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.     

Registration of weak ULF/ELF oscillations of the surface electric field strength

Measurements of the atmospheric electric field strength made by an electrostatic fluxmeter with a unique threshold sensitivity for such devices (6 × 10^–2–10^–3 V m^–1 Hz^–1/2 in the 10^–3–25 Hz frequency range) and wide dynamic (120 dB) and spectral (0–25 Hz) ranges, are presented. The device parameters make it possible to observe the electric component of global electromagnetic Schumann resonances and long-period fluctuations in the atmospheric electric field strength.     

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.