Studying Resonance Oscillations in the Eastern Part of the Posyet Bay

The field experiment with the installation of autonomous pressure gages in the Troitsa and Vityaz’ bays was held for studying the specific features of free surface oscillations in the Posyet Bay (the Sea of Japan). The interpretation and joint analysis of measurement data allowed obtaining the datasets of spatiotemporal parameters for free oscillations calculated using the spectral-difference model and for forced oscillations in the form of the response to the forcing with the periods of 10–50 minutes in the numerical model of shallow water with the difference approximation on the irregular triangular grid. The position of peaks on the model resonance curves and the values of frequencies of free oscillations are consistent with the position of clearly pronounced peaks of the energy spectrum from field data. This indicates the possibility of significant resonance enhancement of the amplitude of oscillations by periodic wind effects and incoming wave effects.     

On intense internal waves in the coastal zone of the Peter the Great Bay (the Sea of Japan)

Spatiotemporal variability of the internal gravity waves in the Sea of Japan shelf zone (in the Peter the Great Bay) is analyzed basing on the results of the experimental data processing. It is shown that, as for autumn water structure, the tidal internal waves moving towards the coast are transformed due to the non-linear effects and may reach significant amplitudes (of about 10 meters). Such waves are usually referred to as strongly non-linear. The main characteristics of such intense waves were estimated. An example of the disintegration of solitary temperature depression into the package of short-period intense internal waves is given.     

The spatiotemporal analysis of the bottom geomorphology in Peter the Great Bay of the Sea of Japan

Based on the shipboard measurements data, GTOPO1 and ASTER satellite information, GEBCO databases, and bathymetry maps, a digital elevation model encompassing the shelf of Peter the Great Bay of the Sea of Japan is constructed. By two-dimensional singular spectral analysis, the scale decomposition of the surface of the shelf relief is made into the components with the main tectonic structure, the secondary folding zones, and the sedimentation landforms. A comparison between the found elements and the geological data on South Primorye is performed to specify the age of the tectonic units of different scale.     

About a mechanism of the formation of sedimentary waves on the shelf of the Sea of Japan

The existence of sedimentary waves at depths ranging from 50 to 100 m in Peter the Great Bay of the Sea of Japan has been discovered and substantiated as a result of geological and geophysical experiments. The experimental and theoretical studies have made it possible to conclude that the sedimentary waves form in the depth range specified due to processes related to the disintegration of nonlinear gravity waves.     

Development of tomographic technology for the Earth’s crust in the shelf regions

On the basis of experimental data obtained during a comprehensive experiment in Vityaz Bay of the Sea of Japan using onshore laser strainmeters and a low-frequency hydroacoustic emitter generating complex phase-manipulated signals with a central frequency of 33 Hz, we developed the basic principles of contactless tomography of the Earth’s crust in the shelf regions of various seas, including those covered by ice, making it possible to determine efficiently the structure and composition of the upper Earth’s crust under seas.