• Title/Summary/Keyword: potential tsunamis

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Propagation Characteristics of Potential Tsunamis near Ryukyu Islands (유구열도 주변 잠재 지진해일 전파특성)

  • Bae, Jae-Seok;Choi, Jun-Woo;Yoon, Sung-Bum
    • 한국방재학회:학술대회논문집
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    • 2008.02a
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    • pp.451-454
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    • 2008
  • Potential tsunamis which may occur near Ryukyu Islands were simulated. Propagation characteristics of the potential tsunamis over the southwestern sea and the influence of tsunamis on the southwestern coast of Korean Peninsula were analyzed. The shallow water area in the east sea of China and the deep water Okinawa Trough play an important role in wave transformation and propagation of the potential tsunamis. The propagation characteristics of the potential tsunamis generated near Ryukyu Islands can be described as in followings : In the first stage after generation, the tsunamis propagate with high speed both northeastward and southwestward along the Okinawa Trough. As a result the waves are elongated and the tsunami height is significantly reduced. The elongated crest of tsunamis spans the whole distance of the Okinawa Trough and lines up toward the edge of the continental shelf of East China Sea. Then, the tsunamis are propagating towards the southeast coast of China. Thus, the influence of tsunamis on the Korean coasts becomes weak.

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The Influence of Tsunamis on Moored Ships and Ports

  • Kubo Masayoshi;Cho Ik-Soon;Sakakibara Shigeki;Kobayashi Eiichi;Koshimura Syunichi
    • Journal of Navigation and Port Research
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    • v.29 no.4
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    • pp.319-325
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    • 2005
  • Planning for the construction of ports and harbors usually takes place without the consideration of tsunamis because of their rare occurrence, approximately once every 100 years. However, recent warnings indicate that massive earthquakes could occur in Japan within the next 30 years. Earthquakes may generate large-scale tsunamis. Therefore, any tsunamis in the vicinity of Japan would also be expected to affect eastern Korea. Therefore, with the looming concerns of tsunamis and earthquakes, immediate attention must be given to the planning of ports and harbors. The warnings deserve an immediate response. The threatened regions cover a very large territory, and the degree of severity of the tsunamis is forecasted to be varied. Therefore, any modeling of the potential scenarios will require a broad array of possibilities. The objective of this paper is to consider the potential damage from tsunamis to ports and moored ships in Japan and Korea. In addition, consideration will be given to how the construction plans of ports and harbors should be changed to cope with the threats from earthquakes and tsunamis.

Propagation Characteristics of Potential Tsunamis in Okinawa Trough (오키나와 트러프 잠재 지진해일 전파특성)

  • Kim, Jong-Hak;Choi, Weon-Hack;Bae, Jae-Seok;Yoon, Sung-Bum
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.20 no.3
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    • pp.268-276
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    • 2008
  • Potential tsunamis generated in Okinawa Trough were simulated for the investigation of the propagation characteristics in the southwestern sea of Korean Peninsula. Shallow waters in the continental shelf of East China Sea and deep waters in Okinawa Trough play an important role in the propagation characteristics of the tsunamis generated in this region. The propagation characteristics can be classified into two phases according to the stage of propagation. In the first phase, the tsunamis propagate both northeast and southwest along the deep water of the trough. In the second phase, the tsunamis enter the continental shelf of the East China Sea at right angles to topographic contour lines. Simulated results show that the tsunamis generated in the Okinawa Trough give a weak influence to the southern and western coasts of Korea due to the special topography of the southwestern sea of Korean Peninsula.

STRATEGIC POSITIONING OF SEA LEVEL GAUGES FOR EARLY CONFIRMATION OF TSUNAMIS IN THE INTRA-AMERICAS SEA

  • Henson, Joshua I.;Muller-Karger, Frank;Wilson, Doug;Maul, George;Luther, Mark;Morey, Steve;Kranenburg, Christine
    • Proceedings of the KSRS Conference
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    • v.1
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    • pp.29-33
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    • 2006
  • The potential impact of past Caribbean tsunamis generated by earthquakes and/or massive submarine slides/slumps, as well as the tsunamigenic potential and population distribution within the Intra-Americas Sea (IAS) was examined to help define the optimal location for coastal sea level gauges intended to serve as elements of a regional tsunami warning system. The goal of this study was to identify the minimum number of sea level gauge locations to aid in tsunami detection and provide the most warning time to the largest number of people. We identified 12 initial, prioritized locations for coastal sea level gauge installation. Our study area approximately encompasses $7^{\circ}N$, $59^{\circ}W$ to $36^{\circ}N$, $98^{\circ}$ W. The results of this systematic approach to assess priority locations for coastal sea level gauges will assist in developing a tsunami warning system (TWS) for the IAS by the National Oceanic and Atmospheric Administration (NOAA) and the Intergovernmental Oceanographic Commission's Regional Sub-Commission for the Caribbean and Adjacent Regions (IOCARIBE-GOOS).

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Prediction of Coastal Inundation due to Tsunamis : Pohang New Port (지진해일에 의한 해수범람 예측 : 포항신항)

  • Sim, Ju-Yeol;Ha, Tae-Min;Cho, Yong-Sik
    • Journal of the Korean Society of Hazard Mitigation
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    • v.8 no.4
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    • pp.135-143
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    • 2008
  • During the last decades several devastating tsunamis have been occurred. Recently, there have been increasingly concerned about tsunamis around the Korean Peninsula since the 2004 Sumatra Tsunami occurred on December 26, 2004. In general, the Korean Peninsula is not safe against potential tsunami attacks. The 1983 Central East Sea Tsunami and the 1993 Hokkaido Tsunami caused considerable damage to the Eastern Part of the Peninsula. Thus, a prediction of damage due to tsunamis must be required at the Eastern Part of the Peninsula. In this study, numerical simulation of tsunamis at Pohang New Port, one of the most important ports in the Eastern Part of Korea, is conducted for three different tsunami events. Numerical simulation is focused on inundation on the port and run-down around an intake structure which supplies cooling water to the porthinterland. The computed results show that Pohang New Port is damaged by the most dangerous tsunami which can be generated in the East Sea. Thus, it is required to set up a counter-measure against tsunami attacks at Pohang New Port.

APPLICATION OF HF COASTAL OCEAN RADAR TO TSUNAMI OBSERVATIONS

  • Heron, Mal;Prytz, Arnstein;Heron, Scott;Helzel, Thomas;Schlick, Thomas;Greenslade, Diana;Schulz, Eric
    • Proceedings of the KSRS Conference
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    • v.1
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    • pp.34-37
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    • 2006
  • When tsunami waves propagate across open ocean they are steered by Coriolis force and refraction due to gentle gradients in the bathymetry on scales longer than the wavelength. When the wave encounters steep gradients at the edges of continental shelves and at the coast, the wave becomes non-linear and conservation of momentum produces squirts of surface current at the head of submerged canyons and in coastal bays. HF coastal ocean radar is well-conditioned to observe the current bursts at the edge of the continental shelf and give a warning of 40 minutes to 2 hours when the shelf is 50-200km wide. The period of tsunami waves is invariant over changes in bathymetry and is in the range 2-30 minutes. Wavelengths for tsunamis (in 500-3000 m depth) are in the range 8.5 to over 200 km and on a shelf where the depth is about 50 m (as in the Great Barrier Reef) the wavelengths are in the range 2.5 - 30 km. It is shown that the phased array HF ocean surface radar being deployed in the Great Barrier Reef (GBR) and operating in a routine way for mapping surface currents, can resolve surface current squirts from tsunamis in the wave period range 20-30 minutes and in the wavelength range greater than about 6 km. There is a trade-off between resolution of surface current speed and time resolution. If the radar is actively managed with automatic intervention during a tsunami alert period (triggered from the global seismic network) then it is estimated that the time resolution of the GBR radar may be reduced to about 2 minutes, which corresponds to a capability to detect tsunamis at the shelf edge in the period range 5-30 minutes. It is estimated that the lower limit of squirt velocity detection at the shelf edge would correspond to a tsunami with water elevation of less than 5 cm in the open ocean. This means that the GBR HF radar is well-conditioned for use as a monitor of small and medium scale tsunamis, and has the potential to contribute to the understanding of tsunami genesis research.

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A Study of the Optimal Deployment of Tsunami Observation Instruments in Korea (지진해일 조기탐지를 위한 한국의 지진해일 관측장비 최적 위치 제안 연구)

  • Lee, Eunju;Jung, Taehwa;Kim, Ji-Chang;Shin, Sungwon
    • Journal of Ocean Engineering and Technology
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    • v.33 no.6
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    • pp.607-614
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    • 2019
  • It has been an issue among researchers that the tsunamis that occurred on the west coast of Japan in 1983 and 1993 damaged the coastal cities on the east coast of Korea. In order to predict and reduce the damage to the Korean Peninsula effectively, it is necessary to install offshore tsunami observation instruments as part of the system for the early detection of tsunamis. The purpose of this study is to recommend the optimal deployment of tsunami observation instruments in terms of the higher probability of tsunami detection with the minimum equipment and the maximum evacuation and warning time according to the current situation in Korea. In order to propose the optimal location of the tsunami observation equipment, this study will analyze the tsunami propagation phenomena on the east sea by considering the potential tsunami scenario on the west coast of Japan through numerical modeling using the COrnell Multi-grid COupled Tsunami (COMCOT) model. Based on the results of the numerical model, this study suggested the optimal deployment of Korea's offshore tsunami observation instruments on the northeast side of Ulleung Island.

Analysis of Tsunami Characteristics of Korea Southern Coast Using a Hypothetical Scenario (가상시나리오에 따른 남해안 지진해일 특성 연구)

  • Bumshick Shin;Dong-Seog Kim;Dong-Hwan Kim;Sang-Yeop Lee;Si-Bum Jo
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.36 no.2
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    • pp.80-86
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    • 2024
  • Large-scale earthquakes are occurring globally, especially in the South Asian crust, which is experiencing a state of tension in the aftermath of the 2011 East Japan Earthquake. Uncertainty and fear regarding the possibility of further seismic activity in the near future have been on the rise in the region. The National Disaster Management Research Institute has previously studied and analyzed the overflow characteristics of a tsunami and the rate of flood forecasting through tsunami numerical simulations of the East Sea of South Korea. However, there is currently a significant lack of research on the Southern Coast tsunamis compared to the East Coast. On the Southern Coast, the tidal difference is between 1~4 m, and the impact of the tides is hard to ignore. Therefore, it is necessary to analyze the impact of the tide propagation characteristics on the tsunami. Occurrence regions that may cradle tsunamis that affect the southern coast region are the Ryukyu Island and Nankai Trough, which are active seafloor fault zones. The Southern Coast has not experienced direct damage from tsunamis before, but since the possibility is always present, further research is required to prepare precautionary measures in the face of a potential event. Therefore, this study numerically simulated a hypothetical tsunami scenario that could impact the southern coast of South Korea. In addition, the tidal wave propagation characteristics that emerge at the shore due to tide and tsunami interactions will be analyzed. This study will be used to prepare for tsunamis that might occur on the southern coast through tsunami hazard and risk analysis.

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.