Sung-Joon Chang and Chang-Eob Baag
Moho depth and crustal V _p /V _s variation in Southern Korea from teleseismic receiver functions; implication for tectonic affinity between the Korean Peninsula and China
Bulletin of the Seismological Society of America (October 2007), 97(5):1621-1631

Abstract:
We estimated Moho depths and V _P /V _S ratios of the crust under 21 broadband stations in southern Korea by using a grid search in the crustal thickness-V _P /V _S ratio (H-kappa ) domain. The Moho depth varies from 25.9 km to 32.5 km, and the V _P /V _S ratio ranges from 1.71 to 1.82 inland. Moho depths in the southernmost area of the Korean Peninsula were estimated shallower than those of the previous results obtained assuming a Poisson solid in the joint analysis of receiver functions and surface-wave dispersion. This southernmost area is roughly in accord with the Yeongnam massif, where relatively high V _P /V _S ratios of 1.78-1.82 are estimated. On the contrary, comparatively low V _P /V _S ratio measurements (1.71-1.76) are generally distributed in the Gyeonggi massif, which is located in the central area of the Korean Peninsula. The major factor for the high V _P /V _S ratios in the Yeongnam massif is thought to be the plagioclase-rich mafic composition of the lower crust rather than partial melting or crustal fluids, because high crustal S-wave velocities are reported in the Yeongnam massif. The mafic composition might have been supplied by the magmatic underplating. From the clearly divided feature of V _P /V _S ratios in southern Korea and the V _P /V _S ratio similarities between southern Korea and China, it seems that the Yeongnam massif might be related to the Sino-Korea craton, whereas the Gyeonggi massif is related to the Yangtze craton.