L. I. Lobkovsky

Numerical Modeling of Sediment Mass Sliding and Tsunami Generation: The Case of February 7, 1963, in Corinth Gulf, Greece

Numerical modeling of a landslide process at the continental slope by taking into account slope parameters is performed for the tsunami event of February 7, 1963, reported in the Corinth Gulf, central Greece. A layered sediment structure was considered, and an initial external dynamic action at the landslide process was introduced. The results obtained were quite consistent with the observational runup data as well as with the results arrived at by conventional rigid-body and viscous-fluid models. However, this approach permits to describe in detail the formation of several wave groups and particular tsunami characteristics that are strongly dependent on the landslide model.

On Risk Assessment and Sustainable Industrial Development of Shelf Zones

Shelf zones of the Black Sea and the Caspian Sea become quickly major areas of industrial and technological development owing to growing population in these regions and vast natural resources available in these areas. Understanding and assessment of risks of natural and human‐made hazards in these areas contributes to strengthening the scientific and technological basis of a number of industries. Results of numerical modeling of the pollution transport and dispersal in the Caspian Sea are reported in this paper. Also we discuss applications of the observation system designed on drilling platforms to monitor coastal zone geophysical and ecological hazards. Our modeling and monitoring system can provide a reliable control of ecological situation in coastal zones of the Black Sea and the Caspian Sea and forecast possible hazardous changes.

Economic optimization of specifications for geoecological monitoring systems

The problem of incomparability of errors of 1st and 2nd kind (of false alarm and of missing of real danger) became solved after degrees of ecological disasters began to be expressed monetary. Requirements to reliability of monitoring systems (MS) signals are deduced from ratio of expenses of different kind. The sufficient condition of MS economic efficiency is resulted also. These results should be considered by working out specifications on MS.

Source mechanism of the tsunami of 2004 in the Indian Ocean: Analysis and numerical simulation

The tsunami in the Indian Ocean caused by the earthquake of December 26, 2004, near Sumatra Island had catastrophic consequences in coastal areas of many countries in this region. Notwithstanding extensive investigations of this phenomenon at various laboratories of the world, the focal mechanism of the aftershock remains unclear. The paper analyzes possible seafloor movements in the source area of the earthquake on the basis of the keyboard model of tsunamigenic earthquakes and describes numerical simulation of the generation, propagation, and runup of water surface waves in terms of this model involving vertical displacements of seafloor “keyboard-blocks.” It is shown that generated tsunami waves are essentially dependent on the combination of keyboard-block movements, which results in an irregular distribution of maximum runups along the shoreline. If the oblique nature of the subduction zone associated with the Sumatra-Andaman earthquake of December 26, 2004, is taken into account, the model results fit well the runup values observed at the Thailand shoreline. It is noted that this model of the subduction zone accounts more adequately for the tsunami wave field pattern in both areas of the Indian Ocean and other water areas such as the region of the Kurile-Kamchatka Island Arc and the Sea of Okhotsk.

Implications of the seismic source dynamics for the characteristics of a possible tsunami in a model problem of the seismic gap in the Central Kurile region

[1] Various scenarios of earthquakes and the associated tsunami wave generation are numerically simulated. It is shown that, depending on the chosen dynamic source parameters in the central seismic gap zone of the Kurile-Kamchatka arc, the characteristics of tsunami waves in the water area of the Sea of Okhotsk and Kurile-Kamchatka zone can differ dramatically, from insignificant inundation of Sakhalin and Kamchatka coasts to a catastrophic run-up of waves up to 8 m in height. Detailed numerical constraints on the tsunami wave run-up are obtained for a number of points of the Sakhalin coastline, the form of the first waves climbing the coast is determined, and the run-up velocity characteristics are computed.

To analysis of source mechanism of the 26 December 2004 Indian Ocean tsunami

[1] Tsunami in the Indian Ocean generated by a strong earthquake in Sumatra-Andaman region on 26 December 2004 led as known to catastrophic results at the coast of many countries of this region. In spite of intensive study of this event by a number of groups, the character of seafloor displacements in the source during this earthquake remains to be controversial. In this work, it is performed an analysis of physical aspects of similar earthquakes on the basis of keyboard model of tsunamigenic earthquakes. The numerical simulation of generation, propagation and run-up of surface water waves on the basis of simplified keyboard model of tsunamigenic earthquakes with vertical displacements of keyboard blocks in approximative geometry (without taking into account the real bathymetry) is also performed. It is obtained that tsunami waves generated by various combinations of keyboard block displacements are essentially different in character which fact leads to quite different picture of maximum run-up distribution along the near-field coast. It is performed the estimative computation for 26 December 2004 SumatraAndaman earthquake with taking into account of oblique character of the subduction zone characteristic for this earthquake. The computations performed explain the complex character of run-up distribution at nearest to the source coasts and are in a good agreement with run-up values at the Thailand coast. It is noted that such a model can account for more adequately the tsunami wavefield character in another regions of the Indian and the Pacific Ocean basins as well.

Modeling Features of Both the Rupture Process and the Local Tsunami Wave Field from the 2011 Tohoku Earthquake

This paper presents the numerical simulation of the displacement distribution in the source of the 2011 Tohoku earthquake, based on the following assumptions on the geometry and mechanics of the source, and features of the subduction zone structure: displacement in the source is determined by specifying a reduced friction coefficient on the plate interface, considering heterogeneous initial stress state of the medium; source is considered in the framework of the Lay–Kanamori model as two consecutive subsources with deep and shallow location; a nonlinear elasto-plastic model of behavior of the medium under the Mohr–Coulomb yield criterion is applied. For the numerical modeling, a program code FLAC 3D implementing an explicit finite-difference scheme solution is used. The resulting lithosphere displacement distribution was used for computation of the tsunami source for given earthquake. The numerical simulation of the corresponding tsunami wave field was performed.

A method of ecological and economic risk assessment during the development of the shelf based on mathematical modelling

This paper proposes a method of mathematical modelling of ecological risk based on a synthesis of dynamic and probabilistic risk assessment techniques. The probability of assessment of an acceptable probability of an anthropogenic impact to minimize economic costs is proposed. The dependence of an acceptable probability of an anthropogenic impact on the ecological risk is demonstrated with an example calculation. The results of the modelling of the state of a shelf ecosystem based on the dynamic model are used for the calculation as source information. Based on this synthesis, the calculation results bring about the opportunity to balance ecological–economic goals of achieving safe development of the shelf and to satisfy the involuntary necessity to reduce the costs on environmental protection measures, while maintaining the priority of environmental requirements.

Numerical simulation of propagation of the Black Sea and the Azov Sea tsunami through the Kerch Strait

The present paper deals with the potential strong tsunamigenic earthquakes with the sources localized in the Black and Azov seas at the entrance and exit of the Kerch Strait, respectively. Since, at present time, the tsunami hazards are usually assessed for the critical earthquake magnitude values, potential strong earthquakes with a magnitude M = 7 are studied. The seismic sources of elliptical form are considered. When choosing the source location in the northeast of the Black Sea, the most seismically dangerous areas of the basin under consideration are allowed for. Numerical simulation is carried out within the framework of the nonlinear shallow water equations with the dissipative effects taken into account. Two possible scenarios of tsunami propagation at the chosen source locations are analyzed. The wave characteristics are obtained for a tsunami wave motion both from the Black Sea through the Kerch Strait to the Azov Sea. The symmetrical problem for a tsunami wave propagation from the Azov Sea through the Kerch Strait to the Black Sea is also considered. Spectral analysis of the tsunami wave field is carried out for the studied basin. The wave and energy characteristics of the tsunami waves in the area of the bridge across the Kerch Strait are subjected to the detailed examination and assessment.

Geodynamic Evolution Model of the Major Structures of Amerasian Basin

We have analyzed the geodynamic evolution of the lithosphere and upper mantle of the Amerasian basin based on the stress-strain state simulation. It is shown that the asthenospheric spreading in the return upflow region of the mantle convection, results in formation of two local uplifts, which can be interpreted as Lomonosov Ridge and Mendeleev/Alfa Ridge. The further long-term action of the mantle convection leads to formation of Makarov and Podvodnikov Basins.