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.
The possible temperature influence on the microparticle concentration in the near-surface layer of the Earth is presented. As input data we used either temperature variation instrumental observations as well as less than 2.5 μm (PM2.5) microparticle mass concentrations in the subsurface layer of the atmosphere. The measurements were held during the summer period of 2021 and 2022 years in the midlatitude Mikhnevo Geophysical Observatory of IDG RAS. While data processing and analysis, a strong correlation between the daily mean temperature values and PM2.5 concentrations was established. The maximum value of the Pearson linear correlation coefficient between the considered values was obtained in July. A high correlation is observed both for individual monthly correlations and for summer periods in general.
The possible response of the electric field in the surface layer of the atmosphere to the magnetic storm of February 15, 2023 is analyzed. We used data from instrumental observations of the variations in the vertical component of the electric field at the Mikhnevo Geophysical Observatory of Sadovsky Institute of Geosphere Dynamics of Russian Academy of Sciences and at the geophysical observatory of the IMCES SB RAS, of the variations in geomagnetic variations at the Mikhnevo Geophysical Observatory of Sadovsky Institute of Geosphere Dynamics of Russian Academy of Sciences and at the Novosibirsk magnetic observatory. It is shown that the magnetic storm manifested itself in variations of the vertical component of the electric field strength, and the main variations of the electric field in the surface layer of the atmosphere were observed during the main phase of the magnetic storm.
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 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.
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.
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 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.
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.
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.
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.
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.
Using the results of geomagnetic monitoring at the Mikhnevo geophysical observatory and spectral analysis methods, the spectral harmonics of geomagnetic variations were studied in the period range from 12 to 17 days. We have highlighted: harmonics associated with a variation in solar activity; harmonics due to the modulation of shorter-period variations by the long-period ones; harmonics close to periods of tidal waves, and harmonics close to the period of the atmospheric planetary 16-day wave. Comparative analysis of the spectral composition in summer and winter for a period of low solar activity were carried out.
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.
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