Vertical velocity from the Korean GPS Network (2000–2003) and its role in the South Korean neo-tectonics

Ahmed M Hamdy,Bong Gon Jo,Pil-Ho Park

doi:10.1186/bf03352693

Abstract

Abstract In the absence of adequate leveling observations in South Korea, the vertical deformation has been investigated using the Korean Global Positioning System (GPS) Network data (2000-2003). Although the vertical components of the GPS velocities have been rarely used in crustal deformation studies because of their high noise level, the processing strategy employed here enhances the data quality and eliminates the seasonal effect. The obtained vertical velocity field shows that the maximum vertical velocity in the ITRF 97 reference frame is 3.3 mm/year (subsidence), which reflects a relatively low level of seismic activity in South Korea. Two deformation patterns were recognized; subsidence in the Okchun Basin, and uplift in its adjacent areas. This subsidence is due to the collision of Kyonggi Massif and Okchun Basin (part of the South China block) against the Yongnam Massif and Taebaeksan Basin (part of the North China block).

Highlights

The Korean Peninsula is located between the North andSouth China Blocks and the Japanese Island Arc as a part of the Eurasian or the Amurian Plate
The Korean Peninsula is standardly categorized into three main blocks of the Archaean and Proterozoic ages (Hurley et al, 1973; Reedman and Um, 1975; Ernst et al, 1988); these are, from north to south, the Nangrim-Pyongnam Massif (PM) and the Kyonggi Massif (KM), separated by the Imjingang Belt (IB) along the western part of the North Korea-South Korea border line, and the Yeongnam Massif (YM), separated from the Kyonggi Massif by the Okchun Belt (OB) (Fig. 1)
Taking account of the hypothesis of continent-continent collision (Cluzel et al, 1990, 1991a, b ; Cluzel, 1992; Chough et al, 2000) and the horizontal deformation tensors presented by Hamdy et al (2005), where YM-Taebaeksan Basin (TB) translates toward the NWN with clockwise rotation and KM-OB translates toward WSW with anticlockwise rotation, the combination of these strain tensors is considered to result in compression in the contact zone and its surroundings and the subsidence pattern of OB

Summary

Introduction

The Korean Peninsula is located between the North andSouth China Blocks and the Japanese Island Arc as a part of the Eurasian or the Amurian Plate. The recent tectonic environment in South Korea (Fig. 1) can be understood by considering two massifs—the Kyonggi Massif and the Yeongnam Massif—and two basins–the Okchun Basin and the Taebaeksan Basin (TB)–separated by five major A program for monitoring the crustal deformation in and around the Korean Peninsula has been designed combining geodetic data, geological structure, seismicity, and tectonic settings (Hamdy and Jo, 2002).

Results

Conclusion