In the Mt. Kwangduk area, Ansan, Kyunggi-do, a hydrogeologic study was carried out with resistivity measurements from 33 points along 7 profiles with Schlumberger array and drilling from 18 points in the metamorphic rock area, which is composed of the Precambrian muscovite schist or graphite schist. The study area is covered by 25 meter thick Quaternary alluvium. The V.E.S.curves of resistivity showed N10-45° W and N10-20° E trending low apparent resistivity zone. This trend of low resistivity values is interpreted as shattered zone. The drilling data including lithologic log and exact depths of basement rocks allow to determine yield capacity, coefficients of permeability and coefficients of transmissibility. The groundwater yield capacity is related to the weathered zone and apparent resistivity anomaly but not related to the well depth. Large yield capacity of groundwater is interpreted to be the same trend as the direction of joint development and topographic relief.