Geophysical Survey

About: Geophysical Survey is a facility organization based out in Obninsk, Russia. It is known for research contribution in the topics: Geology & Seismology. The organization has 308 authors who have published 256 publications receiving 3067 citations. The organization is also known as: Federal State Institution of Science Geophysical Survey of the Siberian Branch of the Russian Academy of Sciences.

Standing waves in engineering objects of complex constructions

Abstract: According to the results of research on complex engineering objects, results were obtained that demonstrate significant deviations from the models of buildings and structures adopted as the basis for calculating seismic resistance and structural stability. First, it is the existence of reflecting seismic oscillations of the boundaries inside the building, when standing waves form a common field for the building as a whole and a local field for a part of the object. Secondly, a block structure of the object, when there are natural oscillations of different magnification with a different area of the object's coverage, when some blocks independently oscillate, they unite into one system. Thirdly, the existence of walls with double reflecting properties, which changes the field of standing waves. Fourthly, the complex geometry of the object causes fields of standing waves, e is described by two wave numbers. Experimental data show that in the theory of buildings, it is necessary to move to the models of nested resonators, models of coupled resonators, and the verification of models should be entrusted to the standing wave method.

Reconstruction of precipitating electrons and three-dimensional structure of a pulsating auroral patch from monochromatic auroral images obtained from multiple observation points

Abstract: Abstract. In recent years, aurora observation networks using high-sensitivity cameras have been developed in the polar regions. These networks allow dimmer auroras, such as pulsating auroras (PsAs), to be observed with a high signal-to-noise ratio. We reconstructed the horizontal distribution of precipitating electrons using computed tomography with monochromatic PsA images obtained from three observation points. The three-dimensional distribution of the volume emission rate (VER) of the PsA was also reconstructed. The characteristic energy of the reconstructed precipitating electron flux ranged from 6 to 23 keV, and the peak altitude of the reconstructed VER ranged from 90 to 104 km. We evaluated the results using a model aurora and compared the model's electron density with the observed one. The electron density was reconstructed correctly to some extent, even after a decrease in PsA intensity. These results suggest that the horizontal distribution of precipitating electrons associated with PsAs can be effectively reconstructed from ground-based optical observations.

Depth Estimation and Ray Tracing Model Selection of Buried Utilities on Ground Penetrating Radar Data

Abstract: When assessing a target depth from a Ground Penetrating Radar (GPR) image, one typically assumes a certain wave propagation model as well as the model parameters (typically the dielectric of the medium). While much work has been conducted on the automatic inference of the model parameters, not much work has been performed testing the validity of the model itself. The work presented here closes this gap for a low-frequency GPR system (350 MHz center frequency). It compares the measurement, taken from known targets at known depths, with different ray propagation models. It also presents a novel method for efficiently estimating the depth of a target without using any knowledge of the medium's wave propagation speed, or even the time of the signal's emission from the transmitter (time zero). Experiments on 26 targets of varying depths showed an averaged estimation error of less than 0.5%, with a standard deviation of 3% using this robust and efficient method.

Alfvén waves: To the 80th anniversary of discovery

Abstract: The article is dedicated to the anniversary of the discovery of Alfvén waves. The concept of Alfvén waves has played an outstanding role in the formation and development of cosmic electrodynamics. A distinctive feature of Alfvén waves is that at each point in space the group velocity vector and the external magnetic field vector are collinear to each other. As a result, Alfvén waves can carry momentum, energy, and information over long distances. We briefly describe two Alfvén resonators, one of which is formed in the ionosphere, and the second presumably exists in Earth’s radiation belt. The existence of the ionospheric resonator is justified theoretically and confirmed by numerous observations. The second resonator is located between reflection points located high above Earth symmetrically with respect to the plane of the geomagnetic equator.