A numerical model is proposed for the influence of a volcanic eruption accompanied by an intense vertical flow of an ash-gas mixture on the disturbance of the geomagnetic field. As the main mechanism of the magnetic effect, the impact on the epicentral region of the Earth's ionosphere of wave atmospheric disturbances caused by volcanic activity is considered. The estimates made on the basis of the proposed model on the example of the eruption of the Raikoke volcano on June 21, 2019 (Kuriles) are consistent with the results of instrumental observations.
Atmospheric effects caused by catastrophic earthquakes in Turkey on February 6, 2023 are analyzed. We used the data of instrumental observations of microbaric variations in the atmosphere and electric field variations performed at the IDG RAS, as well as data obtained by a number of magnetic observatories of the INTERNAGNET network and ionospheric sounding stations of the Athens National Observatory. It is shown that the earthquakes were accompanied by infrasound signals, variations of the magnetic and electric fields at considerable distances from the source, as well as changes in the critical frequency of the ionosphere F2-layer.
Using the results of instrumental observations, acoustic, electrical and magnetic effects caused by the explosive destruction of a bolide on 10/16/2023 near Tomsk were established. It is shown that the effects have a non-local character and are recorded at a significant epicentral distance from the point of explosion of the bolide both during the event itself and during the arrival of the infrasound signal at the point of instrumental observations. Using an approach based on the properties of the infrasound signal not to change the characteristic frequency with distance, the energy of the source was estimated to be 3.7.1013 J.
Based on the analysis of the results of instrumental observations, it is shown that the explosion of the volcano caused a series of wave disturbances in the atmosphere, as well as variations in the electric and magnetic fields of the Earth at significant epicentral distances. Atmospheric disturbances were recorded in the form of Lamb waves with a source at the epicenter of the explosion, as well as a virtual source located at the antipode, and the formation of which is associated with the convergence and summation of signals propagating along the Earth's sphere. In addition to the primary waves, secondary and tertiary waves were registered, which were formed as a result of the repeated passage of the signal caused by the explosion around the Earth's sphere. The source energy has been estimated.
Using the results of instrumental observations, the acoustic, electrical and magnetic effects of the explosive destruction of the bolide on November 17, 2021 in the region of Izhevsk was established. It was found that the effects are non-local in nature and were registered at a significant epicentral distances from the explosion. It is noted that variations in the magnetic field were observed both during the fall of the bolide and during the arrival of the atmospheric signal at the registration point. Based on the characteristic frequency of the atmospheric signal, the bolide explosion energy was estimated, which was 9.4•1010 J.
Based on the results of the analysis of coordinate data obtained as a result of constant registration at the Mikhnevo Geophysical Observatory of IDG RAS using a stationary GPS receiver, it is shown that during periods of strong geomagnetic disturbances, the positioning error increases significantly. It is shown that the variations of the positioning error in magnetic storms are characterized by a well-defined periodicity with a period of about 3 minutes. In this case, the maximum error is contained in the range of 4 ‒ 26 m and practically does not depend on the amplitude of the geomagnetic variation. The data obtained in this research allow us to consider the variations of the positioning error as an indicator of the disturbed state of the ionosphere and atmosphere during magnetic storms, as well as as a parameter that characterizes the degree of disturbance of the environment and the conditions for the propagation of a high-frequency electro-magnetic GPS signal in it.
Based on the results of instrumental observations, it is shown that magnetic storms cause microbaric variations in atmospheric pressure with an amplitude of 2 to 20 Pa in the range of periods of 20 ‒ 80 min, as well as with frequencies close to the Brent-Väisälä frequency. The spectrum of microbaric variations during magnetic storms contains several quasiharmonic components.
The analysis of the results of instrumental observations of variations in geophysical fields during hurricanes in Moscow, recorded for the period 2009 ‒ 2017, is presented. The digital series of the vertical component of the electric field strength, micropulsations of atmospheric pressure and the amplitude of seismic noise were analyzed.
The results of instrumental observations of variations in the electrical characteristics of the near-surface atmosphere during 58 magnetic storms are analyzed. It is shown that geomagnetic disturbances with a station index of magnetic activity K ≥ 5 (Mikhnevo Geophysical Observatory of IDG RAS) are accompanied by characteristic variations in the vertical components of the electric field and atmospheric current. The amplitude of the electric field variations is characterized by a value of 5 ‒ 20 V/m, the atmospheric current with an amplitude of up to 4 ‒ 6 pA/m2.
On the example of the Chelyabinsk (February 15, 2013) and Lipetsk (June 21, 2018) events, the geomagnetic variations accompanying the fall of meteorites in the Earth's atmosphere are considered. Using the data of instrumental observations carried out at a number of magnetic observatories of the International INTERMAGNET Network and at the Mikhnevo Geophysical Observatory of Sadovsky Institute of Geosphere Dynamics of Russian Academy of Sciences it is shown that, in general, the fall of meteorites causes a change in the modulus of the magnetic induction vector by up to ~ 3.5 nT, regardless of the distance to the place of impact of the cosmic body. In this case, the horizontal components of the magnetic induction decrease in a bay-like character with an amplitude of up to ~ 8 nT. The geomagnetic effect of meteorite impacts is observed at distances of up to 2700 km. The dependence of the duration of the induced variations of the modulus of the magnetic induction vector on the distance is proposed.
Infrasound waves generated by auroras are usually recorded at high latitudes during periods of high geomagnetic activity. These waves are often characterized by high apparent velocities (usually from 400 to 1000 m/s), which means that their source locates at a high altitude. Currently, the relation between the atmosphere electric-field variations and infrasound in the near-surface atmospheric layer during magnetospheric substorms is determined. However, for the full-scale analysis of the said interaction, we must have a predictive picture of the infrasonic atmospheric response, which raises the need for its modeling.
The results of instrumental observations of variations in the vertical component of the electric field strength and atmospheric current caused by strong earthquakes are analyzed. It is shown that strong earthquakes cause alternating variations of the electric field, or bay-shaped variations of the positive or negative sign at significant distances from the event center. Earthquakes are accompanied by variations in the atmospheric current in the form of alternating variations.
Acoustic effects associated with volcanic eruptions are considered. The phenomenological classification of wave disturbances caused by volcanoes in the atmosphere is given. Wave disturbances classes that are characteristic of different types of volcanic activity are discussed. The basic mechanisms for generating low-frequency infrasound waves during large explosive eruptions of explosive type are described. As an example, acoustic effects caused by the eruption of the Stromboli volcano in July ‒ August 2019 are presented and discussed.
Based on the analysis of instrumental observation data, it is shown that large fires on gas pipelines manifest themselves in local variations in the amplitude of acoustic vibrations. The formation of a highly heated convective stream of gaseous products over a stationary combustion center provides an intensive supply of cold air into it. In this case, the formation of pressure and temperature gradients near the flame leads to the formation of vortex structures in the atmosphere and the generation of infrasound. An example of a severe fire on a gas pipeline in Moscow on May 10, 2009 is considered.
Using the results of instrumental observations, it was shown that the explosion of the Stromboli volcano on July 3, 2019, caused variations in the atmospheric electric field and the amplitude of the atmospheric current at the Mikhnevo Geophysical Observatory and at the Center for Geophysical Monitoring in Moscow of IDG RAS located at distances of ~ 2450 km and ~ 2500 km from the source, respectively. Anomalous variations in the electric field were also recorded during the period of arrival of the acoustic signal at electric monitoring points.
We consider the disturbances of the magnetic field, electrical characteristics, and microbaric variations in the surface atmosphere caused by a strong earthquake that occurred in Turkey on January 24, 2020. The effects were recorded at the Mikhnevo observatory of Sadovsky Institute of Geosphere Dynamics of Russian Academy of Sciences which is located at distance of ~ 1900 km from the earthquake focus. It is shown that the acoustic effects accompanying the earthquake are caused by two sources: acoustic signal produced by arrival of seismic waves and acoustic signal propagating in the stratospheric waveguide. Using the data of the Mikhnevo observatory, we present the amplitudes of the induced variations in the electric field and atmospheric current. Also geomagnetic variations at different distances from the earthquake focus are presented.
Based on the analysis of instrumental observational data, it was shown that large fires manifest themselves in local variations of the electric field and the amplitude of acoustic vibrations. Above the fire area, the formation of the zone with altered thermodynamic characteristics causes the formation of acoustic-gravitational waves with a Brent-Väisälä frequency during the most intense burning. The examples of the strong fires in Moscow are considered.
The paper presents the results of experimental studies of the influence of the level of tonal acoustic noise on the times of simple human reactions, such as a simple auditory-motor reaction, a simple visual-motor reaction, a simple tactile-motor reaction, as well as a detection reaction. Experimental studies have shown that during the action of tonal acoustic noise with a frequency of 100 Hz, the subjects experienced an increase in the times of all the simple reactions being analyzed. The effect of tonal noise with a frequency of 100 Hz on the detection response is less pronounced.
A new approach to the prevention of atmospheric hazard in the form of hurricanes, squalls and heavy thunderstorms has been proposed. Anomalous variations of electric and magnetic fields, atmospheric current, as well as increased amplitudes of seismic vibrations and micropulsations of atmospheric pressure, recorded 1–8 hours before the arrival and the onset of the most intense manifestations of these phenomena, are considered as a complex prognostic sign. The obtained data can contribute to improving the reliability of the short-term forecast, as well as being of interest for the development of measures to prevent the negative and catastrophic consequences of strong atmospheric disturbances.
It describes new approach to assessment of energy sources of infrasound perturbations by spectrum of fluctuations in atmospheric pressure given stratigraphy of the atmosphere. It offers phenomenological model of spread of infrasound in standard atmosphere based on data of instrumental observations made during studying infrasound signals from powerful explosive atmospheric sources. There has been developed technique for assessment of energy which uses integral dependence of energy on power spectrum. Obtained results are consistent with known researches data.
Analysis of microbaric variations and variations of the electric field during atmosphere strong disturbances were carried out on the base of the data of instrumental registrations obtained in the geophysical observatory "Mikhnevo" of the Institute of Geospheres Dynamics of the Russian Academy of Sciences (IGD RAS). It is shown the hurricanes and storms are accompanied by high-amplitude variations of acoustic and electrical fields. Amplitudes of variations of these fields increase in a several hours before front arrival. This fact in the aggregate with meteorological parameters could be considered as a predicted indication of approaching hurricane or storms. It is determined that thundery front arrival is forestalled by long period electric field variations, internal gravity waves and increased acoustic impedance. Regularities, which were determined resulting from investigations, could be raise of forecast reliability and efficiency.
Given are results of analysis of data obtained by instrumental observations of infrasound vibrations performed in the area of Leninsky Avenue, Moscow. It was found that most intensive sources of infrasound are traffic lights and crossroads. Article illustrates difference in amplitude and spectral characteristics of infrasound depending on traffic flow regime. It contains date evidencing relation of infrasound noise with avenue load.
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