Preliminary GPS results and a possible neotectonic interpretation for South Korea

Crustal velocities within South Korea were estimated using GPS data and interpreted in terms of neotectonics. Twenty months of data for the seven GPS stations in South Korea were analyzed to estimate velocities relative to Taejon (DAEJ), a central region of South Korea. From the time series of horizontal position of each station, we estimated site velocities with an accuracy of 0.5 mm/year or better mostly. The relative velocities within the Korean peninsula are very small (similar to1 mm/year), convertible to strain rates in the order of 0.01 ppm/yr. They indicate the Korean peninsula is likely to be tectonically more stationary than other countries in the East Asia, for example, Japan or Taiwan. The result of GPS analysis suggests a possibility that northwestward tectonic force due to the AM (Amurian plate)-PH (Philippine Sea plate) convergence affects the southeastern part of the Korean peninsula, of which the direction is curved due to internal faults in Korea, striking nearly perpendicular to the stress trend.