In order to investigate the relationship between the distribution pattern of subsurface geological features and the Bouguer anomaly in the Eumseong area, Chungbuk Province, gravity values were measured from 290sites using Worden gravity meter. The study area consists of (1) Pre-Cambrian metamorphic rocks which were intruded by the Jurassic igneous rocks, (2) the Mesozoic Chopyeong and Baegyari Formation, and (3) the Basalt and Andesite which intruded the Cfiopyeong Formation. Terrain correction value using 0.5km X 0.5km blocks is an average of 0.9mgal (max. 1.8mgal, min. 0.1mgal). The depth of density boundary in the study area were calculated by power spectrum analysis with double Fourier transform and FFT. Downward continuation of gravity was performed using the sinχ/χ convolution method. To minimize the Gibbs phenomenon associated with the downward continuation, Hamming filter was used. The value of Bouguer anomaly is-8mgal to 4mga1. Direction of the regional anomaly is the NEW whose trend is parallel with regional structural features. Residual anomaly is low in sedimentary rocks of middle part and igneous rocks regions of eastern and western parts of the study area, whereas it is high in metamophic rocks and andesite vein of middle part. Mean depth of the density boundary is 1420m, and undulation aspect of the subterrain was highest in andesite region. The boundary depth is increasing from Chopyeong Formation to Baegyari Formation.

• 송무영
• 김현섭