Velocity and displacement of Korean Peninsula after The 2011 Tohoku earthquake

On March 11, 2011, a magnitude 9.0 earthquake occurred in the Pacific Ocean off the Tohoku region, which greatly affected the crust of the Korean Peninsula. At the time of the Tohoku earthquake, the crust deformation of the Korean Peninsula moved about 30 mm in the eastward direction. This is the size corresponding to the annual average on the Korean Peninsula, and this displacement occurred in one day due to the earthquake. Therefore, in this study, the degree of impact of crustal movement on the Korean Peninsula before and after the Tohoku earthquake was analyzed using domestic and global GNSS observation data. The analysis was performed in two ways. The first was a time series analysis of the crustal movement on the Korean Peninsula based on the IGS observation station in order to globally observe the change in the crustal movement on the Korean Peninsula before and after the earthquake. Secondly, the movement of the inner crust of the Korean Peninsula was confirmed by analyzing the correlation of movement according to the distance from the epicenter. The analysis period is from January 1, 2005 to December 31, 2021. As a result, stations that moved in the southeast direction before the earthquake on the Korean Peninsula moved eastward after the earthquake. However, over time, it gradually moves in a southeasterly direction. The velocity was higher in the western region before the earthquake. At the time of the earthquake, the stations in the eastern area where closer to the epicenter moved more, but have since returned to a similar velocity to that before the earthquake. It seems to be recovering over time after the earthquake, but to be incompleted which means continuous monitoring is needed.