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.

Reasons and consequences of coast destruction in the Preserve Tauric Chersonesus included in the list of UNESCO World Heritage Sites are considered.Wind waves are the basic hydrodynamic factor leading to the destruction of the ancient city coast. The most significant retreat of the cliffs and the intense destruction of archaeological sites are observed in the northern sector of the reserve territory. This sector of the coast can be identified as a priority one for taking complex coastal protection measures. Conceptual principles of creating coastal protecting structures permitting to retain the coast historical landscape are analyzed. The wind wave fields nearby the Chersonesus ancient settlement coast are numerically simulated with high spatial resolution using the SWAN model based on the method of nested grids. At the same wind velocity the most intense waves are generated by the northwestern wind. Wave height, calculated for wind velocities of 15 and 25 m/s immediate close to the coastline vary less considerably than in the seaward part of the water area. The wind wave fields are simulated under various variants of arranging hydrotechnical structures on the Black Sea adjacent area. The main coastal protection installations, which should provide damping storm surge energy reaching the shore, were considered the underwater breakwaters placed roughly parallel to the coastline. When running a series of numerical experiments the length and number of breakwaters, as well as the distance from the shore to the place of their location ranged. The schemes of allocation the submerged breakwaters are proposed which both provide effective energy dissipation of storm waves approaching the coastline and retain possibility of water exchange with the adjacent waters during the periods of weak winds.

Поступила в редакцию 01.03.2018 г., после доработки-04.04.2018 г. В рамках нелинейной модели длинных волн выполнено численное моделирование эволюции цунами в Черном море, вызванного Ялтинским землетрясением 12 сентября 1927 г. Реализовано две задачи о распространении волн цунами из эллиптического очага: для всей акватории Черного моря и для локального участка южной части Крымского побережья. Расчеты для первого численного эксперимента проводились на 30-секундной батиметрической сетке Черного моря. Для ряда пунктов Крымского и Кавказского побережий рассчитаны колебания уровня моря, которые сопоставлены с имеющимися записями мареографов. Амплитуды модельных колебаний уровня в прибрежной зоне при распространении волн цунами оказались больше амплитуд, зафиксированных инструментально, что связано с неточностью моделирования очага генерации цунами вследствие малого объема информации о данном событии. Во всех пунктах, кроме Ялты, колебания уровня моря не превысили по высоте начальное возвышение очага цунами. В Ялте высота волн может достигать 2 м, в Евпатории-0,2 м, в Севастополе-0,4 м, в Феодосии-0,5 м, в Керчи-0,4 м, в Новороссийске-0,5 м, в Туапсе-0,3 м, в Батуми-0,5 м. Во втором численном эксперименте проведен расчет эволюции цунами с последующим накатом волн на Южный берег Крыма. Использована батиметрическая сетка с 50-метровым разрешением. Для 10 пунктов Южного берега Крыма рассчитаны колебания уровня моря во время цунами и оценены амплитудные характеристики при накате волн на берег. Наиболее подвержен воздействию волн участок побережья в районе Ялты, Никиты и Гурзуфа. Высота наката волн цунами на берег в Никите может достигать 2 м, а понижение уровня моря при осушении побережьяболее 3 м. Ключевые слова: нелинейные длинные волны, численное моделирование, цунами в Черном море, Ялтинское землетрясение 12 сентября 1927 г., цунамиопасность Черноморского побережья. Благодарности: работа выполнена в рамках государственного задания по теме № 0827-2018-0004 «Комплексные междисциплинарные исследования океанологических процессов, определяющих функционирование и эволюцию экосистем прибрежных зон Черного и Азовского морей» (шифр «Прибрежные исследования»).

This work is focused on numerical simulation of the interaction of a solitary surface wave with a submerged rectangular breakwater in the constant depth model basin using the non-hydrostatic hydrodynamic model SWASH (Simulating WAves till SHore). The features of the transformation of a wave passing over an obstacle with the width and height changes of the breakwater were investigated. Based on numerical experiments, the transformation coefficients for the soliton and the zone of its attenuation area behind a breakwater were calculated. The localization of the region of maximum attenuation of the wave passing beyond the breakwater is determined. The analysis of the spatial structure features of free-surface fluctuations caused by the interaction of a soliton with a breakwater is carried out. The depthaveraged orbital fluid velocities are calculated and the dependence of their values and directions on the geometric parameters of the underwater obstacle is determined.