Meteoroid Explosion Research Articles

Assessment of Morelian Meteoroid Impact on Mexican Environment

Possible ionospheric effects of the Morelian meteoroid that passed and exploded over Mexico on 19 February 2020 (18 February 2020 local time) were estimated. The meteoroid trajectory, velocity and time of occurrence were calculated based on outdoor camera records. Modeling was used to estimate the meteoroid initial diameter, density, mass, velocity, energy and their change during its flight in the atmosphere. The ensemble of ionospheric scintillation indices calculated from the high-rate GNSS data and the filtered slant Total Electron Content data were used to reveal the presence of ionospheric disturbances generated by shock waves excited by the meteoroid flight and explosion. The first ionospheric responses to phenomena accompanying the meteoroid were detected (2.5–3.5) min after the explosion. The disturbances were attenuated quickly with distance from their source and were rarely recorded by GNSS receivers located more than 600 km from the meteoroid explosion site. The ionospheric disturbances of intermediate-scale, small-scale, shock-acoustic-wave-scale and sometimes medium-scale were revealed. The detected disturbances corresponded to the range of acoustic-gravity waves. An asymmetry of the disturbance manifestation in different directions was observed. The obtained results are in accordance with results of the observation of other meteoroids. Although the object was smaller and of less energy than other known meteoroids, it is an interesting case because, to the best of our knowledge, it isthe first known to us low-latitude meteoroid with the detected ionospheric effects.

Characteristics of Infrasonic Signals Generated by the Lipetsk Meteoroid: Statistical Analysis

The purpose of this paper is to construct basic correlation diagrams and plot the respective regression functions for the parameters of the infrasonic signals launched by the Lipetsk meteoroid. The celestial body that entered the Earth’s atmosphere at 01:16:20 UT on June 21, 2018, had the following initial parameters: 14.4 km/s speed, approximately 113 t mass, approximately 4 m size, and approximately 2.8 kt TNT kinetic energy. The infrasonic signals generated by the celestial body were observed on a global scale, and they were recorded by the International Monitoring System (IMS) set up by the Comprehensive Nuclear-Test-Ban Treaty Organization’s International Monitoring System (CTBTO). For data processing, techniques of mathematical statistics have been invoked. The basic results of the study are as follows. The infrasonic signal exhibits a linear dependence of the infrasonic signal time delay on the horizontal distance from the meteoroid explosion epicenter, and the signal celerity averaged over all propagation paths is estimated to be approximately 304–305 m/s. The infrasonic signal celerity first shows a rapid enough decrease with distance, but over the 4.5–8.66-Mm distance range exhibits fluctuations at approximately 302 m/s. The duration of the infrasonic signal shows a linear decrease with distance, and the signal duration dispersion is insignificant in the 5–8 Mm distance range. The mean periods of the infrasonic signal, independent of distance and averaged over various regression functions, are estimated to be 6.28 ± 0.98 s and 6.14 ± 0.76 s. The mean of the initial kinetic energy estimated using the oscillation period of the infrasonic signal is 2.26–2.43 kt TNT, which differs insignificantly from the NASA estimates (2.8 kt TNT). The approximation for the dependence of celerity versus sine of the back-azimuth angle of arrival shows that the corrected value of the celerity is approximately 300 m/s, and the mean of the troposphere-stratosphere wind is approximately 25–31 m/s. Analysis of the correlation diagrams has shown that a steady statistical link exists between the true and observed back-azimuth angles of infrasound sources. It is noted that the level of fluctuations in the azimuth tends to increase with distance.

Ionospheric effects of the Kamchatka meteoroid: Results from multipath oblique sounding

This paper presents the results of radio observations of ionospheric disturbances associated with the fall of a meteoroid (unique in its initial energy of 173 kt TNT equivalent) off the east coast of the Kamchatka Peninsula on 18 December 2018. The ionospheric disturbances were measured with the multipath radio system designed for oblique sounding and located at the Harbin Engineering University campus, the People's Republic of China (PRC). The main results are as follows. The ionospheric disturbances following the Kamchatka meteoroid entry and explosion have been detected in the temporal variations in the Doppler spectra and signal amplitudes observed over six oblique propagation paths. The possible disturbances have 2–3 groups of time delays. Depending on the distance between the terminal detonation point and the propagation path midpoint, these time delays fall into the 24–43-min, 93–136-min and 141–183-min time intervals, corresponding to the apparent speeds of 1.9–2.9 km/s, 620–770 m/s and 310–500 m/s, respectively. The disturbances with the apparent speeds of hundreds of meters per second and periods of about 10–15 min are transported by atmospheric gravity waves. The disturbances propagating with the 1.9–2.9-km/s apparent speeds could be caused by ionospheric processes due to the seismic waves generated by the meteoroid explosion.

Analysis of Ionospheric Disturbances Caused by the 2018 Bering Sea Meteor Explosion Based on GPS Observations.

The Bering Sea meteor explosion that occurred on 18 December 2018 provides a good opportunity to study the ionospheric disturbances caused by meteor explosions. Total electron content (TEC) is the core parameter of ionospheric analysis. TEC and its changes can be accurately estimated based on the Global Positioning System (GPS). TID is detected in time and frequency domain based on power spectrum and Butterworth filtering method. By analyzing the waveform, period, wavelength, propagation speed and space-time distribution of TID, the location of the TID source is determined, and the process of TID formation and propagation is understood. The TID caused by meteor explosions has significant anisotropy characteristic. Two types of TID were found. For the first type, the average horizontal propagation velocity is 250.22 ± 5.98 m/s, the wavelength is ~135–240 km, the average period is about 12 min, and the propagation distance is less than 1400 km. About 8 min after the meteor explosion, the first type of TID source formed and propagated radially at the velocity of 250.22 ± 5.98 m/s. For the second type, the propagation velocity is ~434.02 m/s. According to the waveform, period, wavelength and propagation velocity of the TID, it is diagnosed to be the midscale traveling ionospheric disturbances (MSTID). Based on the characteristics of TID, we infer that the TID is excited by the gravity waves generated by the meteor explosion, which is in accordance with the propagation law of gravity waves in the ionosphere. And it is estimated that the average velocity of the up-going gravity waves is about 464.58 m/s. A simple model was established to explain the formation and the propagation of this TID, and to verify the characteristics of the TID propagation caused by nuclear explosion, earthquake, tsunami, and Chelyabinsk meteorite blast. It is estimated that the position of the TID source is consistent with the meteor explosion point, which further indicates that the TID is caused by the meteor explosion and propagates radially.

Effects of the Lipetsk Meteoroid in the Geomagnetic Field

Observational data from the Kiev (Ukraine), Borok, St. Petersburg, Hel (Poland), Arti, Novosibirsk, Almaty (Kazakhstan), and Irkutsk magnetic observatories are used to analyze the temporal variations of the geomagnetic field components on day of the Lipetsk meteoroid fall (June 21, 2018) and on reference days (June 20 and 22, 2018). The distance R from the place of explosion-like energy release by the meteoroid to the observatories varied from 0.584 to 4.324 Mm. The passage of the Lipetsk meteoroid in the magnetosphere and atmosphere turned out to be accompanied by variations mainly in the H component of the geomagnetic field. The magnetic effect was observed 54–56 min before the meteoroid explosion; the amplitude and duration of geomagnetic field disturbances did not exceed 0.5–1 nT and ~25 min, respectively. After a meteoroid explosion with a delay of 6–8 to 13–14 min for R from 0.584 to 4.324 Mm, alternating bursts (first, positive and, then, negative) in the H component. The burst amplitude decreased from 3.75 to 1.1 nT with an increase in R from 0.584 to 4.324 Mm. In this case, the duration of the magnetic effect varied for all distances within 15–20 min. Theoretical models of the observed magnetic effects are proposed, and their theoretical estimates are made. The results of observations and estimates are in good agreement with each other.

Geomagnetic Variations Caused by the Lipetsk Meteoroid’s Passage and Explosion: Measurement Results

The magnetic effect of meteors was first observed and theoretically explained back in the middle of the 20th century. The mechanisms for the magnetic effect of large celestial bodies (1–10 m and more) fundamentally differ from the mechanisms of geomagnetic field disturbances caused by meteors at ionospheric heights. The passage of a large meteoroid through the atmosphere and its explosion are accompanied by the generation of a powerful shock wave and the formation of a plume, which result in a geomagnetic effect. To the present day, researchers are divided on the main mechanism for the geomagnetic effect of large meteoroids. The Tunguska and Chelyabinsk meteoroid measurements are available for studies. In the case of the Chelyabinsk meteoroid, the variations in the geomagnetic field are detected and explained both prior to and after the explosion of this celestial body. Analyzing observations of the passage of any large enough celestial body is of considerable theoretical and practical interest. The purposes of this study are to present the analysis of magnetic field variations that arose as a result of the Lipetsk meteoroid passage through the Earth’s magnetosphere and atmosphere and to estimate and discuss the magnetic effect and its mechanisms. The fall rate of such meteoroids is 0.68 yr–1. Using the data provided by the Magnetic Observatory of Karazin Kharkiv National University (Kharkiv, Ukraine), the temporal variations in the horizontal components of the geomagnetic field on June 21, 2018, (the day of the Lipetsk meteoroid passage) and on June 20 and 22, 2018, (the reference days) have been analyzed. The meteoroid’s initial speed was 14.4 km/s, the initial mass was 113 t, and the initial size equaled approximately 4 m. The distance from the observatories to the site where the meteoroid explosion-like release of energy occurred was 360 km. The passage of the Lipetsk meteoroid in the magnetosphere and atmosphere has been shown to be accompanied by alternating variations in the geomagnetic field components. The magnetic effect of the magnetosphere was observed 54–56 min before the meteoroid explosion; the amplitude of the disturbance in the geomagnetic field did not exceed 0.5–1 nT, and the duration was 15–20 min. Alternating spikes (first positive, then negative) in the H and D component level were observed after the meteoroid explosion with a ∼6-min delay. The spike amplitude was ∼1.2–1.5 nT, while the duration of the magnetic effect from the ionosphere reached tens of minutes. The models for the magnetic effects observed are suggested and theoretical estimates are performed. The observations and the estimates are in good agreement.

Ionospheric Effects of the Lipetsk Meteoroid

The time variations in the Doppler spectra at frequencies of 3.2 and 4.2 MHz on the day of fall of the Lipetsk meteoroid (near Lipetsk town, Russia) on June 21, 2018, and on the adjacent control days are analyzed with vertical Doppler sounding radar located near Kharkov (Ukraine). Two types of effects were observed in the ionospheric F region after the meteoroid explosion. The first was a “decomposition” of the Doppler spectra approximately 11 min after the explosion and lasted ~16–17 min. Quasi-periodic variations in the Doppler frequency shift with a variable period of 10–20 min and amplitudes of 0.11 and 0.19 Hz for 3.2 and 4.2 MHz, respectively, were registered 31–33 min after explosion. The duration of this process was ~120 min. The physical mechanisms of ionospheric disturbances observed after the meteoroid explosion are discussed.

Infrasonic waves and assessment of energy of explosion of Beringovomorsky meteoroid on December 19, 2018

On December 18, 2018 at 23:48 UTC in the Earths atmosphere, at the height of 25,6 km over the Bering sea, destruction of a meteoroid with formation of a shockwave occurred. The mass of the Beringovomorsky meteoroid is estimated as 1600 tons, and its diameter is estimated as 9-14 meters. If assessment is right, then for the last 30 years it was the second in energy explosion of a space body in the Earths atmosphere. The nearest to the epicenter of meteoroid explosion station of the international system of infrasonic monitoring (IS44 station) is located on the Kamchatka peninsula at a distance of 1024 km. At IS44 station, an infrasonic signal from destruction of a meteoroid was registered. In this paper, the results of analysis of the infrasonic signal registered by IS44 are represented and the estimation of energy of this event is carried out.

Infrasonic Waves and Assessment of the Explosion Energy of the Bering Sea Meteoroid on December 19, 2018

On December 18, 2018, at 23:48 UTC a meteoroid exploded in the Earth’s atmosphere, at a height of 25.6 km over the Bering Sea, causing a shockwave. The mass of the Bering Sea meteoroid was estimated at 1600 tons, and its diameter, at 9–14 meters. If these assessments are correct, it was the second largest explosion of a space body in the Earth’s atmosphere for the past 30 years. Station IS44 of the international system of infrasonic monitoring, nearest to the epicenter of meteoroid explosion, is located on the peninsula of Kamchatka at a distance of 1024 km. At the IS44 station, an infrasonic signal from the meteoroid explosion was recorded. This paper presents the analysis of this infrasonic signal and an assessment of the energy of this event.

Physical Effects of the Lipetsk Meteoroid: 3

Comprehensive modeling studies of the processes induced in all geospheres by the passage and explosion of the meteoroid near the city of Lipetsk (Russia) on June 21, 2018, have been conducted. Magnetic, electric, electromagnetic, ionospheric, and seismic effects, as well as the effects of acoustic-gravity waves have been estimated. The magnetic effect of turbulence has been shown to be insignificant. The magnetic effect of the ionospheric currents and the current in the wake of the meteoroid could be substantial (~1 nT). Under the action of an external electric field, a transient current pulse with the strength of current up to 104 A could occur. The electrostatic effect could be accompanied by the accumulation of an electric charge of 1 mC producing the electric field intensity of 0.01–1 MV/m. The flow of the electric current in the wake of the meteoroid could result in the generation of an electromagnetic pulse in the 40–80 kHz band with the electric field intensity of 1–10 V/m. The electromagnetic effect of infrasound has been determined to be significant (1–10 V/m and 1–10 nT). The absorption of the shock wave at ionospheric dynamo region altitudes (100–150 km) could generate secondary atmospheric gravity waves with the 0.1–1 relative amplitude. The passage of the meteoroid acted to produce a plasma wake and noticeable disturbance not only in the lower but also in the upper atmosphere in the range of no less than 1000 km. The possibility of occurrence of the electrophonic effect, the generation of the ion and magnetic sound by infrasound, and the generation of gradient-drift and drift-dissipative instabilities are discussed. A conclusion is drawn that magnetic, electric, and electromagnetic effects dealt with in this paper significantly fill in the gaps in the theory of physical effects produced by meteoroids in the Earth–atmosphere–ionosphere–magnetosphere system. The magnitudes of magnetic, electric, electromagnetic, ionospheric, and acoustic effects were significant. The magnitude of the earthquake caused by the meteoroid explosion did not exceeded 1.7. The mean rate of the fall of celestial bodies similar to the Lipetsk meteoroid is equal to 0.68 yr–1.

Parameters of Acoustic Signals Generated by the Atmospheric Meteoroid Explosion over Romania on January 7, 2015

System spectral analysis of temporal variations in the level of acoustic signals recorded at a number of European infrasound stations is carried out. The prevailing periods that varied within 3–5 s are found. Initial kinetic and acoustic energies of the Romanian meteoroid and infrasound parameters are calculated: celerity (280 m/s), acoustic efficiency, and stratospheric wind velocity (about 20 m/s). Parameters of cylindrical and explosive shock waves are found: duration, characteristic size, and amplitude. The dependence of the attenuation of infrasonic waves on distance is estimated. The results of the estimates are in good agreement with the results of the observations.

Simulating the Propagation of Infrasonic Waves and Estimating the Energy of the Chelyabinsk Meteoroid Explosion Observed on February 15, 2013

Results obtained from simulating the propagation of infrasonic waves from the Chelyabinsk meteoroid explosion observed on February 15, 2013, are given. The pseudodifferential parabolic equation (PDPE) method has been used for calculations. Data on infrasonic waves recorded at the IS31 station (Aktyubinsk, Kazakhstan), located 542.7 km from the likely location of the explosion, have been analyzed. Six infrasonic arrivals (isolated clearly defined pulse signals) were recorded. It is shown that the first “fast” arrival (F) corresponds to the propagation of infrasound in a surface acoustic waveguide. The rest of the arrivals (T1–T5) are thermospheric. The agreement between the results of calculations based on the PDPE method and experimental data is satisfactory. The energy E of the explosion has been estimated using two methods. One of these methods is based on the law of conservation of the acoustic pulse I, which is a product of the wave profile area S/2 of the signal under analysis and the distance to its source E I [kt] = 1.38 × 10–10 (I [kg/s])1.482. The other method is based on the relation between the energy of explosion and the dominant period T of recorded signal E T [kt] = 1.02 × (T [s]2/σ)3/2, where σ is the dimensionless distance determining the degree of nonlinear effects during the propagation of sound along ray trajectories. According to the data, the explosion energy E I,T ranges from 1.87 to 32 kt TNT.

Magnetic and Ionospheric Effects of a Meteoroid Plume

This paper is concerned with the study of the possibility of products of a meteoroid explosion in the atmosphere (meteoroid plume) to reach ionospheric altitudes. It has been shown that, in the case of meter-sized or larger space bodies entering the atmosphere, the plume is able to reach the lower ionosphere. The plume can be one of the sources of the formation of nacreous and noctilucent clouds. The aerosols ejected by the plume to lower ionospheric altitudes can lead to the formation of dust plasma, significantly changing the electrodynamic properties of the medium. The motion of the plume with a velocity of ~1 km/s is accompanied by the generation of a ballistic shock with a radius of 1–10 km. The relative excess pressure in the shock front can cause relative disturbances in the electron content at the altitudes of D, E, and F1 layers by ~10–100%. The geomagnetic effect of the plume and ballistic shock can reach ~1–10 nT.

Infrasound emission of the Chelyabinsk meteoroid

Data from observing the infrasound effects induced by the Chelyabinsk meteoroid impact of February 15, 2013 are presented. Similar infrasound effects registered earlier and ways of interpreting them are described. The characteristics of the infrasound station of the Institute of Solar and Terrestrial Physics, Russian Academy of Sciences, Siberian Branch, Irkutsk, which registered the effect of the meteoroid explosion in the atmosphere, are also described. The shape of the infrasound signal from the Chelyabinsk meteoroid is presented and its parameters are discussed.

Ionosonde observations of ionospheric disturbances due to the 15 February 2013 Chelyabinsk meteor explosion

AbstractWe report the results of our investigations on the potential ionospheric effects caused by the 15 February 2013 Chelyabinsk meteor explosion. We used the data from a number of digisonde stations located in Europe and Russia to detect the traveling ionospheric disturbances (TIDs) likely to have been caused by the meteor explosion. We found that certain characteristic signatures of the TIDs can be identified in individual ionogram records, mostly in the form of Y‐forking/splitting of the ionogram traces. Based on the arrival times of the disturbances, we have inferred the overall propagation speed of the TIDs from Chelyabinsk to be 171 ± 14 m/s.

Nuclear test monitoring system detected meteor explosion over Russia

Sound waves from the Chelyabinsk meteor, which exploded over Russia on 15 February 2013, were detected by 20 infrasound stations that are part of the international monitoring system operated by the Comprehensive Nuclear‐Test‐Ban Treaty Organization (CTBTO). The fireball was the most energetic event observed since the 1908 Tunguska meteorite impact and is the most energetic event detected by the CTBTO network.

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.

Fireball on 6 July 2002 over the Mediterranean Sea is a fragment of the comet's nucleus

AbstractToday has been known for a considerable number of cases, the explosion of large meteoroids in Earth's atmosphere. This is confirmed by the data of registrations of fireballs by devices and the results of measurements in the atmosphere of bright light flashes by photodiodes Corporation “Sandia Laboratories", which were installed on geostationary satellites of the United States, and also by data of measurements of acoustic-gravitational waves from the thermal explosions of meteoroids [ReVelle D.O. Historical detection of atmospheric impacts by large bolides using acoustic-gravity waves, Near-Earth Objects, Ed. Remo J. Annals of the New York Academy of Sciences 882, 284-302, 1997]. The work [Brown P., Spalding R.E., ReVelle D.O. et al. The flux of small near-Earth objects colliding with the Earth, Nature 420, 314-316, 2002.] shows the results of processing the observations of flashes of large meteoroids in Earth's atmosphere, obtained with the help of geostationary satellites of the United States. Over 8.5 years (from February 1994 to September 2002) 300 such events were registered. On July 6, 2002 r over the Mediterranean Sea a bright fireball was registered. The energy of the meteoroid explosion that caused the phenomenon of the car, was 26 kilotons of TNT [Brown et al., 2002]. We believe that this energy refers to the height of the full bracking of the meteoroid. At a speed of 20.3 km/s adopted by the authors, body mass at this height is 5 × 108 g, and when entering the Earth's atmosphere, it was about 7 × 108 g. Based on the obtained values of the mass, we conclude that the exploded meteoroid, causing a phenomenon of the fireball was a fragment of the comet nucleus. In processing the density of the body were taken 1 g/cm3 and the initial velocity (~30 km/s).

The Sounds of Waves and Meteors

GEOPHYSICS The seismology division of the Royal Netherlands Meteorological Institute operates an array of micro-barometers that detects low-frequency (0.002 to 40 hertz) sound waves traveling through the atmosphere. This frequency range covers infrasonic disturbances inaudible to humans, such as distant nuclear explosions, and similar arrays are being installed worldwide as part of the Comprehensive Nuclear Test Ban Treaty. The Deelen array covers about 1.5 square kilometers and incorporates five porous hoses attached to each micro-barometer to reduce noise from atmospheric wind. Evers and Haak report detection on 8 November 1999 of a discrete 0.15 Hz component along with a continuous 0.19 Hz component. The 0.15 Hz signal came from the northeast, and the source was identified as a meteor explosion in the atmosphere over northern Germany, as confirmed by eyewitness accounts and photographs. The higher frequency signal came from the northwest (the northern Atlantic) and was associated with standing ocean waves coupled to the atmosphere (these sounds are called microbaroms). The authors estimated that the meteor explosion occurred at about 15 km in altitude and released energy equivalent to about 1.5 kilotons of TNT, within the range for nuclear explosions. — LR Geophys. Res. Lett. 28 , 41 (2001).

Ozone, dust, smoke and humidity in nuclear winter

Recent correspondence on nuclear winter is commented on. Reasons are given for why the Tunguska meteor explosion may not be useful in calibrating the effects of a major nuclear exchange. The relationship between the optical depth of an aerosol cloud, the composition of the cloud, and its effect on sunlight intensity and climate are clarified. The significance of the Tambora eruption of 1815 and of historical fires for the nuclear winter theory are briefly discussed. The dispersion of smoke plumes from large fires is addressed, and water condensation and smoke scavenging are considered.