The 1994 Shikotan earthquake tsunamis

The 1994 Shikotan earthquake was one of the greatest earthquakes in recent years with a magnitude ofM _s 8.0. A tsunami survey was conducted by Russian and U.S. geophysicists from October 16–30, 1994, less than two weeks after the earthquake. The survey results and a numerical hindcast simulation are reported. Tsunami focusing effect at locations supposedly sheltered by the island chain is discussed. Based on the obtained data, tsunamis which attacked Shikotan Island are characterized as long waves (the order of 10–20 min wave period) with a positive leading wave. Possible consequences of the positive leading wave form are discussed in relation to the observed minimal destruction of beach vegetation and relatively small transport of marine sediment onto the shore. The high-quality tide-gage record in Malokurilskaya Bay indicates the occurrence of a 53 cm subsidence at the site.     

The influence of the Kuril Islands on the penetration of tsunamis into the Sea of Okhotsk (on the example of the Japan tsunami on March 11, 2011)

The features of the propagation of the tsunami of March 11, 2011 in the northeastern Pacific have been studied with the aim of revealing the degree of influence of the Kuril Islands on the penetration of the tsunami in the Sea of Okhotsk. For this, a series of computational experiments have been performed within the shallow water theory using bathymetry (1) with and (2) without the Kuril Islands. The wave heights calculated have been analyzed, and the tsunami’s magnitude and intensity in the Sea of Okhotsk have been estimated. The computational experiments performed allow assessment of a decrease in the tsunami intensity while passing the Kuril Islands.     

Run-up of surface waves on a sea wall built on a convex bottom profile

Wave run-up on a sea wall built on a convex bottom profile is studied in the framework of linear shallow water theory. When the wall is located in “deeper water,” a wave is reflected from the wall without changing its shape and phase, which is fully consistent with classical considerations. If the wall is shifted towards the shore, the shape of the wave changes in a complex way. Note that the wave phase changes to the opposite in the limiting case when the wall is located right on the shore. The role of nonlinear effects is studied by means of numerical simulations using nonlinear shallow water theory. It is shown that the contribution of nonlinear effects and breaking is high on a convex-shaped beach, which makes the structure of the wave field rather complicated.     

Polynomial approximations of Berkhoff's model for waves in a basin of variable depth

On the basis of the polynomial approximation of the dispersion relation for gravity waves, a generalized version of Berkhoff's model for a non-stationary case has been obtained. The standard problem of the transition of a wave from deep water into shallow water in a basin with a slowly varying topography is applied to study analytically Berkhoff's model polynomial approximations. It has been demonstrated that all qualitative characteristics of wave transformation can be described in the framework of this model.Translated by V. Puchkin.     

Scattering of surface waves in a basin with a statistically uneven bottom

The propagation of surface waves over a statistically uneven bottom is considered on the basis of equations of the linear potential theory. The expression which emphasizes the dispersion influence is obtained for the spatial decrement of the average field. The north-east Pacific is considered as an example.Translated by Mikhail M. Trufanov.     

A short cut numerical method for determination of periods of free oscillations for basins with irregular geometry and bathymetry

A short cut numerical method for evaluation of the modes of free oscillations of the basins which have irregular geometry and bathymetry is presented in this paper. In the method, a single wave is inputted to the basin as an initial impulse. The respective agitation in the basin is computed by using the numerical method solving the nonlinear form of long wave equations. The time histories of water surface fluctuations at different locations due to propagation of the waves in relation to the initial impulse are stored and analyzed by the fast Fourier transform technique (FFT) and energy spectrum curves for each location are obtained. The frequencies of each mode of free oscillations are determined from the peaks of the spectrum curves. The method is tested by using regular shaped flat bottom basins with different depths. The computed periods of free oscillations are compared with the theoretical values. The accuracy and performance of the method are discussed. As a case study for the application to the basins of irregular shape and bathymetry, the periods of free oscillations of the sea of Marmara is determined and discussed.     

Nonreflected vertical propagation of acoustic waves in a strongly inhomogeneous atmosphere

Using the linear theory of waves in a compressible atmosphere located in a gravitational field, we found a family of sound speed profiles for which the wave field can be represented by a traveling wave with no reflection. The vertical flux of wave energy on these nonreflected profiles is retained, which proves that the energy transfer may occur over long distances.     

Run-Up of a Nonlinear Monochromatic Wave on a Plane Beach in Presence of a Tide

Oceanology - Abstract—The nonlinear problem of run-up of a long wave on a plane beach in presence of a tide is solved within nonlinear shallow water theory using the Carrier–Greenspan...     

Influence of Nonlinear Interaction on the Evolution of Waves in a Shallow Basin

Izvestiya, Atmospheric and Oceanic Physics - The influence of nonlinear interaction of oppositely directed nonlinear waves in a shallow basin is studied theoretically and numerically within the...