Ocean bottom pressure contribution to vertical crustal displacement in the Korean Peninsula

Abstract:

Vertical crustal displacements over seasonal and inter-annual time scale are mostly associated with variations of surface loading from atmospheric pressure, ocean bottom pressure and terrestrial water storage. Observing crustal displacement and understanding its causes are important for studies of global changes and crustal stress and strain. In this study, we examine vertical crustal displacement in the Korean Peninsula with GPS observations and model predictions. We use 10 permanent GPS stations data during 10 years (Jan. 1, 2005 ~ Dec. 31, 2014) and estimate their positioning time series based on Precise Point Positioning (PPP). Vertical crustal displacements at the GPS stations are also modeled from surface loading data. For atmospheric pressure loading, we combine in-situ data observed by Korean Meteorological Agency (KMA) and ECMWF model output. Since ocean bottom pressure loading is likely important in the Peninsula, we also use ECCO ocean bottom pressure data. We find that the vertical displacements observed by GPS show strong seasonal variations (40~50 mm), and they are in good agreement with model predictions from atmospheric and ocean bottom pressure. In addition, ocean bottom pressure contribution to the vertical displacement is much larger than atmospheric effect due to large seasonal variations of ocean bottom pressure in the Yellow sea.