• Title/Summary/Keyword: escarpment

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Influence of undercut and surface crack on the stability of a vertical escarpment

  • Banerjee, Sounik K.;Chakraborty, Debarghya
    • Geomechanics and Engineering
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    • v.12 no.6
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    • pp.965-981
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    • 2017
  • Stability of vertical escarpments has been the subject of discussion for long time. However, available literature provides scarce knowledge about the effect of the formation of undercut and surface cracks on the stability of a vertical escarpment. The present study deals with a systematic analysis of the effect of surface cracks and undercut on slope stability using finite element based lower bound limit analysis. In the present analysis, the non-dimensional stability factor (${\gamma}H/c$) is used to inspect the degrading effect of undercut and cracks developed at different offset distances from the edge of the vertical escarpment. Failure patterns are also studied in detail to understand the extent and the type of failure zone which may generate during the state of collapse.

The 29 May 2004 Offshore Southeast Coast of Korea Earthquake Sequence: Shallow Earthquakes in the Ulleung Back-arc basin, East Sea (Sea of Japan)

  • Kim, Won-Young;Noh, Myung-Hyun;Choi, Ho-Sun
    • Journal of the Korean Geophysical Society
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    • v.9 no.3
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    • pp.249-262
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    • 2006
  • The 29 May 2004 offshore Uljin, Korea earthquake was predominantly thrust-faulting at a depth of approximately 12 (±2) km. The mainshock attained the seismic moment of M0 =5.41 (±1.87)  1016 N m (Mw = 5.1). The focal mechanism indicates a subhorizontal P-axis trending 264° and plunging 2°. The orientation of P- and T-axis is consistent with the direction of absolute plate motion generally observed within the plates, hence the cause of the May 29 shock is the broad-scale stress pattern from the forces acting on the downgoing slab along the Japan trench and inhibiting forces balancing it. The 29 May 2004 earthquake occurred along a deep seated (~12 km), pre-existing feature that is expressed on the surface as the basement escarpment along the western and southern slopes of the Ulleung basin. The concentrated seismicity along this basement escarpment suggests that this feature may qualify as a seismic zone - the Ulleung basement escarpment seismic zone (UBESZ).

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A study on the Characteristics of Flows over Isolated Cone-type Hills (독립된 원뿔형 산악지형의 기류 특성에 관한 연구)

  • Cho, Kang-Pyo;Hong, Sung-Il;Cho, Gi-Sung;Lee, Ok-Jin
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2008.04a
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    • pp.222-227
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    • 2008
  • Complex terrain like hill, mountain, and escarpment etc. makes complex air flow. This topographic condition will affect not only speed but also turbulence of wind over the complex terrain. In this paper, turbulence intensities are considered to investigate characteristics of wind over cone-type hills. There are five simple hill models with different slope 0.1${\sim}$0.5(tan${\theta}$) for wind tunnel test. It was observed through wind tunnel tests that turbulence intensities of down-slope wind at the end of the 3-Dimensional hills remarkably increased but ones of windward slope wind at the front side of the hills slightly increased. Also, turbulence intensities proportionally increased with slope of the cone-type hills.

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A Study of the Potential Shelters in the Lunar Lava Tubes (달 동굴의 잠재적 주거환경에 관한 연구)

  • Oh, Jongwoo
    • Journal of Satellite, Information and Communications
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    • v.12 no.3
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    • pp.41-49
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    • 2017
  • This paper will describe lunar lava tubes' five analyzed fields, such as geology, geomorphology, internal configuration, stability, communication and habitats requirements. This research gets through qualitative and qualitative data analysis as following results. A huge size and configuration differences between lunar lava tubes and earth one on geology and landform environments. Exo-genetics activities, such as meteorites, radiation, and sudden temperature bigger affect than Endo-genetic activities, such as effusion and earthquake of the lunar lava tubes. Landform and internal configuration of the lunar lava tubes due to the huge cave perilous landform that gravity difference have a technical limitation from internal approach and data obtain of the huge skylights and sinuous rilles. Stability of the lunar lava tubes deals with geology and landform. It was obvious geo-structural stability elements results generated on low rate of collapsed halls(skylights), low gravity, and relatively thick covers. In terms of the communication capability on the external and internal lunar lava tubes cordless communication techniques will overcome limitations of the sun-power generates supporting communication systems. Through this research it realized obvious differs between potential habitats possibility by accumulative theories by scholars and techniques of the lunar lava tubes. Especially, it is a favorable expectation throughout overcoming attempt on zero gravity, cosmo radiation, lunar dust of the exo-genetic limitations to the steep escarpment of skylights to approach and achieve techniques by the civil engineering, networking and GIS techniques as the endo-genetic environment treatment.

The effect of small embankments on wind speeds

  • Quinn, A.D.;Robertson, A.P.;Hoxey, R.P.;Short, J.L.;Burgess, L.R.;Smith, B.W.
    • Wind and Structures
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    • v.1 no.4
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    • pp.303-315
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    • 1998
  • Full-scale measurements have been made to determine the increase in wind speed over two exposed embankments, one of $23^{\circ}$ slope and 4.7 m in height, the other of $24^{\circ}$ slope and 7.3 m in height. Measurements were made at heights of 5, 10 and 15 m above the upper edge of each embankment and at the same heights approximately 100 m upwind in the lower-level approach fetch. Despite the modest sizes of the embankments, the maximum recorded increase in mean wind speed was 28% and the minimum was 13%; these increase relate to increases in wind loads on structures erected at the top of the embankments of 64% and 28% respectively. The associated increases in gust speeds are estimated at 33% and 18%, which imply increases in gust loading of 77% and 39% respectively. These experimental results are compared with predictions obtained from a computational fluid dynamics (CFD) analysis, using three high Reynolds number eddy-viscosity models and estimates from the UK wind loading code, BS 6399: Part 2. The CFD results are generally in agreement with the experimental data, although near-ground effects on the embankment crest are poorly reproduced.

The Clever Hare in Torobo Folklore

  • Ashdown, Shelley
    • Cross-Cultural Studies
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    • v.28
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    • pp.87-114
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    • 2012
  • The Maa speaking Torobo people inhabiting the southern portion of the Mau Escarpment in Kenya approach both individual and community survival from a relational orientation focused on ethnic identity and responsibility. This social responsibility to the tribe is in stark contrast to Torobo relationships with other ethnic groups. The purpose of the research is twofold. First, the paper explores how folkloric language through a trickster image reflects important cultural and social ideals, understandings, and patterns of thought in Torobo world view. A second purpose is to offer ethnographic information to scholars and students' alike necessary for world view studies of eastern Africa specifically focused on the interplay between anthropomorphic tales and the social context in which these stories are utilized. The key research question for this analysis asks how the trickster image in Torobo folklore conceptualize the life experience. A Torobo folktale entitled, The Clever Hare, is the text chosen for analysis with the hare character as the protagonist. A second query explores the importance of the trickster image in understanding Torobo world view categories of Self and Other. The analysis contributes an ethnographic perspective for the world view categories of Self and Other as well as trickster folklore by examining the nature of Torobo-ness using the tale of the cunning hare as a research tool.

The Development of Landslide Predictive System using Measurement Information based on u-IT (u-IT기반 계측정보를 이용한 급경사지붕괴 예측 시스템 개발)

  • Cheon, Dong-Jin;Park, Young-Jik;Lee, Seung-Ho;Kim, Jeong-Seop;Jung, Do-Young
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.14 no.10
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    • pp.5115-5122
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    • 2013
  • This paper has studied about the development and application of landslide collapse prediction real-time monitoring system based on USN to detect and measure the collapse of landslide. The rainfall measuring sensor, gap water pressure sensor, indicator displacement measuring sensor, index inclination sensor, water content sensor and image analysis sensor are selected and these are applied on the test bed. Each sensor's operation and performance for reliability verification is tested by the instrument which is installed in the field. As the result, u-IT based real-time landslide monitoring system which is developed by this research for landslide collapse detection could minimize life and property damages because it makes advance evacuation with collapse risk pre-estimate through real-time monitoring on roadside cut and bedrock slopes. This system is based on the results of this study demonstrate the effect escarpment plan are spread throughout.

Quaternary Geology of the Conjunction Area of the Yeongsan and Sampo rivers (영산강 하류와 삼포강 합류부 일대 제4기 지질 연구)

  • Kim, Ju-Yong;Yang, Dong-Yoon;Hong, Sei-Sun;Nahm, Wook-Hyun;Lee, Heon-Jong;Lee, Jin-Young;Kim, Jin-Kwan;Oh, Keun-Chang
    • The Korean Journal of Quaternary Research
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    • v.19 no.1
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    • pp.1-17
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    • 2005
  • This study aims to study the distribution and formation age of Quaternary deposits in the downstream of Yeongsan Estuarine River, encompassing Muan, Illo and Donggang counties. For this purpose the authors examine several borehole data, and step trench survey for excellent profiles was studied in connection with grain size population and magnetic susceptibility. As a result, it is interpreted that the coastal plain of the Yeongsan River was formed by sea level rise after Last Glacial Maximum(LGM). The fore edge/escarpment of coastal terraces distributed 7-10 m asl is assumed to be formed during the last glacial period, while the coastal terraces distributed above 7-10m asl formed during MIS 5a. In addition, the fore edge/escarpment of coastal terraces distributed above 15 m asl is presumed to be have been formed during the stadial of last interglacial period, while the formation age of coastal terraces distributed above 15m(asl) is assumed to be MIS 5e. This formation age can be estimated by the coastal terrace ages of the southeastern coast of Korean Peninsula. The characteristics of Quaternary deposits linked to paleolithic culture will eventually lead to the reconstruction of ecosystem environment of paleolithic peoples.

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Woody Plant Species Composition, Population Structure and Carbon Sequestration Potential of the A. senegal (L.) Willd Woodland Along a Distance Gradient in North-Western Tigray, Ethiopia

  • Birhane, Emiru;Gebreslassie, Hafte;Giday, Kidane;Teweldebirhan, Sarah;Hadgu, Kiros Meles
    • Journal of Forest and Environmental Science
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    • v.36 no.2
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    • pp.91-112
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    • 2020
  • In Ethiopia, dry land vegetation including the fairly intact lowland and western escarpment woodlands occupy the largest vegetation resource of the country. These forests play a central role in environmental regulation and socio-economic assets, yet they received less scientific attention than the moist forests. This study evaluated the woody plant species composition, population structure and carbon sequestration potential of the A. senegal woodland across three distance gradients from the settlements. A total of 45 sample quadrants were laid along a systematically established nine parallel transect lines to collect vegetation and soil data across distance gradients from settlement. Mature tree dry biomass with DBH>2.5 cm was estimated using allometric equations. A total of 41 woody plant species that belong to 20 families were recorded and A. senegal was the dominant species with 56.4 IVI value. Woody plant species diversity, density and richness were significantly higher in the distant plots compared to the nearest plots to settlement (p<0.05). The cumulative DBH class distribution of all individuals had showed an interrupted inverted J-shape population pattern. There were 19 species without seedlings, 15 species without saplings and 14 species without both seedlings and saplings. A significant above ground carbon (5.3 to 12.7 ton ha-1), root carbon (1.6 to 3.6 ton ha-1), soil organic carbon (35.6 to 44.5 ton ha-1), total carbon stock (42.5 to 60.7 ton ha-1) and total carbon dioxide equivalent (157.7 to 222.8 ton ha-1) was observed consistently with an increasing of distance from settlement (p<0.05). Distance from settlement had significant and positive correlation with species diversity and carbon stock at 0.64⁎⁎ and 0.78⁎⁎. Disturbance intensity may directly influence the variation of species composition, richness and density along the A. senegal woodland. The sustainability of the A. senegal woodland needs urgent protection, conservation and restoration.