L. B. Chubarov

Simulation of surface waves generated by an underwater landslide moving over an uneven slope

Abstract This paper is focused on the study of the effect of an underwater slope unevenness on the wave mode characteristics caused by the motion of a landslide over this slope. Using the simplest model representation of a landslide in the form of a rigid body, the authors consider two model reliefs, taking to some extent into account the peculiarities of the Mediterranean coast of Israel. The simulation of wave processes is performed within the framework of the equations of the shallow water theory. The results of the comparison of wave modes are discussed, the dependences of the characteristics of these modes on geometric and physical parameters of the studied phenomena, such as the landslide bedding depth, its length and thickness, the geometry of the slope, and the friction force are analyzed.

Modelling surface waves generated by a moving landslide with allowance for vertical flow structure

In this paper we describe results obtained in numerical investigation of the mechanism of tsunami generation by a moving submerged landslide which is simulated by a solid body sliding down a slope. The authors perform complex multiparameter calculations by algorithms based on the hierarchy of wave hydrodynamics models comprising shallow water equations and full hydrodynamical equations of an ideal fluid. We investigate the crucial dependences of the wave formation process on the length and thickness of the landslide, its bedding depth, and the law of motion. A comparison of solutions obtained by the approximate and full models allowed us to assess the degree of impact of the vertical flow structure and specify the domain of applicability of the approximate models.

Using Numerical Modelling to Evaluate Tsunami Hazard Near the Kuril Island

A sequence of computer experiments is used to study questions concerning the tsunami problem as a quantitative estimate of tsunami danger, detailed geographical tsunami classification, determination of the parameters of ‘critical’ tsunami waves, and the conditions of their development. We call a wave ‘critical’, if its impact on the coast is most hazardous.Using the Middle Kuril Island as an example, we present the results of a computer experiment which includes determining the wavefields on the shelf and estimating the effects connected with the deep-water Bussol and Diana Straits.Numerical simulation of tsunami waves of different sources permits the assessment of the extent of tsunami danger in different areas of the coastal zone of Simushir Island, depending on the location of the focus zone and their geometry.The major singularities of the wavefield arise in the zones of the deep-water straits. The distribution of the amplification factors is determined by both the global parameters of the wavefields and the local properties of individual harbours. The results obtained for a particular harbour in the northern part of Simushir Island, formed the basis for the quantitative estimate of tsunami danger for this area.

Numerical simulation of the 1973 Shikotan (Nemuro-Oki) tsunami

Abstract The paper presents the results of numerical simulation of Shikotan (Nemuro-Oki) tsunami of 17 June 1973. Static deformations of the sea bottom are computed for some dimensional dislocation model of the seismic source with the parameters obtained from seismological observations. The computed bottom deformations are used as the initial conditions for the tsunami propagation problem in the ocean with a real bathymetry, which is considered within the framework of linear theory of shallow water. Three variants of tsunami source are examined. Travel time charts and computed mareograms at a number of points of the shoreline are presented. At 4 points, where tide-gauge records are available, the comparison of the computed mareograms with the observed ones is made. It is found that the numerical model can reproduce the basic features of the tsunami of 17 June 1973.

Numerical simulation of the action of distant tsunamis on the Russian Far East coast

Results of a numerical simulation of the action of distant tsunamis on the coast of the Russian Far East are presented. It is shown that waves generated by focuses of the strongest M9 earthquakes in the region of South Chilean coast, as well as in the region of Papua New Guinea and Solomon Islands, are most dangerous for this coast. Other tsunamigenic zones of the Pacific Ocean, by virtue of their geographical position, orientation of focuses, and absence of pronounced channels (submarine ridges) along paths of tsunami propagation are not dangerous for it even at a limit magnitude of submarine subduction earthquakes. The simulation results are compared with historical data about manifestations of distant tsunamis on the Russian Far East coast.

The numerical modelling of long wave propagation in the framework of non-linear dispersion models

Abstract The work is devoted to the questions of numerical modelling of long wave propagation, in particular tsunami waves, in the framework of non-linear dispersion models of the Boussinesq and Korteweg-de Vries type. The first part of the work includes a classification of some known mathematical models, in terms of dispersion correlation, phase and group velocities. Problems arising on the construction of finite-difference approximations of non-linear dispersion models are discussed in the second part of the work, special attention is given to the questions of constructing discrete boundary conditions. In the conclusion the results obtained in the course of numerical experiments and estimation of specifics of finite-difference models, and the contribution of non-linear dispersion effects in the process of wave propagation in the coastal zone, are discussed. The results of calculations of tsunami wave propagation in a wave tube with real bathymetry, are given.

Assessment of tsunami hazard due to regional and remote sources: The Coast of the Sea of Okhotsk

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.

Some approaches to local modelling of tsunami wave runup on a coast

Abstract This paper presents a method for the calculation of the tsunami wave runup on an actual coast. This method consists in preliminary study of peculiarities of wave patterns near the coast for a series of simplified model water areas inheriting the basic characteristics of the considered fragment of the coastal zone and the use of the obtained results for the interpretation of the complicated runup pattern for a real coast. The results presented here are related to modelling tsunami waves runup on a part of the coast of the Bay of Bengal.

Principles of numerical modeling applied to the tsunami problem

[2] In our paper, we formulate the principles of using computational tools to solve applied problems of tsunami oriented to the support of decisions by managers in critical situations [Shokin and Chubarov, 1999]. [3] From hereon we shall use term “tsunami” to denote the entire complex of catastrophic impacts caused by the waves in the basins and adjacent territories of the coast. The nature and spectral characteristics of these waves are usually associated with long surface gravity tsunami waves. [4] Similarly to other natural and anthropogenic catastrophes, tsunamis pass three stages in their development: stage before crisis, crisis, and stage after crisis. [5] Each of these stages is characterized by its duration, spatial scale, localization, and specific impact on the population involved in the crisis. Each stage requires specific methods of control and formulation of the list of problems, the important place in the solution of which is occupied by the methods of computational modeling. Specific limitations are imposed on mathematical models, numerical algorithms, technologies of calculation, character and volume of the results, means of their presentation (including visualization) means, protocols, and addressing of their spreading. [6] Leaving a number of provisions formulated above without consideration for a certain period of time we shall discuss the requirements, which the computational tools should satisfy. These tools are allowed by the scientific community for determining the vital characteristics of tsunami that are impossible or difficult to obtain using alternative sources (field

New Potentialities of Computational Experiment in Tsunami Problem

Computational experiment in tsunami problems is specified first of all by the multifactor physical process including the generation of the initial perturbation (Tsunami source) resulting from an underwater earthquake, volcano eruption or another similar large-scale hazard, propagation of the wave in deep ocean and its transformation in the coastal zone, interaction with floating and fixed objects and its running up on the shore.