V. A. Kharlamov

Astronomical and physical aspects of the Chelyabinsk event (February 15, 2013)

Various observational data including infrasound, seismic, optical (onboard) monitoring, ground video and photo records, and evidence from witnesses of the Chelyabinsk event on February 15, 2013, have been analyzed. The extensive material gathered has provided a base for investigations of the physical properties of the object, the results of which are discussed. A bolide light curve is constructed, which shows a multiplicity of flashes. Estimations of the energy of the meteoroid explosion, which took place in the atmosphere at an altitude of about 23 km, show evidence of the formation of a high-power shock wave equivalent to 300–500 kilotons of TNT. The object diameter corresponding to this energy falls within the range 16–19 m. The trajectory of the meteor is outlined. It is preliminarily concluded that the Chelyabinsk meteorite was a representative the Apollo asteroid family.

Effects of lunar-solar tides in the variations of geophysical fields at the boundary between the Earth’s crust and the atmosphere

Extraterrestrial forcing of natural environmental processes by gravitational interaction between the Sun, the Moon, and the Earth is considered. Based on the instrumental data, the main periodical components and cycles are identified in the time variations of some geophysical fields at the boundary between the Earth’s crust and the atmosphere. Correlation analysis shows that the lunar-solar tides are the key factor responsible for diurnal and quasi-biweekly variations in the ground electric field, radon emanation, water level in wells, and microseismic vibrations. The tidal influence on the various-scale movements of the blocks of the Earth’s crust is analyzed. In the context of the vertical, lateral, and rotational motion of crustal blocks, which is very important for the platforms, a new, precession-like type of displacements is revealed. These movements develop as a result of the nonsynchronous tidal responses of the block and the adjacent interblock gaps or tectonic structures whose strength and strain properties are different in different directions.

Radon emanation as an indicator of the intensity of Intergeospheric interactions at the Earth’s crust-atmosphere interface

The results of measurements of the volumetric activity of subsurface radon Rare given for several sections of the Earth’s crust located within the central part of the East European Platform. The influence of tectonic structures on the spatial zonality of radon emanation and the intensity of its temporal variations is shown. The temporal variations in radon emanation are characterized by periodicity with periods of approximately a day, as well as of 4, 14, and 29 days, and, as correlation analysis shows, they are determined by the cyclic recurrence of tidal deformations and by cyclonic processes in the atmosphere. The high correlation of the mean values of the volumetric activity of subsurface radon with the value of atmospheric pressure is established. The dependence of the volumetric activity of subsurface radon and its temporal variations on the depth within the range of depths 0.8–11.5 m is determined. As a result of laboratory experiments, the nonlinear nature of the dependence of radon emanation on the frequency of vibration action is established. For granites, the intensity of radon emanation is maximal at frequencies of 16 and 32 Hz. The results of complex measurements of the microseismic background and the volumetric activity of subsurface radon carried out in the region of the Nelidovo-Ryazan tectonic structure demonstrate the high correlation between the volumetric activity of subsurface radon and the relative amplitude of the quasi-monochromatic component of the microseismic background with a peak frequency of 16.5 Hz.

Response of the seismic background to geomagnetic variations

642 The interaction and transformation of geophysical fields in the surface regions of the Earth’s crust is of special interest for distinguishing the nature and mechanisms of intergeospheric interactions and determining the influence of the geophysical field on the environment [1, 2]. The field of natural seismic oscillations of the Earth’s crust reflecting the degree of stability of its specific parts (for example, active facture zones, mobility of the block system, etc.) has become one of the most important fields in the human engi neering activity that contains information about the time variability of the geodynamic state of the Earth’s crust [3, 4]. This is the reason why it is important to distinguish the possible links between the background seismic field and other geophysical fields necessary for recognition of the interaction and transformation mechanisms. In this work, we analyze the influence of pulse geomagnetic perturbations on the field of back ground seismic oscillations in the Earth’s crust. A quantitative relation between the amplitude of pulse geomagnetic variations and fluctuations in the velocity of oscillations in the Earth’s seismic background in specific conditions was obtained for the first time.

Precessional motions of structural blocks of the Earth’s crust

Instrumental observations revealed a new type of motion previously not described in the literature, the precessional motions in the structural blocks of the Earth’s crust. The precession-nutation motions are caused largely by a complex response of a structural block and the adjacent tectonic structure, acting as a discontinuous zone between blocks, to tidal deformation. Irregular precession with a period of about one day complicated by the half a day period nutation defines a complex loading pattern characteristic of the internal structure of faults adjacent to the block.

Tidal effects in geomagnetic variations

This paper reports the results of processing and analysis of geomagnetic variations, estimates of their spectra, and the first identified waves of lunar–solar tides on the geomagnetic variation envelopes in the circadian range and in the periods of 13.66 and 27.55 days. The specific features of the geomagnetic variation spectrum open up new possibilities for evaluation of the viscosity of the Earth’s outer core, description of the geomagnetic dynamo, development of new models of movement of the Earth’s inner core and the current system dynamics in the outer (liquid) core, and establishment of the general regularities controlling the energy exchange conditions in the geosphere.

Geophysical fields of a megalopolis

A description of the Center of Geophysical Monitoring for Systematic Investigation of Negative Consequences for the Human Environment and Infrastructure of the City of Moscow Resulting from Natural and Technogenic Factors, which is part of the Institute of Geosphere Dynamics of the Russian Academy of Sciences (IGD RAS), is presented. The results of synchronous observations of the seismic vibrations, electric and acoustic fields, and atmospheric meteoparameters performed at the Center and in the Mikhnevo Geophysical observatory of IGD RAS situated outside of the zone of the Moscow influence are examined. It is shown that the megalopolis influence consists of an increase in the amplitudes of the physical fields, a change in their spectral composition, and the violation of natural periodicities. A technogenic component that has a considerable impact on the natural physical processes in the surface atmosphere is an important factor that characterizes a megalopolis.

Results of instrumental observations of tidal wave propagation in the atmosphere

This paper presents the results of processing and analysis of acoustic waves in the surface layer of the atmosphere, registered at the Mikhnevo Geophysical Observatory, Institute of Geosphere Dynamics, Russian Academy of Sciences (IGD RAS). Using the autoregression model of digital series, the spectrum of acoustic oscillations was evaluated and the tidal waves in the envelopes of acoustic oscillations were distinguished. The tidal components with similar periods were separated using the method of extraction of harmonic components by using adaptive notch filters. The observed features of the spectrum of acoustic oscillations open up new opportunities for instrumental control over meteorological conditions and the establishment of general regularities controlling the regimes of energy-exchange processes in the Earth’s atmosphere.

Peculiarities of the seismic magnetic effect in the zone of fracture influence

In this paper we analyze the seismic magnetic effect and also the influence of the fracture zone on the spa tial distribution of geomagnetic variations in the sur face atmospheric layer caused by the propagation of seismic waves of various origin. We demonstrated for the first time on the basis of synchronous data of seis mic waves of different amplitudes and geomagnetic variations recorded in one of the regions of the central part of the East European Platform that the amplitude of the seismic magnetic effect is maximal in the frac ture zone and notably decreases with distance from the fracture zone according to the exponential law reach ing a constant value beginning from the distance equal to approximately three widths of the fracture zone.

Synchronous variations in the Earth’s magnetic field and groundwater level

427 The magnetic field of the Earth is characterized by both irregular and quasi periodical variations in response to the disturbing influence of internal and external sources. The periodicity of temporal geomag netic variations registered at the surface is determined both by a global component related to changes in the solar activity and its consequences (ionospheric and magnetospheric perturbations) and by a local compo nent that reflects variations in the electric and geome chanical properties of surface crustal layers, such as electric conductivity, medium structure, and its deflection mode [1–3]. The groundwater regime is an important factor responsible, primarily, for electric conductivity and the deflection mode of the geophys ical medium.