Numerical Simulation of Tsunami in the Black Sea Caused by the Earthquake on September 12, 1927

Abstract

Within the framework of the nonlinear model of long waves, the numerical simulation of the tsunami evolution in the Black Sea caused by the Yalta earthquake of September 12, 1927 is performed. Two problems on propagation of tsunami waves from the elliptical source are solved: for the whole Black Sea water area and for the local part of the Crimea Southern coast. The calculations for the first numerical experiment are carried out on a 30-second bathymetric grid of the Black Sea. The sea level oscillations for several points on the Crimean and Caucasian coasts are calculated and compared with the available records of the tide gauges. The amplitudes of the model level oscillations in the coastal zone during propagation of tsunami waves are larger than those recorded instrumentally. This fact is related to inaccuracy in modeling the tsunami generation site due to small amount of information on this event. In all the points, except for Yalta, the sea level oscillations did not exceed the height of the tsunami center initial elevation. In Yalta the wave height can attain 2 m, in Evpatoria-0.2 m, in Sevastopol-0.4 m, in Feodosia-0.5 m, in Kerch-0.4 m, in Novorossiysk-0.5 m, in Tuapse-0.3 m and in Batumi-0.5 m. The second numerical experiment implies calculation of the tsunami evolution followed by the wave run-up on the Crimea Southern coast. The 50-meter bathymetric grid is applied. For 10 points of the Crimea Southern coast, the sea level oscillations occurring during tsunamis are calculated and the amplitude characteristics during the wave run-up are assessed. The coastline in the region of Yalta, Nikita and Gurzuf is the most strongly affected. The height of the tsunami waves' run-up on the coast in Nikita can make up 2 m, and the sea level drop at draining the coast-more than 3 m.

Tsunami Hazard for the Crimean Coast of the Black Sea and the Kerch Strait at the Catastrophic Tsunamigenic Earthquakes, the Locations of which are Close to that of the Historical Yalta Earthquake on September 12, 1927

“…Comparing the work [13] that was carried out earlier for hypothetical sources of earthquakes localized before entering the Kerch Strait, and the present work, considering seismic sources located in the south-west of the Crimean Peninsula, it was shown that in earthquakes with the same magnitudes wave heights in the strait, in particular in the Crimean Bridge area, have significantly different values. Thus, for example, the maximum wave height at the eastern pillars of the Crimean Bridge, according to [13], was 1.5 m, and, according to the computations presented in this work, the tsunami wave height from the source located in the south-west of the Crimean Peninsula, at the eastern pillars of the bridge is 0.5 m. However, in the event of a catastrophic earthquake with a magnitude of M = 8 and with a seismic source located in the zone of active faults of the Crimean Peninsula Earth's crust, in the Kerch Strait, the possible maximum wave height in the region of the western pillars of the bridge is about 0.5 m, in the region of eastern pillars up to 1.9 m. Numerical modeling of the historical earthquake of September 12, 1927 off the coast of Crimea was also carried out in [8,9,11]. Computations in these works were carried out for similar forms of the earthquake source with a magnitude of M = 7.…”

“…Computations in these works were carried out for similar forms of the earthquake source with a magnitude of M = 7. Since the Crimean Peninsula coast and the northeastern part of the Black Sea were considered in detail in [8,11], the purpose of the present research was to estimate wave characteristics in Kerch Strait water area. Here, the virtual tide gauges were put, for comparison, in [8] and [11] only a few points on the Crimean coast and only one point at the Kerch Strait (Kerch) entrance could be found.…”

“…On September 12, 1927, at night a catastrophic tsunamigenic earthquake with a magnitude ranging within the interval M = 7-8 occurred on the Crimean Peninsula coast (see, for example, [1][2][3][4][5][6]). Its center was under the seabed, south of Yalta and was extended along the coast.…”

“…The seismic and tsunami hazard assessments of the Black Sea, both Russian and other coasts of this water area, have been the subject of many works (see, for example, [7][8][9][10][11][12][13][14][15][16][17][18]). However, despite the proposed analytical methods and models for simulation of the generation and propagation of tsunami waves, the question of the possible danger of the Black Sea tsunami remains relevant, in particular, in connection with the operation of the recently built Crimean Bridge across the Kerch Strait.…”

“…Complex geological conditions such as seismicity, tectonic fault and weak soils [19][20][21] require the most detailed analysis of all possible events that affect the seismic and tsunami stability of the unique structure constructed. In this regard, the work examines in detail the possibility of repeating the historical catastrophic event of September 12, 1927 with numerical modeling of earthquake sources of various configurations while maintaining the localization of the source in the southeast of the Crimean Peninsula.…”