Bulgarian tsunami on 7 May 2007: numerical investigation of the hypothesis of a submarine-landslide origin

2018 ◽  
Vol 477 (1) ◽  
pp. 303-313 ◽  
Author(s):  
Oleg I. Gusev ◽  
Gayaz S. Khakimzyanov ◽  
Leonid B. Chubarov

AbstractWe 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.

Author(s):  
Gayaz S. Khakimzyanov ◽  
Oleg I. Gusev ◽  
Sofya A. Beizel ◽  
Leonid B. Chubarov ◽  
Nina Yu. Shokina

AbstractNumerical technique for studying surface waves appearing under the motion of a submarine landslide is discussed. This technique is based on the application of the model of a quasi-deformable landslide and two shallow water models, namely, the classic (dispersion free) one and the completely nonlinear dispersive model of the second hydrodynamic approximation. Numerical simulation of surface waves generated by a large model landslide on the continental slope of the Black Sea near the Russian coast is performed. It is shown that the dispersion has a significant impact on the picture of propagation of tsunami waves on sufficiently long paths.


2001 ◽  
Vol 1 (4) ◽  
pp. 243-250 ◽  
Author(s):  
E. Pelinovsky ◽  
T. Talipova ◽  
A. Kurkin ◽  
C. Kharif

Abstract. The problem of tsunami wave generation by variable meteo-conditions is discussed. The simplified linear and nonlinear shallow water models are derived, and their analytical solutions for a basin of constant depth are discussed. The shallow-water model describes well the properties of the generated tsunami waves for all regimes, except the resonance case. The nonlinear-dispersive model based on the forced Korteweg-de Vries equation is developed to describe the resonant mechanism of the tsunami wave generation by the atmospheric disturbances moving with near-critical speed (long wave speed). Some analytical solutions of the nonlinear dispersive model are obtained. They illustrate the different regimes of soliton generation and the focusing of frequency modulated wave packets.


Author(s):  
A. Yu. Belokon ◽  

This paper is devoted to computational modelling of tsunami wave propagation and runup to the shore for some points on the Russian, Turkish, Bulgarian and Ukrainian coasts of the Black Sea. The nonlinear long wave model was used to solve the problem of wave propagation from hydrodynamic tsunami sources, which can constitute the greatest potential danger for the studied coast areas. The hydrodynamic sources were set in the form of an elliptical elevation, the parameters of which were chosen according to the sea level response to an underwater earthquake of magnitude 7. All the sources were located in seismically active areas, where tsunamigenic earthquakes had already occurred, along the 1500 m isobath. Near each of the studied points in the area above 300 m depths, we calculated marigrams, i.e. time-series of sea level fluctuations caused by the passage of waves. Then, a one-dimensional problem of tsunami propagation and run-up on the coast was solved for each of the points under study, where the obtained marigrams were used as boundary conditions. Peculiarities of tsunami wave propagation have been shown depending on the bottom and land relief in the studied areas of the Black Sea. Estimates have been obtained of the sea level maximum rise and fall during surge and subsequent coastal drainage for the characteristic scales of relief irregularity at different points. For possible tsunamigenic earthquakes, the largest splashes may occur in the region of Yalta (2.15 m), Cide (1.9 m), Sevastopol (1.4 m), and Anapa (1.4 m). Tsunami propagation in the Feodosiya and Varna coastal areas is qualitatively similar, with maximum wave heights of 0.64 m and 0.46 m, respectively. The coastlines of Evpatoriya (0.33 m) and Odessa (0.26 m) are least affected by tsunami waves due to the extended shelf.


2018 ◽  
Vol 7 (3) ◽  
pp. 1233
Author(s):  
V Yuvaraj ◽  
S Rajasekaran ◽  
D Nagarajan

Cellular automata is the model applied in very complicated situations and complex problems. It involves the Introduction of voronoi diagram in tsunami wave propagation with the help of a fast-marching method to find the spread of the tsunami waves in the coastal regions. In this study we have modelled and predicted the tsunami wave propagation using the finite difference method. This analytical method gives the horizontal and vertical layers of the wave run up and enables the calculation of reaching time.  


Author(s):  
Hryhorii MOROZ

The anthropogenic transformation of soil physical properties of the transition stripe from the dry to the middle steppe in the Northwest of the Black Sea region is considered and analyzed on the basis of comparison of indicators characterizing the properties of the cultivable and subcultivable horizons. The signs of negative influence of agricultural use on the most important indices of physical properties of soils are investigated. Significant degradation of the physical properties of the arable horizons (in comparison with tillable and subcultivable horizons), as well as deterioration of the water resistance of the structure of the tillable horizons (compared to the arable) was revealed. The geographic regularities of agrogenic evolution of sodic and residual-sodic calcic chernozems and gypsic kastanozems are established.


Author(s):  
Ali Abdolali ◽  
James T. Kirby

Most existing tsunami propagation models consider the ocean to be an incompressible, homogenous medium. Recently, it has been shown that a number of physical features can slow the propagation speed of tsunami waves, including wave frequency dispersion, ocean bottom elasticity, water compressibility and thermal or salinity stratification. These physical effects are secondary to the leading order, shallow water or long wave behavior, but still play a quantifiable role in tsunami arrival time, especially at far distant locations. In this work, we have performed analytical and numerical investigations and have shown that consideration of those effects can actually improve the prediction of arrival time at distant stations, compared to incompressible forms of wave equations. We derive a modified Mild Slope Equation for Weakly Compressible fluid following the method proposed by Sammarco et al. (2013) and Abdolali et al. (2015) using linearized wave theory, and then describe comparable extensions to the Boussinesq model of Kirby et al. (2013). Both models account for water compressibility and compression of static water column to simulate tsunami waves. The mild slope model is formulated in plane Cartesian coordinates and is thus limited to medium propagation distances, while the Boussinesq model is formulated in spherical polar coordinates and is suitable for ocean scale simulations.


2018 ◽  
Vol 203 ◽  
pp. 01001 ◽  
Author(s):  
Vo Nguyen Phu Huan ◽  
Indra Sati H. Harahap ◽  
Wesam Salah Alaloul

Submarine landslide is the most serious threat on both local and regional scales. By way of addition to destroying directly offshore structures, slope failures may also generate destructive tsunami waves. This study has developed a numerical model based on the Smoothed Particle Hydrodynamics (SPH) method to predict four stages of generation, propagation, run-up, and impact of tsunami phenomenon. The numerical predictions in the research were validated with results in the literature and experimental tests. The results of the physical and numerical results presented in this study effort to develop these rule of thumbs to clearly understand some of the mechanics that may play a role in the assessment of tsunami waves.


2015 ◽  
Vol 9 (6) ◽  
pp. 6471-6493 ◽  
Author(s):  
M. P. Lüthi ◽  
A. Vieli

Abstract. Glacier calving can cause violent impulse waves which, upon landfall, can lead to destructive tsunami-like waves. Here we present data acquired during a calving event from Eqip Sermia, an ocean-terminating glacier in West Greenland. During an exceptionally well documented event, the collapse of 9 × 105 m3 ice from a 200 m high ice cliff caused an impulse wave of 50 m height, traveling at a speed of 25–30 m s-1. This wave was filmed from a tour boat in 800 m distance from the calving face, and simultaneously measured with a terrestrial radar interferometer and a tide gauge. Tsunami wave run-up height on the steep opposite shore in 4 km distance was 10–15 m, destroying infrastructure and eroding old vegetation. These observations indicate that such high tsunami waves are a recent phenomenon in the history of this glacier. Analysis of the data shows that only moderately bigger tsunami waves are to be expected in the future, even under rather extreme scenarios.


2021 ◽  
Author(s):  
Irene Manzella ◽  
Symeon Makris ◽  
Federico Di Traglia ◽  
Karim Kelfoun ◽  
Paul Cole ◽  
...  

<p>As demonstrated by the Anak Krakatau eruption-induced flank collapse in 2018 in Indonesia, tsunamis generated by large mass flows like landslides and pyroclastic density currents can have devastating effects in volcanic areas. However, these phenomena are still poorly understood as they are unusual and complex events, largely unpredictable and often poorly constrained. </p><p>Stromboli is one of the most active volcanoes in the world, extensively monitored and studied in the last few decades. Many tsunamigenic landslides (sub-aerial and/or submarine) have taken place; at least seven have occurred in the last 150 years and a devastating one is believed to have reached the coast of Naples, at more than 200 km distance, during the Middle Ages. Because the level of activity of the volcano has remained similar ever since and the likelihood of such disastrous events is not negligible, the hazard related to tsunamigenic mass flows in this area needs to be carefully assessed.</p><p>Associated with the 3<sup>rd</sup> of July 2019 eruption, at least three mass flows were triggered along the Sciara del Fuoco slope; two subaerial Pyroclastic density currents (PDCs) and a submarine landslide. Simultaneously, three buoys registered the height of the resulting tsunami wave ranging from 0.2 m in front of the Ginostra village to 1.5 m in front of the Sciara del Fuoco. Thanks to the dense monitoring network and the accurate bathymetry survey carried out by the IGAG-CNR, these events have been well constrained. </p><p>The tsunami waves studied here are smaller than those that could constitute a threat for the population living in this area, nevertheless they can be used to characterize the behaviour of the tsunamigenic mass flows. Back analysis of these events were undertaken with the two-fluids version of VolcFlow; this is a continuum mechanics model based on the depth-average approximation that has been developed for the simulation of volcanic flows. VolcFlow can take into account several different rheologies for each of the two fluids. In the present case, one fluid was used for the water body and one for simulating the mass flow. For the latter one, a constant retaining stress type of rheology was used (Dade and Huppert, 1998). Backanalysis suggested that it was the PDC which generated the tsunami wave during the events of July 2019 and best fitting simulations identified a constant retaining stress of 7kPa. With these input parameters it has been possible to run a large number of numerical simulations of possible scenarios. This has allowed to assess threshold values of volume and discharge of mass flows which could generate significant and potentially destructive tsunami waves. This constitutes an important input to improve early warning systems and to reduce the risk related to these unpredictable but extremely dangerous phenomena.</p>


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