• Journal of Soil and Groundwater Environment
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• v.6 no.4
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• pp.97-112
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• 2001

The Section 12 of Groundwater Law stipulates that groundwater conservation zone should be regulated by the designation of conservation area and development restricted area, The most important policy for groundwater conservation and protection is to estimate and designate groundwater conservation zone. The groundwater classification map is utilized to determine the prime groundwater conservation areas, which delineate the first and the second ranked conservation areas of the map. According to the classification method of the Ministry of Construction and Transportation in 2000, groundwater quality for groundwater classification is classified with 4 levels based on the following conditions : (1) the present groundwater quality; (2) the potential usage as drinking water at present and in the future; (3) hydrogeological characteristics, and (4) the existence of pollution sources and activities. Throughout the initial analysis, the groundwater conservation areas are represented about 57.1$\textrm{km}^2$ in the groundwater classification map, which is 9.4% of Seoul Metropolitan Area. The management guidelines for groundwater conservation area are also developed referring to Cheju Province Groundwater Conservation Management Project and the guidelines by the Ministry of Construction and Transportation. But the specific administration and detailed technical survey should be prepared to efficiently manage the groundwater conservation area.

• Geophysics and Geophysical Exploration
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• v.14 no.1
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• pp.18-24
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• 2011

A multi-channel seismic reflection (MCS) survey was conducted in 2009 to explore the deep crustal structure of the Pacific Plate south of Hokkaido. The survey line happened to traverse a 250-km-wide Warm Core Ring (WCR), a current eddy that had been generated by the Kuroshio Extension. We attempted to use these MCS data to delineate the WCR fine structure. The survey line consists of two profiles: one with a shot interval of 200m and the other with a shot interval of 50 m. Records from the denser shot point line show much higher background noise than the records from the sparser shot point line. We identified the origin of this noise as acoustic reverberations between the sea surface, seafloor and subsurface discontinuities, from previous shots. Results showed that a prestack migration technique could enhance the signal buried in this background noise efficiently, if the sound speed information acquired from concurrent temperature measurements is available. The WCR is acoustically an assemblage of concave reflectors dipping inward, with steeper slopes (${\sim}2^{\circ}$) on th ocean side and gentler slopes (${\sim}1^{\circ}$) on the coastal side. Within the WCR, we recognised a 30-km-wide lens-shaped structure with reflectors on the perimeter.

• Tunnel and Underground Space
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• v.13 no.4
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• pp.270-278
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• 2003

Transparency on the Total System Performance Assessment (TSPA) is the key issue to enhance the public acceptance for a permanent high level radioactive repository. Traditionally, the study on features, events and processes (FEPs) and associated scenarios has been regarded as the starting point to open the communicative discussion on TSPA such as what to evaluate, how to evaluate and how to translate outcomes into more friendly language that many stakeholders can easily understand and react with. However, in most cases, it has been limited to one way communication, because it is difficult for stakeholders outside the performance assessment field to assess the details on the story of the safety assessment, scenario and technical background of it. Fortunately, the advent of the internet era opens up the possibility of two way communication from the beginning of the performance assessment so that every stakeholder can exchange their keen opinions on the safety issues. To achieve it, KAERI develops the systematic approach from the FEPs to Assessment methods flow chart. All information is integrated into the web based program named FEAS (FEp to Assessment through Scenario development) under development in KAERI. In parallel, two independent systems are also under development the web based QA(Quality Assurance) system and the PA(Performance Assessment) input database. It is ideal to integrate the input data base with the QA system so that every data in the system can checked whenever necessary. Throughout the next phase R&D starting from the year 2003, these three systems will be consolidated into one unified system.

• Tunnel and Underground Space
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• v.26 no.4
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• pp.304-315
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• 2016

In this study, the current horizontal stress characteristics of the Tertiary rock formations in the Pohang Basin are investigated on the basis of the in-situ rock stress measurements at depths from 75 m to 716 m of the 3 test boreholes in the Doumsan area, Pohang. The deep hydraulic fracturing stress measurement results indicated that the horizontal stress components in the test site appear far lower than the average ones by the linear fit for the data set measured from the other domestic sites. But, borehole scanning revealed clearly that lots of small and large scale borehole failures occurred due to the low strength characteristics of the existing rocks. To obtain more accurate and overall information on the horizontal stress direction, the integrated analysis combining the hydraulic fracturing stress measurement and borehole scanning data set were additionally carried out. The analysis results showed that in the upper sedimentary and the lower volcanic rock formation, the dominant orientations of the current maximum horizontal stress components were appeared in the range of $80^{\circ}{\sim}100^{\circ}$ (N80E~N80W) and $120^{\circ}{\sim}140^{\circ}$ (N60W~N40W), respectively. From this study result it was found that the maximum horizontal stress directions have a tendency to rotate in a clockwise direction as the rock formation changes with depth in the test site.

• The Journal of Engineering Geology
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• v.27 no.4
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• pp.383-392
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• 2017

Excessive abstraction of groundwater near streams for agricultural, domestic, or industrial use can significantly reduce the streamflow. Therefore, proper management of water resources must involve careful monitoring of groundwater use near streams. This study investigates the current status of groundwater intake plans in the Anseongcheon watershed, Korea, in order to understand the portion of groundwater wells according to distance from the stream and the distribution of wells near the stream. Among all the wells in the watershed, 20.5% were permitted and 31.3% were declared within 300m from the stream. In particular, among the wells located near streams, 11.4% were permitted and 88.6% were declared among the wells near streams. Therefore, the total amount of groundwater pumping rates from the declared wells is much higher than that from the permitted wells near the stream. Under current guidelines, investigations of the impact of groundwater use near a stream on streamflow depletion should only consider wells permitted by groundwater law. However, prudent management should also pay attention to declared wells, given their large number.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2018.10a
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• pp.55-55
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• 2018

한라산 동부지역에 위치한 삼다수 숲길은 삼나무, 편백나무, 곰솔림과 낙엽활엽수림으로 이루어진 숲이다. 현재 삼다수 숲길이 조성되어 관리되고 있으나 식물에 대한 정보가 거의 없는 실정으로 식물상을 조사하여 관리의 기초자료로 삼고자 수행하였다. 조사는 2018년 03월부터 2018년 08월까지 총 10회에 걸쳐 실시하였다. 조사 결과 삼다수 숲길에 생육하는 관속식물은 86과 183속 255종 11변종 4품종의 총 270분류군으로 조사되었다. 양치식물 12과 18속 30종 1변종 31분류군, 나자식물 2과 3속 3종 3분류군, 피자식물 72과 162속 222종 10변종 4품종으로 쌍자엽식물 64과 129속 176종 9변종 3품종 188분류군, 단자엽식물 8과 33속 46종 1변종 1품종 48분류군으로 구성되었다 이 중 한국특산식물은 5종, 제주특산식물 3종 외래식물이 13종 채집되었다. 식물구계학적특정식물은 5등급 3종, 4등급 11종, 3등급 23종, 2등급 12종, 1등급 26종 총 75종이 발견되었다. 국가 적색목록 식물은 위기(EN) 1분류군, 준위협(NT) 3분류군, 관심대상(LC) 4분류군, 미평가(NE) 2분류군이 조사되었다. 조사된 식물들의 휴면형은 H형이 62분류군으로 가장 많이 나타났고, MM형 40분류군, M형 31분류군, N형 29분류군, E형 3분류군, Ch형 22분류군, G형 51분류군, HH형 4분류군, Th형 28분류군으로 나타났다. 지하기관형은 R1 2분류군, R2 23분류군, R3 71분류군, R4 18분류군, R5 156분류군으로 R5가 57.85로 가장 높은 비율로 분포하였다. 산포기관형은 D4가 47.4%로 가장 높은 비율이였으며, 생육형(Growth form)은 직립형(e)이 53%로 가장 높은 비율로 분포 하였다.

• Geophysics and Geophysical Exploration
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• v.9 no.1
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• pp.108-113
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• 2006

Urban conditions, such as existing underground facilities and ambient noise due to cultural activity, restrict the general application of conventional geophysical techniques. At a tunnelling site in an urban area along an existing railroad, we used the refraction microtremor (REMI) technique (Louie, 2001) as an alternative way to get geotechnical information. The REMI method uses ambient noise recorded by standard refraction equipment and a linear geophone array to derive a shear-wave velocity profile. In the inversion procedure, the Rayleigh wave dispersion curve is picked from a wavefield transformation, and iteratively modelled to get the S-wave velocity structure. The REMI survey was carried out along the line of the planned railway tunnel. At this site vibrations from trains and cars provided strong seismic sources that allowed REMI to be very effective. The objective of the survey was to evaluate the rock mass rating (RMR), using shear-wave velocity information from REMI. First, the relation between uniaxial compressive strength, which is a component of the RMR, and shear-wave velocity from laboratory tests was studied to learn whether shear-wave velocity and RMR are closely related. Then Suspension PS (SPS) logging was performed in selected boreholes along the profile, in order to draw out the quantitative relation between the shear-wave velocity from SPS logging and the RMR determined from inspection of core from the same boreholes. In these tests, shear-wave velocity showed fairly good correlation with RMR. A good relation between shear-wave velocity from REMI and RMR could be obtained, so it is possible to estimate the RMR of the entire profile for use in design of the underground tunnel.

• Geophysics and Geophysical Exploration
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• v.10 no.1
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• pp.19-28
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• 2007

In this study, we propose a joint inversion method, using genetic algorithms, to estimate an S-wave velocity structure for deep sedimentary layers from receiver functions and surface-wave phase velocity observed at several sites. The method takes layer continuity over a target area into consideration by assuming that each layer has uniform physical properties, especially an S-wave velocity, at all the sites in a target area in order to invert datasets acquired at different sites simultaneously. Numerical experiments with synthetic data indicate that the proposed method is effective in reducing uncertainty in deep structure parameters when modelling only surface-wave dispersion data over a limited period range. We then apply the method to receiver functions derived from earthquake records at one site and two datasets of Rayleigh-wave phase velocity obtained from microtremor array surveys performed in central Tokyo, Japan. The estimated subsurface structure is in good agreement with the results of previous seismic refraction surveys and deep borehole data. We also conclude that the proposed method can provide a more accurate and reliable model than individual inversions of either receiver function data only or surface-wave dispersion data only.

• Geophysics and Geophysical Exploration
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• v.14 no.4
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• pp.316-323
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• 2011

To test the applicability of resistivity survey methods for the archaeological prospection of a large-scale tumulus, a three-dimensional resistivity survey was conducted at the $3^{rd}$ tumulus at Bokam-ri, in Naju city, South Korea. Since accurate topographic relief of the tumulus and electrode locations are required to obtain a high resolution image of the subsurface, electrodes were installed after making grids by threads, which is commonly used in the archaeological investigation. In the data acquisition, data were measured using a 2 m electrode spacing with the line spacing of 1 m and each survey line was shifted 1 m to form an effective grid of 1 m ${\times}$ 1 m. Though the 3-D inversion of data, we could obtain the 3-D image of the tumulus, where we could identify the brilliant signature of buried tombs made of stones. The results were compared with the previous excavation results and we could convince that a 3-D resistivity imaging method is very useful to investigate a large-scale tumulus.

• Economic and Environmental Geology
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• v.48 no.1
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• pp.89-101
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• 2015

The sour gas is natural gas containing components such as hydrogen sulphide and carbon dioxide that form acids when mixed with water. Element sulfur precipitates from sour gas when reservoir pressure and temperature decrease. According to the International Energy Agency, about 43% of the world's natural gas reserves(2,580 tcf or 73.057 tcm), excluding North America, are sour. The sour gas is often derived from the Germanic word 'sauer or acidic' and the etymology referred to as 'sour'. Sour gas requires special handling and infrastructure because it contains significant amounts of hydrogen sulphide, making it highly corrosive, flammable and explosive, and there fore more costly and dangerous to process. So the business of sour gas is affected by two important factors: the economic value of the gas, and the methods used in its production. According to be analyzed in the academic literature to sour gas(2000~2014) by the program of 'web of science', the research activities 145 papers in sour gas.