Imaging the Three-Dimensional Crust of the Korean Peninsula by Joint Inversion of Surface-Wave Dispersion and Teleseismic Receiver Functions

Abstract

Abstract A detailed study of the 3D variation of shear-wave velocities in thesouthern part of the Korean Peninsula is made by combining high-frequency surface-wave tomography results of Cho et al. (2006b) with teleseismic P -wave receiverfunctions at 80 locations on the peninsula. Receiver functions were derived fromhigh-gain acceleration, short-period, and broadband digital data streams of the KoreaMeteorological Administration ( KMA ) and Korean Institute for Geosciences andMineral Resources ( KIGAM ) networks. Vertical cross sections trace the lateral vari-ation in the depth to the Moho, the variation of low velocities near the surface, andthe variable thickness of the transition from surface velocities to midcrustal veloci-ties. The derived crustal structure provides new insights on the evolution of theKorean crust.Introduction Geophysics, and seismology, in particular, provides in-direct means for assessing the larger- to local-scale, present-day architecture of continental masses through remote sens-ing (Bostock, 1999). Although field geology has providedvast information on the upper crust, mapping variations instructure in depth through geophysical investigation is aprincipal step in unraveling and understanding the evolutionof the continental lithosphere. In an area whose genetic pro-cess is relatively unknown, such as the Korean Peninsula, itis important to add geophysical constraints to reveal the con-tinental evolution.The Korean Peninsula (Fig. 1), situated at the easternmargin of the Eurasian continent, is a tectonic assemblageof two Phanerozoic mobile belts, the Imjingang belt and theOkcheon (fold) belt; three Precambrian basement terrains,Nangrim, Gyeonggi, and Yeongnam Massifs from north tosouth; and one volcanoclastic basin, that is, Gyeongsang ba-sin (Reedmann and Um, 1975; Cluzel