Seismicity and GPS constraints on crustal deformation in the southern part of the Korean Peninsula

Three years of continuous observations at 45 GPS sites in South Korea show horizontal deformation velocities are less than 3 mm/yr with respect to the stable South Korea block. These velocities and the associated horizontal strain rate reveal that South Korea is dominated by both ENE-WSW compression and NNW-SSE extension. Compared to the seismic strain rate in South Korea derived from recently recorded earthquake data (M-w > 4.0, 1936-2004), the principal horizontal axes of both strain rate tensors are nearly consistent, indicating that the seismicity can be used to improve GPS-derived deformation style and orientation. In addition, it also reflects that the occurrence of shallow earthquakes in South Korea is closely related with the horizontal strain.