Leonid B. Chubarov

On the contribution of the horizontal sea-bed displacements into the tsunami generation process

The main reason for the generation of tsunamis is the deformation of the bottom of the ocean caused by an underwater earthquake. Usually, only the vertical bottom motion is taken into account while the horizontal co-seismic displacements are neglected in the absence of landslides. In the present study we propose a methodology based on the well-known Okada solution to reconstruct in more details all components of the bottom coseismic displacements. Then, the sea-bed motion is coupled with a three-dimensional weakly nonlinear water wave solver which allows us to simulate a tsunami wave generation. We pay special attention to the evolution of kinetic and potential energies of the resulting wave while the contribution of the horizontal displacements into wave energy balance is also quantified. Such contribution of horizontal displacements to the tsunami generation has not been discussed before, and it is different from the existing approaches. The methods proposed in this study are illustrated on the July 17, 2006 Java tsunami and some more recent events.

Simulation of surface waves generated by an underwater landslide in a bounded reservoir

Abstract Equations of a landslide motion over an uneven underwater slope subject to gravity and buoyancy forces, water friction and resistance are presented. A simulation of surface waves generated by a landslide in a bounded reservoir with a parabolic bottom profile has been performed within the nonlinear shallow water equations, and the results of that simulation are given. The influence of the parameters of the motion equation on the maximal splashing size is studied numerically.

Mathematical Modeling in Application to Regional Tsunami Warning Systems Operations

Catastrophic tsunamis that flooded the ocean coast in the past had taken many human lives and destroyed the infrastructure of the coastal areas in the Pacific and elsewhere. Recent tragic events in the Indian Ocean motivated governments to develop new and improve the existing tsunami warning systems capable to mitigate the impact of catastrophic events. In the future, regional tsunami warning systems will be integrated into a network including both the systems currently being developed and the existing warning systems (in the past, tsunami warning systems had been deployed to protect the coastal areas in Japan, USA, Russia, Australia, Chile and New Zealand).

Numerical Modelling of Surface Water Waves Arising Due to Movement of Underwater Landslide on Irregular Bottom Slope

The work is devoted to the numerical modelling of surface water waves generated by a moving underwater landslide on irregular bottom. Currently the works of other authors consider flat bottoms only. The modelling is done in the framework of the shallow water model with taking into account bottom mobility. The equations are obtained for an underwater landslide movement under the action of gravity force, buoyancy force, friction force and water resistance force. The predictor-corrector scheme [5], preserving the monotonicity of the numerical solution profiles in a linear case, is used on adaptive grids, which are generated using the equidistribution method [7]. The scheme is tested for the problem with a known analytical solution, describing the wave generation by a nondeformable body, which moves with a constant velocity on a horizontal bottom. The analysis is done for an irregular bottom of the dependencies of wave regime characteristics on bottom slope, initial landslide depth, its length and width.

A combined computational algorithm for solving the problem of long surface waves runup on the shore

Abstract 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.

Some Features of the Landslide Mechanism of Surface Waves Generation in Real Basins

We present the results of numerical modelling of surface wave generation by the movement of submerged deformable body along the slope, which simulates the real coastal slope. The multiparametric computations are carried out within the shallow water approximation that allowed to determine the dependence of wave pattern on the depth of landslide submergence, length and thickness of the body, relative density, friction coefficient, and slope geometry. The main attention is focused on the effects resulted from the heterogeneity of depths, which simulates specifics of real water basins.

To the numerical simulation and propagation of tsunami according to the shallow water equations

The present paper gives the numerical simulation of tsunami generation and propagation in the ocean with real bathymetry. For the describing of this processes nonlinear shallow water equations are used, which are solved with the help of finite-difference method. Here is considered the problem of tsunami generation by bottom displacements, moving with the any given velocity. The computed displacement of water surface and velocity field in the generation area for a typical seismic source (Alexeev, Gusiakov 1973) is used to specify the initial conditions for computing the propagation of tsunami near the Kuril Islands. The wave field of tsunami and mareograms on the shore line are found. The comparison of the results with those for linear model of the tsunami propagation is carried out.

ON NUMERICAL METHODS FOR SOLVING RUN-UP PROBLEMS. COMPARATIVE ANALYSIS OF NUMERICAL ALGORITHMS AND NUMERICAL RESULTS.

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.

Information and telecommunication systems for emergency management

Collecting and sharing timely, reliable and accurate information during a crisis is critical to improving humanitarian response, maximizing resources and minimizing human suffering. The faster humanitarian organizations are able to collect, analyse and disseminate critical information, the more effective the response becomes and the more lives are potentially saved. Though humanitarian information functions, systems and tools have improved in the past five years, a combination of operational, funding and technical constraints, combined with a lack of awareness, continues to handicap information from becoming a core, wellresourced component of relief operations.

Finite-Difference Simulation of Tsunami Propagation

The present paper gives a numerical simulation of tsunami propagation in the ocean with a real bathymetry. The computed displacement of the water surface in the generation area for a typical seismic source (Alexeev, Gusiakov /1/) is used to specify initial conditions for computing the propagation of a tsunami near the Kuril Islands. The nonlinear long-wave equations are adopted as a description of tsunami behavior and solved numerically by a finite-difference method. The wave field of tsunami and mareograms at the shore line are found. The comparison of the results with those for linear model of the tsunami propagation is carried out.