Viscoelastic modelling reveals correlation between GNSS-derived deformation rates after the 2011 Tohoku-Oki earthquake and lithospheric thickness in the southern Korean Peninsula
True post-seismic (TPS) (A–E) principal strain rate orientations, (F–J) dilation rates (1/yr) and (K–O) maximum shear strain rates (1/yr). The red dashed lines demarcates the major tectonic units in the SKP.Abstract
The 2011 Tohoku-Oki earthquake caused significant post-seismic (PS) deformations in a broad region in East Asia including the southern Korean Peninsula (SKP). In this study, we aim to better characterize the PS deformations in the SKP and understand the underlying physical mechanisms for them using linear Maxwell viscoelastic numerical models. We computed the annual mean velocities by applying the extended linear trend modelling technique to the publicly available Global Navigation Satellite System data. We then derived yearly PS deformation rates for the first five years after the 2011 Tohoku-Oki earthquake using a least-square collocation method. Our findings, along with the tectonic history of the SKP, suggest that the regions of elevated “true postseismic” maximum shear strain rates might have thinner or weakened lithosphere, which can be one of the consequences of the pervasive granitic intrusions in those regions.