216 research outputs found

    Effects of Harbor Shape on the Induced Sedimentation; L-Type Basin

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    Tsunamis in shallow water zones lead to sea water level rise and fall, strong currents, forces (drag, impact, uplift, etc.), morphological changes (erosion, deposition), dynamic water pressure, as well as resonant oscillations. As a result, ground materials under the tsunami motion move, and scour/erosion/deposition patterns can be observed in the region. Ports and harbors as enclosed basins are the main examples of coastal structures that usually encounter natural hazards with small or huge damaging scales. Morphological changes are one of the important phenomena in the basins under short and long wave attack. Tsunamis as long waves lead to sedimentation in the basins, and therefore, in this study, the relation to the current pattern is noticed to determine sedimentation modes. Accordingly, we present a methodology based on the computation of the instantaneous Rouse number to investigate the tsunami motion and to calculate the respective sedimentation. This study aims to investigate the effects of the incident wave period on an L-type harbor sedimentation with a flat bathymetry using a numerical tool, NAMI DANCE, which solves non-linear shallow water equations. The results showed that the corner points on the bending part of the basin are always the critical points where water surface elevation and current velocity amplify in the exterior and interior corners, respectively

    Lessons Learned from the 2011 Great East Japan Tsunami: Performance of Tsunami Countermeasures, Coastal Buildings, and Tsunami Evacuation in Japan

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    In 2011, Japan was hit by a tsunami that was generated by the greatest earthquake in its history. The first tsunami warning was announced 3 min after the earthquake, as is normal, but failed to estimate the actual tsunami height. Most of the structural countermeasures were not designed for the huge tsunami that was generated by the magnitude M = 9.0 earthquake; as a result, many were destroyed and did not stop the tsunami. These structures included breakwaters, seawalls, water gates, and control forests. In this paper we discuss the performance of these countermeasures, and the mechanisms by which they were damaged; we also discuss damage to residential houses, commercial and public buildings, and evacuation buildings. Some topics regarding tsunami awareness and mitigation are discussed. The failures of structural defenses are a reminder that structural (hard) measures alone were not sufficient to protect people and buildings from a major disaster such as this. These defenses might be able to reduce the impact but should be designed so that they can survive even if the tsunami flows over them. Coastal residents should also understand the function and limit of the hard measures. For this purpose, non-structural (soft) measures, for example experience and awareness, are very important for promoting rapid evacuation in the event of a tsunami. An adequate communication system for tsunami warning messages and more evacuation shelters with evacuation routes in good condition might support a safe evacuation process. The combination of both hard and soft measures is very important for reducing the loss caused by a major tsunami. This tsunami has taught us that natural disasters can occur repeatedly and that their scale is sometimes larger than expected

    THE 25 MARCH 2020 TSUNAMI AT THE KURIL ISLANDS: ANALYSIS AND NUMERICAL SIMULATION

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    A strong earthquake with a magnitude of 7.5 occurred near the island of Paramushir (KurilIslands) on 25 March 2020. It caused a weak tsunami in Kamchatka and the Kuril Islands.Earthquake and tsunami data from three DART buoys are discussed and compared withnumerical simulations. It is shown that the calculated and measured tsunami characteristics onthe DART buoys is in very good agreement. There are also data on the recording of thisearthquake by a laser strain-meter installed in the Sea of Japan at Shults cape at a distance ofmore than 2,000 km from the epicenter of the earthquake. There is also an instrumentalrecording of the tsunami at the Vodopadnaya point in the southeast of Kamchatka.Unfortunately, there was a large storm at sea at this time, and the amplitudes of tsunami wavesand storm waves were comparable to each other, so here the agreement between calculationsand observations does not seem good enough

    Discovery of Minoan tsunami deposits

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    The Hellenic are is a terrane of extensive Quaternary volcanism. One of the main centers of explosive eruptions is located on Thera (Santorini), and the eruption of the Thera volcano in late Minoan time (1600-1300 B.C.) is considered to have been the most significant Aegean explosive volcanism during the late Holocene. The last eruptive phase of Thera resulted in an enormous submarine caldera, which is believed to have produced tsunamis on a large scale. Evidence suggesting seawater inundation was found previously at some archaeological sites on the coast of Crete; however, the cause of the tsunami and its effects on the area have not been well understood. On the Aegean Sea coast of western Turkey (Didim and Fethye) and Crete (Gouves), we have found traces of tsunami deposits related to the Thera eruption. The sedimentological consequences and the hydraulics of a Thera-caused tsunami indicate that the eruption of Thera volcano was earlier than the previous estimates and the tsunami did not have disruptive influence on Minoan civilization

    Deniz Koruma Alanları Uydu Görüntü Destekli Kirlenme İzleme Ve Taşıma Kapasitesi Araştırma Projesi

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    Deniz turizminin yoğun olduğu bölgelerde deniz araçları kullanımı yoğun olmakta ve kirlenme boyutları limitleri aşmaktadır. Bunun önlenmesi için koylarda yat taşıma kapasitesinin ulaşabileceği sınır değerlerinin ortaya çıkarılması ve sağlıklı uygulanabilir önlemler geliştirilmesi önemlidir. Bu çalışma ile, Fethiye-Göcek Özel Çevre Koruma Bölgesi Göcek Körfezi ile koylarında, deniz üstü araçları açısından taşıma kapasitesinin belirlenmesi ve alan yönetimine ilişkin kararların alınabilmesi için bilimsel çalışma yapılarak, gerekli veri tabanı oluşturulması ve izleme amaçlı bilgisayar yazılım araçları geliştirilmesi ve öneriler hazırlanması amaçlanmıştır. Önerilen Araştırma Projesi, Fethiye Koyu' nda su çevrimi ve kirlenme özelliklerinin yıllık değişimlerini Coğrafi Bilgi Sistemi tabanlı veriler kullanıp analiz ederek, yerinde ölçümlerle doğrulayıp, yat hareketlerini izlemeyi ve bu verileri kullanarak körfezin yat taşıma kapasitesini saptamayı amaçlamaktadır. Proje kapsamında yüksek çözünürlüklü uydu görüntüleri elde edilmesi, bu görüntülerin yeni gelişmiş özel amaçlı yazılımlar kullanarak analiz edilerek kirletici parametrelerinin çıkarılması, bu parametrelerin saha değerlerinin yerinde ölçümler yapılarak kalibrasyon yapılması, su parametrelerinin ölçümlerle izlenmesi, yat hareketlerinin kamera ile izlenmesi, yatlardan ve karadan gelen kirleticilerin araştırılması ve kirlenme potansiyelinin bulunması ve kıyı Alanları Yönetim planı içinde Özel Çevre Koruma Bölgeleri için Taşıma Kapasitesi hesaplanması için yöntemler geliştirilmesi ve Fethiye Körfezi Yat taşıma kapasitesi saptanması sağlanacaktır

    Transmission and reflection of solitary waves from vertical porous structures

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    Ph.D. - Doctoral Progra

    Tsunami risk and strategies for the European region (TRANSFER)

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    The project main goal is to contribute to our understanding of tsunami processes in the Euro-Mediterranean region, to the tsunami hazard and risk assessment and to identifying the best strategies for reduction of tsunami risk. Focus will be posed on the gaps and needs for the implementation of an efficient tsunami early warning system (TEWS) in the Euro-Mediterranean area, which is a high-priority task in consideration that no tsunami early warning system is today in place in the Euro-Mediterranean countries. The main items addressed by the project may be summarised as follows. The present Europe tsunami catalogue will be improved and updated, and integrated into a worldwide catalogue (WP1). A systematic attempt will be made to identify and to characterise the tsunamigenic seismic (WP2) and non-seismic (WP3) sources throughout the Euro-Mediterranean region. An analysis of the present-day earth observing and monitoring (seismic, geodetic and marine) systems and data processing methods will be carried out in order to identify possible adjustments required for the development of a TEWS, with focus on new algorithms suited for real-time detection of tsunami sources and tsunamis (WP4). The numerical models currently used for tsunami simulations will be improved mainly to better handle the generation process and the tsunami impact at the coast (WP5). The project Consortium has selected ten test areas in different countries. Here innovative probabilistic and statistical approaches for tsunami hazard assessment (WP6), up-to-date and new methods to compute inundation maps (WP7) will be applied. Here tsunami scenario approaches will be envisaged; vulnerability and risk will be assessed; prevention and mitigation measures will be defined also by the advise of end users that are organised in an End User Group (WP8). Dissemination of data, techniques and products will be a priority of the project (WP9).STREP - Specific Targeted Research Project (FP6-2005-GLOBAL-4
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