• Title/Summary/Keyword: geological boundary

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Characterization on the Geological Structures and Geothermal Gradient Distribution in the Yusong Area (유성온천지역의 지질구조 및 지온분포 연구)

  • 정지곤;서만철;김경수;황형중
    • The Journal of Engineering Geology
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    • v.7 no.3
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    • pp.173-189
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    • 1997
  • A study on the geological structure and geothermal gradient distribution was carried out to evaluate the feasibility of developing a new geothermal field in the Yusong area. It is suggested that geothermal water in the Yusong area is closely related with faults, dykes, and their dipping characteristics with the study of geothermal gradient distribution. A fault of EW direction locates in northern boundary of the study area and another fault of N40{\citc}W$ crosses the EW fault at the western part of the study area. Locations of faults are recognized quite well by lineaments, geophysical exploration and geothermal gradient distribution characteristics. Three sets of dyke are found in the study area. According to the result of the geothermal gradient distribution study, the location of geothermal anomaly belt and dykes coincide each other, and the area has the temperature gradient of larger than 3$^{\circ}C$ between the depths of 0.5m and 1.0m below ground surface. The thermal anomaly belt those temperature gradient is larger than 2.5$^{\circ}C$ between the depths of 0.5m and 1.Om below ground surface is expected in the direction of N80{\citc}W$ in the study area. The dirping of dyke is almost vertical according to the linear distribution of dykes on surface and the results of geophysical survey. From the distribution of geothermal anomaly belt and the locations of dyke, three locations for the development of hot spring water could be recommended and the depth that ensure over 4$0^{\circ}C$ geotheraral water is estimated as 170~200m below the ground surface.

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Geophysical Studies on Major Faults in the Gyeonggi Massif : Gravity and Electrical Surveys In the Gongju Basin (경기육괴내 주요 단층대의 지구물리학적 연구: 공주분지의 중력 및 지전기 탐사)

  • Kwon Byung-Doo;Jung Gyung-Ja;Baag Chang-Eob
    • The Korean Journal of Petroleum Geology
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    • v.2 no.2 s.3
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    • pp.43-50
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    • 1994
  • The geologic structure of Gongju Basin, which is a Cretaceous sedimentary basin located on the boundary of Gyeonggi Massif and Ogcheon Belt, is modeled by using gravity data and interpreted in relation with basin forming tectonism. The electrical survey with dipole-dipole array was also conducted to uncover the development of fractures in the two fault zones which form the boundaries of the basin. In the process of gravity data reduction, the terrain correction was performed by using the conic prism model, which showed better results specially for topography having a steep slope. The gravity model of the geologic structure of Gongju basin is obtained by forward modeling based on the surface geology and density inversion. It reveals that the width of the basin at its central part is about $4{\cal}km$ and about $2.5{\cal}km$ at the southern part. The depth of crystalline basement beneath sedimentary rocks of the basin is about $700{\~}400{\cal}m$ below the sea level and it is thinner in the center than in margin. The fault of the southeastern boundary appears more clearly than that of the northwestern boundary, and its fracture zone may extended to the depth of more than $1{\cal}km$. Therefore, it is thought that the tectonic movement along the fault in the southeastern boundary was much stronger. These results coincide with the appearance of broad low resistivity anomaly at the southeastern boundary of the basin in the resistivity section. The fracture zones having low density are also recognized inside the basin from the gravity model. The swelling feature of basement and the fractures in sedimentary rocks of the basin suggest that the compressional tectonic stress had also involved after the deposition of the Cretaceous sediments.

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Surface geophysical surveys the northern part of the Yongdong basin (Cretaceous), Korea (영동분지(백악기) 북부 지역에 대한 지표물리탐사)

  • Kim, Ji-Su;Han, Soo-Hyung;Rhee, Cheol-U;Kim, Bok-Cheol;Ryang, U-Heon
    • Journal of the Korean Geophysical Society
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    • v.5 no.4
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    • pp.329-336
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    • 2002
  • Electrical resistivity dipole-dipole, seismic refraction, and seismic reflection methods were performed to delineate the boundaries the Yongdong basin(Cretaceous) in terms of physical properties and to ultimately identify the margin architectures of the faults or unconformities. Higer resistivities (approximately >2000 ohm-m) most likely originate from the basement of the basin, contrasting with the lower resistivities from infilled sedimentary rocks. Faults at the eastern margin and unconformities at the western boundary are characterized as high-slope($70^{\circ}$) and gentle-slope($30^{\circ}$) gradients in the resistivity sections, respectively Such features for the boundaries are also suggested by the lower values of seismic velocity and resistivity for the western margin.

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The Role of Evaluative Language in News Translation : Focusing on Soft and Hard News

  • Ban, Hyun;Noh, Bokyung
    • International Journal of Advanced Culture Technology
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    • v.6 no.2
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    • pp.65-71
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    • 2018
  • In the digital era, news consumption is not confined in geological boundaries. Technological advances bring the instant dissemination of news into life and allow news audience to consume events that occur far away almost in real time. The transmission has blurred the boundary between traditional media and new media, and the one between physical and virtual world. That is, what if a journalist applies news framing to the news translation process? This paper aims to investigate the gap between the ST and the TT created when the source news texts undergo a translation process. To achieve this aim, the appraisal theory developed by White (2003) is employed to identify a difference between the ST and the TT. Furthermore, we have attempted to identify differences between soft news stories and hard news stories while the STs from both news stories are translated into the TTs. Two time-sensitive events, Hugh Grant's marriage and a U.S. and North Korea summit, were selected. The former (a soft news story) is extracted from the Telegraph and the latter (a hard news story) is from the Washington post. As a result, it was found that such strategies as attitude, engagement, and judgment were used when the source news texts from the hard news story are translated into the target news texts. Under the appraisal theory, the strategies involve evaluative language which refers to positive or negative language that judges the worth of entities. In general, it is said that a journalist frames the SS (especially from the hard news story) to convey his ideology to news consumers. Hypothetically, we assume that a similar framing process takes place in deriving the TT from the SS of the hard news story. Thus, we could conclude that the TT from the hard news story differs from the TT from the soft news story and that the difference can be explained within the framework of White's appraisal theory.

Stochastic Simulation of Groundwater Flow in Heterogeneous Formations: a Virtual Setting via Realizations of Random Field (불균질지층내 지하수 유동의 확률론적 분석 : 무작위성 분포 재생을 통한 가상적 수리시험)

  • Lee, Kang-Kun
    • Journal of the Korean Society of Groundwater Environment
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    • v.1 no.2
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    • pp.90-99
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    • 1994
  • Heterogeneous hydraulic conductivity in a flow domain is generated under the assumption that it is a random variable with a lognormal, spatially-correlated distribution. The hydraulic head and the conductivity in a groundwater flow system are represented as a stochastic process. The method of Monte Carlo Simulation (MCS) and the finite element method (FEM) are used to determine the statistics of the head and the logconductivity. The second moments of the head and the logconductivity indicate that the cross-covariance of the logconductivity with the head has characteristic distribution patterns depending on the properties of sources, boundary conditions, head gradients, and correlation scales. The negative cross-correlation outlines a weak-response zone where the flow system is weakly responding to a stress change in the flow domain. The stochastic approach has a potential to quantitatively delineate the zone of influence through computations of the cross-covariance distribution.

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The DFN-DEM Approach Applied to Investigate the Effects of Stress on Mechanical and Hydraulic Rock Mass Properties at Forsmark, Sweden (암반균열망-개별요소법 수치실험을 통해 살펴본 스웨덴 포쉬마크지역 암반의 역학적 및 수리적 물성에 초기응력이 미치는 영향)

  • Min, K.B.;Stephansson, O.
    • Tunnel and Underground Space
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    • v.21 no.2
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    • pp.117-127
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    • 2011
  • The purpose of this study is to demonstrate the effect of in-situ rock stresses on the deformability and permeability of fractured rocks. Geological data were taken from the site investigation at Forsmark, Sweden, conducted by Swedish Nuclear Fuel and Waste Man-agement Company (SKB). A set of numerical experiments was conducted to determine the equivalent mechanical properties (essentially, elastic moduli and Poisson's ratio) and permeability, using a Discrete Fracture Network-Discrete Element Method (DFN-DEM) approach. The results show that both mechanical properties and permeability are highly dependent on stress because of the hyperbolic nature of the stiffness of fractures, different closure behavior of fractures, and change of fluid pathways caused by deformation. This study shows that proper characterization and consideration of in-situ stress are important not only for boundary conditions of a selected site but also for the understanding of the mechanical and hydraulic behavior of fractured rocks.

A Study of Coarse Bed Materials in Small Streams in Rocky Mountains (로키 산맥 소하천의 조립질 하상 퇴적물에 관한 연구)

  • Kim, Jong-Wook
    • Journal of the Korean Geographical Society
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    • v.33 no.1
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    • pp.1-16
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    • 1998
  • This study surveyed intensively the relationships between grain size of coarse bed materials and some principal factors in channel system, drainage area and channel slope, in Rocky Mountains. The result of this research shows that there are statistically significant relationships between these factors. Generally, the grain size and the channel slope exponentially decreased in the study area with the increase in drainage area. However, there are great differences in grain size and channel slope between upstream and downstream channels. The boundary lines are commonly located at near the mouth of canyon. From these results, it can be concluded that the bed material characteristics and the channel slope are strongly influenced by the geological and geomorphological background of the drainage basin in this study area.

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Surface Geophysical Survey for Delineation of Weathered Zone of Chojeong Area and Investigation of Fault Fracture Zones (초정지역의 풍화대 조사 및 단층파쇄 지역의 불연속면 조사를 위한 지표물리탐사)

  • Kim, Ji-Soo;Han, Soo-Hyung
    • The Journal of Engineering Geology
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    • v.17 no.4
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    • pp.517-523
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    • 2007
  • Geophysical surveys(seismic refraction, electrical resistivity, and ground penetrating radar) were performed to delineate the weathering zone associated with vadose water in Chojeong area and investigate the fault related fracture zones. On the basis of seismic velocity structures, weathering layer for the southwestern part is interpreted to be deeper than for the northeastern part. The depth to bedrock(i.e., thickness of weathered zone) from seismic refraction data attempted to be correlated with drill-core data and groundwater level. As for the investigation of geological discontinuities such as fault related fracture zone, seismic refraction, electrical resistivity, and ground penetrating data are compositely employed in terms of velocity and resistivity structures for mapping of surface boundary of the discontinuities up to shallow depth. Surface boundaries of fracture zone are well indicated in seismic velocity and electrical resistivity structures. Accurate estimation of weathered zone and fracture zone can be successfully available for mapping of attitude of vadose water layer.

Dipole-Dipole Resistivity Survey on the Side of Han River near Nanjido Landfill (난지도에 인접한 한강변에서의 쌍극자-쌍극자 전기탐사)

  • Lee, Kiehwa;Kwon, Byung-Doo;Oh, Seok-Hoon;Kim, Cha-Seop
    • Economic and Environmental Geology
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    • v.29 no.3
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    • pp.335-343
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    • 1996
  • The dipole-dipol electrical resistivity survey was conducted to investigate the probable contamination of the Han river by leachate from the near-by Nanjido Landfill. The survey line of 3 km was set along the unpaved road toward the Han river. For the convenience of the field work, the survey line was divided into four segments. The complete two-dimensional resistivity section was constructed by connecting the inversion result of each segment. Gravity survey was also carried out along the profile parallel to the resistivity line. Near surface resistivity generally appeared to be of very low value in most part of the survey area and the boundary between the alluvium layer and underlying basement rocks is well discriminated on the resistivity section. These results agree well with those of the preceding Schlumberger depth sounding made at adjacent area by Lee and fun (1995). The variation of thickness of the alluvium layer delineated by gravity anomaly profile also correlates well with the result of the resistivity survey on the qualitative basis. The problem of contamination by leachate from the Nanjido Landfill, where various waste materials have been dumped without any proper treatment facilities, has been remains unsolved yet. Therefore, we present the most probable passages of leachate flow based on the survey results and have briefly discussed about measure for contamination control. Considering the thickness of alluvium and the possible existence of fractured zone, the middle point between 1st and 2nd landfill and the midst of 1st landfill are the most hazardous regions to make leachates flow into the Han river. Since large amounts of leachates are observed from the test wells located on the lines extending from the border between the 1st and 2nd landfill and the middle of the lst landfill, contamination protection barriers are strongly recommended near these regions.

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A Constitutive Model Using the Spacing Ratio of Critical State (한계상태 간격비를 이용한 구성모델)

  • Lee, Seung-Rae;O, Se-Bung;Gwan, Gi-Cheol
    • Geotechnical Engineering
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    • v.8 no.2
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    • pp.45-58
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    • 1992
  • An elasto-plastic constitutive model for geological materials, which satisfies the flezibility and stability at the same time, can be used in a number of geotechnical problems. Using the spacing ratio of critical state, a flexible model is proposed based on the stability of modified Camflay model. The spacing ratio of critical state can be simply evaluated, and practically used in describing the undrained shearing behavior of clay. The proposed model has precisely predicted the stress paths and stress -strain relationships, compared with the modified Camflay model, with respect to undrained triaxial test results. Besides, the effects of strain rate, creep, and relaxation can also be considered. Using the quasi-state boundary surface, the constitutive relations are well predicted. Therefore, it is found that the assumption of associative flow rule is well posed for undrained behavior of normally consolidated clay.

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