Strain accumulation in South Korea inferred from GPS measurements

Shuanggen Jin,Pil-Ho Park

doi:10.1186/bf03351950

Abstract

AbstractMonitoring the variation of the crustal strain is a key issue to understand the physical process of crustal tectonic activities. In this paper, GPS data for the period from March 2000 to February 2004 were analyzed to quantitatively investigate the plate deformation patterns and distributions in the South Korean peninsula. The results show two anomalous rates of strain accumulation in South Korea, a W-E compression accumulation of crustal strain in the East and West parts, and a N-S extension strain accumulation in the middle part along the longitude of about 127.5°E. In addition, the GPS-derived seismic moment accumulation rate is significant and consistent with recent historic earthquakes and fault zones in South Korea. The most anomalous seismic moment rates are in the middle part (about 127.3°E, 35.5°N), North edge (about 128.0°E, 38.0°N) and Northeast part (about 128.5°E, 37.3°N) of South Korea, indicating a high earthquake risk.

Highlights

The Korean peninsula is located in the northeastern Asia margin, a convergent region of Chinese continent and the Japanese Island Arc, which is characterized by the subduction of the Philippine Sea plate and the Southeastward expulsion of Eurasian plate (Molnar and Tapponnier, 1975; Zonenshain and Savostin, 1981; Kato et al, 1998a; Kogan et al, 2000, Jin and Zhu, 2003)
We divide the South Korean peninsula into 32 small quadrangle subnetworks where the obvious anomalous site PNJU is excluded at the Northwest edge and use the horizontal velocity field of the Korea GPS Network (KGN) in the Amurian plate fixed reference frame to estimate the strain parameters of each subnetwork
Concluding Remarks The current kinematics of crustal motions in South Korea is analyzed in term of strain rates based on four years of continuous GPS observations (2000–2004)

Summary

Introduction

The Korean peninsula is located in the northeastern Asia margin, a convergent region of Chinese continent and the Japanese Island Arc, which is characterized by the subduction of the Philippine Sea plate and the Southeastward expulsion of Eurasian plate (Molnar and Tapponnier, 1975; Zonenshain and Savostin, 1981; Kato et al, 1998a; Kogan et al, 2000, Jin and Zhu, 2003). Hamdy et al (2005) initially analyzed the horizontal deformation of South Korea using 3-year GPS data, but didn’t show the high-resolution deformation pattern and strain accumulation. Monitoring the spatial variation of the strain and comprehensive understanding of strain accumulation pattern are beneficial to reveal the physical process of crustal tectonic activities and to evaluate the earthquake risk.

Results

Conclusion