This study is assessing the tsunami hazard for a segment of the Kamchatka western coast around the Oktyabrsky Spit. The motivation is to ensure transportation access to the village of Oktyabrsky and to the fish processing facilities situated on the Spit. The hazard estimates were derived by the worst case method. An analysis of seismicity and historical data on tsunami occurrences in the Sea of Okhotsk resulted in identification of two tsunami-generating zones that constitute threat to the Oktyabrsky coast segment, with a set of model tsunami-generating earthquakes being determined for each zone. For this set of models we conducted numerical modeling for tsunami generation and propagation, resulting in a selection of model sources that would pose the greatest threat to the coastal strip of interest. The next step involved refining calculations for these sources using a sequence of nested grids to find the parameters of tsunami impact on the coast. The main results of the present study consist in identification of tsunami-generating zones that pose the highest threat to the Oktyabrsky coast, the selection of tsunami-generating model sources in these zones, and estimates of parameters that characterize extreme tsunami waves posing threat to this coast strip.

This paper describes a numerical simulation within the framework of a two-dimensional shallow water model of interaction of a solitary wave with a steady rectangular semi-submerged structure. The results of this study are compared with the results of calculations based on a model of irrotational three-dimensional flows, and it is shown that the simulation accuracy at small incident wave amplitudes is satisfactory. It is also revealed that, the solitary wave diffraction on the cylinder surface is neglected when using a one-dimensional shallow water model, then the maximum values of wave runup on the edge of the cylinder and the force loads on it become overestimated.

This paper describes the results from a numerical simulation of long surface waves interaction with fixed and partially immersed structure located over irregular bottom. The topic is connected with risk of critical wave impact on structures placed in the coastal waters of seas and oceans. The wave–structure interaction is simulated within the framework of a hierarchy of mathematical models, including the model of potential flows of an ideal fluid, a fully nonlinear dispersive and dispersionless shallow water models. The numerical algorithm for the dispersive model is described in detail. The obtained results show that rectangular cutout in the structure bottom reduces the amplitude of the reflected wave and increases that of the transmitted one; the basin bottom irregularity plays the most important role when located directly under the body. The protrusion behind the body may slightly decrease the wave force, and it significantly increases the force at other locations. Generally, the results obtained by the dispersive model correspond well with those of potential model, while the dispersionless model often significantly overestimates the wave force and amplitude of the reflected wave.

The problem of the interaction of a solitary wave with a partially immersed fixed body over an irregular bottom is considered. This problem is solved using the nonlinear dispersive shallow-water (Serre–Green–Naghdi) model and the potential flow model. The influence of the horizontal and vertical sizes of bottom irregularities and their location relative to the partially immersed body on the values of the total force acting on the body is studied numerically. It is shown that the horizontal component of this force increases monotonically with increasing vertical dimension and length of the underwater obstacle. This effect is enhanced when approaching the body. The vertical component of the force is slightly affected by the obstacle, and its dependence on the obstacle size may be nonmonotonic.

This paper describes the numerical simulation of the solitary wave impact on a partially immersed and fixed structure located over a flat coastal slope. This topic is related to the need for assessment of the possible impact of long waves, such as tsunamis, on partially immersed structures in coastal waters. Numerical algorithms on a movable grid adapting to the motion of the shore point are developed for a fully nonlinear dispersive model and a dispersionless shallow water model. Their validation is carried out by comparing the obtained solutions with the data from laboratory experiments and with the results obtained using a fully nonlinear potential flow model. The study shows that the difference between the maximum wave impact on the body at the foot of the slope and near the shore can be up to 6 times. In many cases, the maximum horizontal component of the wave force occurs under the influence of the wave reflected from the shore, indicating the need to consider the influence of the shore-reflected wave when assessing the impact of long waves on structures located in coastal waters. Furthermore, the need to use runup algorithms instead of reflective boundary conditions (vertical wall) has been identified for gentler slopes, where the differences in the wave impact for these two configurations can be 2–3 times.

В настоящее время некоторые высокотехнологичные конструкции размещаются в акваториях морей и океанов. Это обстоятельство обуславливает значительный риск критического волнового воздействия на эти конструкции во время их создания и эксплуатации, вызванного, в частности волнами цунами. В перечень такого рода конструкций входят хранилища сжиженного природного газа, плавучие атомные, волновые и приливные электростанции, причальные и волнозащитные сооружения, нефте-газодобывающие платформы в виде плавучих (заякоренных) полупогруженных тел в прибрежных зонах. Конструирование, размещение и эксплуатация таких объектов в цунамиопасных зонах требует оценок силового воздействия цунами на эти объекты. Расчёт воздействия этих длинных волн на конструкцию, в частности, позволяет рассчитать необходимую массу (расположение) якорей, предохраняющих конструкцию от недопустимых перемещений, способных привести к катастрофическим последствиям от выброса на берег и столкновения с другими объектами

Currently, the most popular approach for assessing the tsunami hazard on a coast is the PTHA (Probabilistic Tsunami Hazard Assessment). In this preliminary study, we develop one of the variants of the SPTHA (Seismic PTHA) method, adapted to solving local tsunami zonation problems for near-field sources. The approach is applied to assessing the tsunami hazard of the Bechevinskaya Cove located on the eastern coast of the Kamchatka Peninsula in the northern part of Avachinsky Bay. We propose the method, algorithms and results of probabilistic assessment of the cove's tsunami hazard in order to determine the safest water areas, in which the values of the intensity measures (IMs) of tsunami will not exceed the specified threshold values with the given Average Return Periods (ARPs). The method includes analysis of seismotectonics of the region, construction of a catalog of model tsunamigenic earthquakes, determination of their statistical characteristics, scenario numerical modeling of the dynamics of tsunami waves, calculations of the values of IMs that can be exceeded with the given annual rates (ARs), namely, on average 1 time in 100, 500, 1000 years. Spatial distributions of the maximum wave heights and maximum velocities are provided for the ARs. Three configurations of the water area are considered, including the possibility of constructing protective structures, and conclusions are drawn about their influence on the tsunami hazard assessments in the cove.

This paper describes the results from a numerical estimation of the force exerted by long surface waves on a fixed and partially immersed rectangular structure. The topic is connected with the need of making decisions on the design, placement and operation of hydrotechnical structures of this kind. The wave-structure interaction is simulated in the framework of a nonlinear potential flow model. The results obtained allow to determine the dependence of the hydrodynamic force on the length and amplitude of a single wave, the length and submergence of the structure. We compare the results obtained for different initial wave shapes, and consider the differences between the forces acting on a vertical wall and a partially immersed structure. In particular, it is shown that at relatively small submergence of the structure, longer waves affect it less, while at large submergence and in the case of wave-wall interaction, the opposite behaviour is observed.

Abstract We investigate the ability of a submarine landslide to generate the tsunami waves observed on the Bulgarian coast of Black Sea on 7 May 2007. In our simulations, a landslide is presented as a quasi-deformable body moving along a curvilinear slope under action of the forces of gravity, buoyancy, water resistance and bottom friction. We employ the fully non-linear weakly dispersive model for tsunami wave simulations. The computations show that the initial landslide position on the real slope is extremely important for its dynamics and the wave generation process. We constructed some model landslides which generated similar waves to those observed. Moreover, these landslides stopped in the same region. Finally, we evaluated the significance of the frequency dispersion effects in the simulations.

Созданы обзорные карты цунамиопасности Дальневосточного побережья России. Обсуждаются методологические основы подхода, основанного на методике РТНА (Probabilistic Tsunami Hazard Assessment), а также проблемы построения сейсмотектонических моделей основных цунамигенных зон, численные методики получения расчётных каталогов высот волн на побережье и некоторые проблемы применения методики РТНА, связанные как с недостаточностью данных наблюдений, так и со сложностью выполнения большого объёма сценарного численного моделирования. Приведены примеры обзорных карт цунамиопасности для различных повторяемостей, представленные в приложении WTMap.

В работе идет речь о реализации методики вероятностного цунамирайонирования побережья, известной под названием PTHA (Probabilistic Tsunami Hazard Assessment), для создания обзорных карт цунамиопасности дальневосточного побережья России. Обсуждаются методологические основы такого подхода, проблемы построения сейсмотектонических моделей основных цунамигенных зон, численные методики получения расчетных каталогов высот волн на побережье. Приведены примеры обзорных карт для различных повторяемостей, построенных с применением методики PTHA и представленных с помощью созданного веб-приложения WTMap. Упоминаются также некоторые проблемы применения методики PTHA, связанные как с недостаточностью данных наблюдений, так и со сложностью выполнения большого объема сценарного численного моделирования.The article describes the results of the implementation of the PTHA (Probabilistic Tsunami Hazard Assessment) methodology for creating the overview maps of tsunami hazard for the Far East coast of the Russian Federation. Such maps show the characteristics of the catastrophic impact of tsunami waves on the coast and the probability of their exceeding in a given period of time. The methodological basis of the PTHA approach to the assessment of tsunami hazard, the problems of constructing seismotectonic models of the main tsunamigenic zones, mathematical models and algorithms for calculating probability estimates of tsunami danger are discussed. The version of the PTHA methodology outlined in the article is implemented as a “WTmap” Web-application that has an access to the entire observational information related to coastal tsunami zoning and software packages used. The application allows to obtain the estimates of the expected tsunami heights and their recurrence estimates and to map them on specific parts of the Far Eastern coast of the Russian Federation. The obtained estimates can be quickly recalculated when replacing the observational catalogs with more complete and reliable ones, with the addition of new, previously absent events or the revision of their parameters, as well as the results of new scenario calculations. Examples of overview maps for various recurrence intervals, constructed using the PTHA methodology and presented using the “WTMap” application, are given. Some problems of using the PTHA methodology related to the lack of available observational data and to the complexity of performing a large amount of scenario simulations are also discussed.

We present some approaches to solving a problem of shallow water oscillations in a parabolic basin (including an extra case of a horizontal plane). Some requirements on the form of the solutions and effects of Earth's rotation and bottom friction are made. The resulting solutions are obtained by solving ODE systems. The corresponding free surfaces are first- or second-order ones. Some conditions of finiteness and localization of the flow are analyzed. The solutions are used to verify the numerical algorithm of the large-particle method. The efficiency of the method is discussed in tests on wave run-up on shore structures.

Overview maps of tsunami hazards for the Far Eastern coast of the Russian Federation are created. The methodological principles of the PTHA (Probabilistic Tsunami Hazard Assessment) approach are discussed, as are the problems of constructing seismotectonic models of the main tsunamigenic zones, mathematical models and algorithms for calculating probability estimates of tsunami hazards, and some problems of applying the PTHA methods related both to the lack of observation data and the complexity in performing a large volume of numerical scenario simulations. Examples of overview maps of tsunami hazards for various recurrence intervals, constructed using the PTHA methodology and presented using the “WTMap” application, are given.

In the present paper we study features and abilities of the combined TVD+SPH method relative to problems of numerical simulation of long waves runup on a shore within the shallow water theory. The results obtained by this method are compared to analytic solutions and to the data of laboratory experiments. Examples of successful application of the TVD+SPH method are presented for the case of study of runup processes for weakly nonlinear and strongly nonlinear waves, and also for N-waves.

The numerical simulation of the run-up of long surface waves on a plane slope is presented.Using a method based on the combination of the TVD scheme and the SPH method the shallow water approximation is applied to the solution of the well known model problem of a run-up of a wave approaching from an area of constant depth towards a plane slope.The numerical method has proved to be reliable and effective not only in the range of small amplitudes, but also outside of the theoretical limits of applicability of the shallow water theory, such as for the modelling of breaking waves.The qualitative and partially quantitative comparison with the results of numerical calculations of other authors are presented.The differences in the results caused by the differences in the numerical algorithms are highlighted.

An approach to the computer simulation of a tsunami run-up on the coast is presented, based on nested grids and the large-particle method. The computational algorithms are based on the classical equations of shallow-water theory. The main elements of the developed computational technology are described and the results are given of the verification and validation of numerical algorithms, as well as the mathematical model and of one- and two-dimensional test problems. The capabilities of the algorithms developed by the authors are demonstrated for the calculation of the defining parameters of the tsunami run-up on the coast in the vicinity of the town of Severo-Kurilsk (November 5, 1952).

Цунамиопасность побережья Охотского моря требует тщательного анализа ввиду планируемого включения этой акватории в число зон ответственности Службы предупреждения о цунами, действующей на Дальневосточном побережье РФ. Не имея в своих пределах сейсмогенных зон, способных порождать опасные цунами, Охотское море тем не менее открыто для проникновения волн цунами, порождаемых источниками в других цунамигенных зонах Курило-Камчатского региона, а также всего Тихого океана. Проблема цунамиопасности побережья Охотского моря рассматривается в работе на основе материалов анализа исторических наблюдений и результатов численного моделирования распространения цунами от модельных очагов близких и удаленных землетрясений. Показано, что среди региональных землетрясений реальную угрозу цунами создают только очаги подводных землетрясений с магнитудой 8.5 и выше, расположенные в Курило-Камчатской сейсмогенной зоне. Среди удаленных цунамигенных зон Тихого океана наиболее опасны очаги мега-землетрясений класса М9 из южно-американской зоны и из зоны Папуа-Новая Гвинея, способные вызвать колебания с размахом до 5 м по всему побережью Охотского моря.

The tsunami hazard for the coast of the Sea of Okhotsk requires a careful analysis, because this sea will be a zone of responsibility for the Tsunami Warning Service for the Far East coast of Russia. While it is not subject to such hazards on the part of seismogenic zones that can produce dangerous tsunamis, nevertheless the Sea of Okhotsk is open for penetration of tsunamis that can be produced by sources in other tsunamigenerating zones of the Kuril–Kamchatka region, as well as those of the entire Pacific Ocean. The tsunami hazard for the coast of the Sea of Okhotsk is examined here on the basis of historical observations and the results of numerical simulation for tsunami propagation from hypothetical rupture zones of near and distant earthquakes. It is shown that the real tsunami hazard can only emanate from those regional earthquakes with magnitudes 8.5 or greater that occur in the Kuril–Kamchatka seismogenic zone. Among the remote tsunamigenerating zones in the Pacific, the most dangerous locations are the rupture zones of mega-earthquakes of the class M9 that come from the South America zone and from Papua–New Guinea. These can produce water waves with amplitudes as great as 5 m along the entire coast of the Sea of Okhotsk.