제주도 동부해안 한동리 지역의 수문지질학적 연구 = Hydrogeology Study of Handong-ri area in the Eastern Coast of Jeju Island, Korea

다국어 초록 (Multilingual Abstract)

The purpose of this study is to understand the high saline water phenomenon of Handong-ri area in the eastern coast of Jeju Island, were investigate the tidal effect of groundwater level, variation of electric conductivity and temperature, geological logging on the monitoring wells, chemical water quality, and ratios of oxygen isotope of groundwater and seawater.
According to the results of geological logging on the monitoring wells, Geological structure of below the groundwater table consist of sandy layer, the hyaloclastites in forms of fragments and rubbles. They have stratums of the high porosity and good permeability that can act as aquifer layer. Hyaloclastites thicken more and more from inland to coast, so it expected that saline water flow easily into inland.
The tidal effect of HM1, 2 well are 0.43 and 0.23 respectively. Time lags are 56min and 102min respectively. The groundwater level of HM3 well, 5.1km distanced from coast, is little effected by the tide, but it find that daily variation of EC by tidal effect. Therefore HM3 is received effect by tide
It is monitored the hourly fluctuation of groundwater level from December 2000 to March 2002 at HL well distanced about 2.2km from coast. The maximum amplitude of groundwater level is 0.68m a day and difference of level by precipitation is 0.74m for monitoring period. Therefore variation of water level received effect by precipitation and tide.
Major ion and oxygen isotopic composition in lower layer of HM1, 2 well are similar to saline water and upper layer of HM3 well have little mixing with saline water. And major ion and oxygen isotopic composition at upper layer of HM1, 2 well are similar to the saline water, it represent the groundwater body by simple mix freshwater with saline water.
Results of EC and temperature geophysical logging represented that all the wells have a interface zone of freshwater and saline water. Depth of the interface zone is less than Ghyben-Herzberg's principle. The thickness of interface zone is only several meters at HM1, 3 well. But, EC increase stepwise at interface zone of HM 2 well, it showed that interface was developed by steps since stratums with good permeability was distributed with multi-steps both above and below interface zone.
Results in investigating variation of interface zone of freshwater and saline water represented that the hyaloclastites formed at below groundwater table is developing toward the coast; this area consisted of stratum of good permeability. Hyaloclastites is presumed the main path of the high salinity water. There are a lot of movement by the tide at upper layer. Salinity of lower layer spreads to upper up step in proportion to tidal energy.
Because of hydrogeological characteristics, Interface zone of freshwater and saline water is made, High salinity of groundwater occur in east coastal area of Jeju Island. Therefore, I think that high saline groundwater phenomenon is natural condition by simple mixing.

목차 (Table of Contents)

• 목차
• Summary
• Ⅰ. 서론
• Ⅱ. 연구방법
• Ⅲ. 연구지역의 개요
• 1. 지형
• 2. 지하수 부존 특성
• Ⅳ. 이론적 배경
• 1. 해안지역 대수층의 매카니즘
• 2. Piper diagram 해석 기법
• 3. 산소안정동위원소 원리
• 4. Ghyben-Herzberg 원리
• Ⅴ. 결과 및 고찰
• 1. 지표지질
• 2. 지하지질
• 3. 지하수위 변화
• 4. 수질특성
• 5. 전기전도도 및 온도 검층
• Ⅵ. 결론
• 참고문헌
• 부록