Contemporary deformation and strain analysis in South Korea based on long-term (2000-2018) GNSS measurements

South Korea forms the Korean Peninsula and is considered to be tectonically more stable than the other regions of Eastern Asia. Global Navigation Satellite System (GNSS) sites installed in the country contribute to geoscientific studies on contemporary deformation, strain pattern, and current kinematics of tectonic blocks. In the current study, we used long-term GNSS measurements (from 1 January 2000 to 31 December 2018) to study block-wise geodetic deformation and strain pattern of the country, including the co-seismic effect of the 2011 Tohoku-Oki (TO) Earthquake. Measured velocities of GNSS sites are modelled via exponential smoothing method to analyse the GNSS time-series and obtain the secular tectonic crustal deformation. The analysis of strain pattern and vertical displacements indicates that extensional deformation followed compressional deformation from the northern Korean blocks to the southern Korean blocks. Finally, we examined the angular velocity and pole of rotation of the South Korean blocks using pre-seismic and post-seismic displacements of the GNSS sites. The results indicate that the angular velocity of the northern blocks was lower, while the southern block velocity is higher after the TO earthquake. We believe that the integrated approaches applied in the study would provide better insights into the active deformation of South Korea.