a distance longer than one thousand kilometres from the epicentre. The coseismic surface displacements from 1.0cm (in the southwestern part) to 5.4cm (in the eastern part) were detected by continuous GPS observation. The estimated coseismic strains from the displacements correspond to approximately 6-28years of accumulated strains in the Korean peninsula. The postseismic displacements during 162days after the earthquake showed 43-48% of the coseismic displacements. The results imply that the contractional strains of the Korean peninsula have been accumulated by the locked subduction zone off, and a part of accumulated strains has been released by the mainshock and the afterslip of the 2011 Tohoku earthquake.