• Title/Summary/Keyword: tsunamis

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Estimation of Wave Pressure on Vertical Breakwaters due to Tsunamis (직립 방파제에 작용하는 지진해일 파압산정)

  • Hong, Seong-Soo;Ha, Tae-Min;Cho, Yong-Sik
    • 한국방재학회:학술대회논문집
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    • 2010.02a
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    • pp.64.1-64.1
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    • 2010
  • 국내 지진해일에 관한 연구 중, 구조물에 직접적인 영향을 미치는 파력에 대한 연구가 현재 미미한 실정이다. 본 연구에서는 파고와 입사각, 그리고 유의주기를 기지값으로 하여 파압을 계산하는 Goda(1974)가 제안한 파압공식을 이용하여 파압을 산정하였다. 파고는 Cho(1995) 모델로 산정하였으며 이를 임원항구의 방파제에 적용하였다.

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Characteristics of Tsunamis and Mitigation Planning (지진해일의 특성 및 방재대책)

  • Cho, Yong-Sik;Ha, Tae-Min
    • Geophysics and Geophysical Exploration
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    • v.13 no.3
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    • pp.295-300
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    • 2010
  • Recently, many tsunamis triggered by impulsive undersea ground motions occurred in subduction zones around the Pacific Ocean area including the East Sea surrounded by Korea, Japan and Russia. The wave height of a tsunami may be in the order of several meters, while the wavelength can be up to 1,000 km in the ocean, where the average water depth is about 4 km. A tsunami could cause a severe coastal flooding and property damage not only at neighboring countries but also at distant countries. A fundamental and economic way to mitigate unusual tsunami attacks is to construct tsunami hazard maps along coastal areas vulnerable to tsunami flooding. These maps should be developed based on the historical tsunami events and projected scenarios. The map could be used to make evacuation plans in the event of a real tsunami assault.

A Study on Dynamic Analysis of Moored Ship Motions by Tsunami (쓰나미에 의한 계류 선박의 동적 동요 해석에 관한 연구)

  • Cho Ik-Soon
    • Journal of Navigation and Port Research
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    • v.29 no.8 s.104
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    • pp.661-666
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    • 2005
  • Recent warnings indicate that there is a potential risk of massive earthquake. These earthquakes could produce large-scale tsunamis. Consideration of the effect of Tsunami to the moored ship is very important bemuse it brings the loss of life and vast property damage in a viewpoint of ship operations within a harbor. If a tsunami occurs, a ship in a harbor may begin drifting in case of ship entering and departing harbor, and breakage of mooring rope and drifting of moored ship are happened. And extremely serious accident, such as stranding and collision to a quay, might occur. On the other hand, since the tsunami consists of approximately component waves of several minutes, there is a possibility of resonance with the long period motion of mooring vessel. As the speed of Tsunami is much faster than tidal current in a harbor, a strong resisting force might act on the moored ships. In this paper, the numerical simulation procedure in the matter of ship motions due to the attack of large-scale tsunamis are investigated and the effects on the ship motions and mooring loads are evaluated by numerical simulation.

A Safety Evaluation of Moored Ship Motions by Observed Tsunami Profile

  • Cho, Ik-Soon;Kubo, Masayoshi;Kong, Gil-Young;Lee, Yun-Sok;Lee, Choong-Ro
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • v.1
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    • pp.47-52
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    • 2006
  • Recent warnings indicate that there is a potential risk of massive earthquake in Japan within 30 years. These earthquakes could produce large-scale tsunamis. Tsunamis are very powerful and can be traveled thousands of miles and caused damage in many countries. Consideration of the effect of tsunami to the moored ship is very important because it brings the loss of life and vast property damage. In this paper, the numerical simulation procedure to analyze the motions of a moored ship due to the observed waves of tsunami, Tokachi-off earthquake tsunami profile in northern Pacific coasts of Japan on September 26 in 2003. And the effects on the motions and mooring loads are investigated by numerical simulation. Numerical simulations consist of hydrodynamic analyses in a frequency domain and ship motion analyses in a time domain as the motions of moored ships are examined. As the process begins, the hydrodynamic and waveexciting forces for moored ships must be calculated. Ship motions and mooring forces can then be calculated by solving the equations of motion. In order to investigate the safety evaluation on the motions of moored ship by tsunami attack, we applied a numerical simulation procedure to a 135,000m3 LNG carrier moored at an offshore sea berth.

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Gas Hydrate (가스 하이드레이트)

  • Ryu Byong-Jae
    • 한국신재생에너지학회:학술대회논문집
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    • 2005.06a
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    • pp.609-614
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    • 2005
  • Gas hydrates are ice-l ike sol id compounds that are composed of water and natural gas. All common gas hydrates belong to the three crystal structures that are composed of five polyhedral cavities formed by hydrogen bonded water molecules and stable in specific high pressure and low temperature conditions. Gas hydrates contain large amounts of organic carbon and widely occur in deep oceans and permafrost regions, and they may therefore represent a potential energy resource in the future. United States and Japan perform the national R&D programs for the commercial production of gas hydrates in 2010's. The study on gas hydrates are also important for exploration and development of natural gas in the regions where gas hydrates are accumulated and could be formed. Although their global abundance is debated, they play an important role in global climate change since methane is a 50 times more effect ive greenhouse gas than carbon dioxide. Natural gas hydrates also form a possible natural hazard if rapidly dissociated and can cause slides and slumps and in the marine environment associated tsunamis.

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The Development of a Flood Protection System for Pad Transformers Using Pneumatic Pressure in Areas Prone to Floods

  • Kim, Gi-Hyun;Lee, Jae-Yong;Bae, Suk-Myong
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.24 no.3
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    • pp.27-32
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    • 2010
  • The inundation of substation and ground power equipment breaks out every summer season in low-lying downtown areas and low-lying shores by torrential rain, typhoons and tsunamis. It has, in turn, caused replacement, social and economic costs for blackouts. For activity management regarding flood damage we produced a flood protection system which using the Pad transformer as a basic frame and is developed using pneumatic pressure. We tested safety concerns including insulation resistance and current leakage first for water tank flooding and, second, by an empirical test through supplying 22.9[kV]. We estimate that costs associated with flooding and power failure can be diminished by these advances toward creating a more reliable system.

MANIFESTATIONS OF THE INDIAN OCEAN TSUNAMI OF 2004 IN SATELLITE NADIR-VIEWING RADAR BACKSCATTER VARIATIONS

  • Troitskaya, Yuliya I.;Ermakov, Stanislav A.
    • Proceedings of the KSRS Conference
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    • v.1
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    • pp.39-42
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    • 2006
  • The paper reports on the first experimental evidence for space-observed manifestation of the open ocean tsunami in the microwave radar backscatter (in C- and Ku-bands). Significant variations of the radar cross section synchronous with the sea level anomaly were found in the geophysical data record of the altimetry satellite Jason-1 for the track which crossed the head wave of the catastrophic tsunami of 26 December 2004. The simultaneous analysis of the available complementary data provided by the satellite three-channel radiometer enabled us to exclude meteorological factors as possible causes of the observed signal modulation. A possible physical mechanism of modulation of short wind waves due to transformation of the thin boundary layer in the air by a tsunami wave is discussed. The results open new possibilities of monitoring tsunamis from space..

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Traffic Control of Ad-hoc Network for Emergency Rescue Evacuation Support (긴급피난지원을 위한 애드혹 통신망에서 트래픽 제어)

  • Choi, Young-Bok
    • Journal of IKEEE
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    • v.22 no.2
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    • pp.375-383
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    • 2018
  • Recently, natural disasters including earthquakes, tsunamis, floods, and snowstorms, in addition to disasters of human origin such as arson, and acts of terror, have caused numerous injuries and fatalities around the world. We propose an area split clustering control method in multi-hop ah-hoc communication to reduce the amount of data traffic by allowing only parent terminals to exchange and share data for the emergency rescue and evacuation support system.

Estimation of Maximum Inundation Zone due to Tsunamis with Moving Boundary (이동경계를 이용한 지진해일의 최대범람구역 추산)

  • 조용식;서승원
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.13 no.2
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    • pp.100-108
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    • 2001
  • Along the shoreline a special treatment is required to simulate movement of periodic waves such as tsunami and tide because of continuous movement of shoreline as waves rise and recede. A moving boundary treatment is first proposed to track the movement of shoreline in this study. The treatment is then employed to obtain a maximum inundation area to be used for mitigation of coastal flooding. The obtained maximum inundation zone for a specific location is compared to that of available observed data. A reasonable agreement is observed.

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Numerical Simulations of 1983 Central East Sea Tsunami at Imwon: 1. Propagation across the East Sea (임원에서의 1983년 동해 중부 지진해일 수치모의: 1. 동해에서의 전파)

  • Cho, Yong-Sik;Lee, Ho-Jun
    • Journal of Korea Water Resources Association
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    • v.35 no.4 s.129
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    • pp.443-452
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    • 2002
  • The propagation of the 1983 Central East Sea Tsunami recorded as the most devastating tsunami during last decades across the East Sea is numerically simulated in this study h numerical model based on the shallow~water equations is employed. The physical dispersion is somewhat replaced by the numerical dispersion resulting from the leap-frog scheme. Traveling times of leading tsunamis are estimated and wane rays are calulated based on the Munk and Arthur(1952).