scholarly journals Dirty thunderstorms caused by volcano explosive eruptions in Kamchatka by the data of electromagnetic radiation

2021 ◽  
Vol 946 (1) ◽  
pp. 012015
Author(s):  
E I Malkin ◽  
N V Cherneva ◽  
P P Firstov ◽  
G I Druzhin ◽  
D V Sannikov
Keyword(s):  
Electromagnetic Radiation ◽  
Kamchatka Peninsula ◽  
Thunderstorm Activity ◽  
Cloud Formation ◽  
Explosive Eruptions ◽  
Second Stage ◽  
Direction Finder ◽  
Eruptive Column ◽  
Radio Equipment ◽  
Gas Cloud

Abstract During volcano eruptions, so called dirty thunderstorms are the sources of electromagnetic radiation. They are caused by ash-gas clouds formed during explosive eruptions. Thunderstorm activity in an ash-gas cloud during volcano eruption is monitored by radio equipment. The VLF direction finder, located at Paratunka, monitors thunderstorm activity in the region of Kamchatka Peninsula including dirty thunderstorms accompanying explosive eruptions of Shiveluch and Bezymyanniy volcanoes. In the paper, we analyze records of electromagnetic radiation associated with dirty thunderstorms occurring during volcano eruptions from 2017 to 2020. During that period 24 eruptions of Shiveluch volcano and 5 eruptions of Bezymyanniy volcano occurred. Seventeen and three of them, respectively, caused dirty thunderstorms. Two-stage scenario of development is typical for all the dirty thunderstorms. The first stage lasts for 5–7 minutes and accompanies eruptive column development. However, if the eruption begins according to a smooth scenario, the first stage may be weak. The second stage lasts for 20–80 minutes and is associated with eruptive cloud formation and propagation. The intensity of this dirty thunderstorm stage depends on eruption power as well as on the interaction of an eruptive cloud during its propagation with the clouds of meteorological origin. Based on the obtained data, that is indicated by the increase of cloud-to-cloud stroke number.

scholarly journals Principles of Creation of Local Network for Lightning Discharge Observations on Active Volcanoes of Kamchatka Peninsula

2019 ◽  
Vol 127 ◽  
pp. 02021
Author(s):  
Evgeniy Malkin ◽  
Gennadiy Druzhin ◽  
Pavel Firstov ◽  
Nina Cherneva ◽  
Vladimir Uvarov ◽  
...  
Keyword(s):  
Electromagnetic Radiation ◽  
Lightning Discharge ◽  
Kamchatka Peninsula ◽  
Thunderstorm Activity ◽  
Local Network ◽  
Auxiliary Equipment ◽  
Electric Field Sensors ◽  
Radiation Sources ◽  
Recorded Data ◽  
Volcanic Lightning

To investigate the thunderstorm activity according to electromagnetic radiation recorded data, it is necessary to create a local network which will be located near the Klyuchevskaya Sopka, Shiveluch and Tolbachik volcanoes. VLF direction finders, electric field sensors, synchronization system, auxiliary equipment will be installed at observation points. Based on the analysis of waveforms and spectral-temporal characteristics, the locations of radiation sources, their belonging to a certain class will be determined. The parameters, by which volcanic lightning differs from ordinary ones, will be determined. Examples of electromagnetic radiation occurring near the Shiveluch volcano are given. The information can be further used to monitor thunderstorm and volcanic activities.**

scholarly journals Holocene Key-Marker Tephra Layers in Kamchatka, Russia

1997 ◽  
Vol 47 (2) ◽  
pp. 125-139 ◽  
Author(s):  
Olga A. Braitseva ◽  
Vera V. Ponomareva ◽  
Leopold D. Sulerzhitsky ◽  
Ivan V. Melekestsev ◽  
John Bailey
Keyword(s):  
Grain Size ◽  
Size Distribution ◽  
Mineral Composition ◽  
Kamchatka Peninsula ◽  
Explosive Eruptions ◽  
Shiveluch Volcano ◽  
Stratigraphic Position ◽  
Tephra Layers ◽  
Characteristic Features ◽  
Important Marker

Detailed tephrochronological studies in Kamchatka Peninsula, Russia, permitted documentation of 24 Holocene key-marker tephra layers related to the largest explosive eruptions from 11 volcanic centers. Each layer was traced for tens to hundreds of kilometers away from the source volcano; its stratigraphic position, area of dispersal, age, characteristic features of grain-size distribution, and chemical and mineral composition confirmed its identification. The most important marker tephra horizons covering a large part of the peninsula are (from north to south; ages given in14C yr B.P.) SH2(≈1000 yr B.P.) and SH3(≈1400 yr B.P.) from Shiveluch volcano; KZ (≈7500 yr B.P.) from Kizimen volcano; KRM (≈7900 yr B.P.) from Karymsky caldera; KHG (≈7000 yr B.P.) from Khangar volcano; AV1(≈3500 yr B.P.), AV2(≈4000 yr B.P.), AV4(≈5500 yr B.P.), and AV5(≈5600 yr B.P.) from Avachinsky volcano; OP (≈1500 yr B.P.) from the Baraniy Amfiteatr crater at Opala volcano; KHD (≈2800 yr B.P.) from the “maar” at Khodutka volcano; KS1(≈1800 yr B.P.) and KS2(≈6000 yr B.P.) from the Ksudach calderas; KSht3(A.D. 1907) from Shtyubel cone in Ksudach volcanic massif; and KO (≈7700 yr B.P.) from the Kuril Lake-Iliinsky caldera. Tephra layers SH5(≈2600 yr B.P.) from Shiveluch volcano, AV3(≈4500 yr B.P.) from Avachinsky volcano, OPtr(≈4600 yr B.P.) from Opala volcano, KS3(≈6100 yr B.P.) and KS4(≈8800 yr B.P.) from Ksudach calderas, KSht1(≈1100 yr B.P.) from Shtyubel cone, and ZLT (≈4600 yr B.P.) from Iliinsky volcano cover smaller areas and have local stratigraphic value, as do the ash layers from the historically recorded eruptions of Shiveluch (SH1964) and Bezymianny (B1956) volcanoes. The dated tephra layers provide a record of the most voluminous explosive events in Kamchatka during the Holocene and form a tephrochronological timescale for dating and correlating various deposits.

Large-scale laboratory experiments on tsunamis generated by submarine volcanic eruptions in a wave basin

2020 ◽  
Author(s):  
Yibin Liu ◽  
Hermann M. Fritz
Keyword(s):  
Volcanic Eruption ◽  
Water Surface ◽  
Laboratory Experiments ◽  
Three Dimensional ◽  
Volcanic Eruptions ◽  
Explosive Eruptions ◽  
Wave Basin ◽  
Eruptive Column ◽  
Volcanic Tsunami ◽  
Underwater Camera

<p>Among the wide spectrum of volcanic tsunamis, the most devastating events have been caused by extremely explosive eruptions, pyroclastic flows and debris avalanches of underwater or near surface volcanos. The 2015 “orange” alert at the Kick ‘em Jenny submarine volcano in the Caribbean Sea highlighted the challenges in characterizing the tsunami waves for a potential submarine volcanic eruption. The 2018 Anak Krakatau eruption and flank collapse generated tsunami resulted in a near water surface setting of the volcanic vents similar to these laboratory experiments and relevant for the remaining and future tsunami hazards.</p><p>Source and runup scenarios are physically modeled using generalized Froude similarity in the three dimensional NHERI tsunami wave basin at Oregon State University. A novel volcanic tsunami generator (VTG) was deployed to study submarine volcanic eruptions with varying initial submergence and kinematics. The VTG consists of a telescopic eruptive column with an outer diameter of 1.2 m. The top cap of the pressurized eruptive column is accelerated vertically by eight synchronized 80 mm diameter pneumatic pistons with a stroke of 0.3 m. More than 300 experimental runs have been performed which include around 120 combinations of velocities and water depths. The variable eruption velocities of the VTG can mimic a wide range of processes ranging from relatively slow mud volcanoes and rapid explosive eruptions. The gravitational collapse of the eruptive column represents the potential engulfment and caldera formation. Water surface elevations and onshore runup are recorded by an array of resistance wave gauges and runup gauges. The VTG displacement is measured with an internal linear potentiometer and above and underwater camera recordings. Water surface reconstruction and kinematics are determined with a stereo particle image velocimetry (PIV) system. The water surface spike from the concentric collision of wave crest is observed under a limited range of Froude numbers. The energy conversion rates from the volcanic eruption to the wave train are quantified for various scenarios. Predictive equations of wave and spike characteristics are obtained and compared with existing linear and non-linear theories. The measured volcanic eruption and tsunami data serve to validate and advance three-dimensional numerical volcanic tsunami prediction models.</p>

scholarly journals Analysis of geoacoustic emission and electromagnetic radiation signals accompanying earthquake with magnitude Mw = 7.5

2020 ◽  
Vol 196 ◽  
pp. 03001
Author(s):  
Olga Lukovenkova ◽  
Alexandra Solodchuk
Keyword(s):  
Electromagnetic Radiation ◽  
Frequency Spectrum ◽  
Matching Pursuit ◽  
Kamchatka Peninsula ◽  
Pulse Waveform ◽  
Frequency Spectra ◽  
Pulse Detection ◽  
Geoacoustic Emission ◽  
Matching Pursuit Algorithm ◽  
Electromagnetic Signals

The paper is devoted to the analysis of frequency spectra and pulse waveform variety of the geoacoustic and electromagnetic signals recorded on Kamchatka Peninsula at “Karymshina” site during seismically calm and active periods. Signal pre-processing includes pulse detection and their waveforms reconstruction. A frequency spectrum is analyzed using the Adaptive Matching Pursuit algorithm. To study a variety of waveforms, each pulse is encoded by a special descriptive matrix. Then pulse classification based on similarity of the descriptive matrices is performed. Thus, a signal alphabet is formed. The authors analyzed the geophysical signals recorded before, during and after the earthquake with the magnitude Mw = 7.5 dated March 25, 2020. The obtained estimates of frequency spectra and signal alphabets are compared with the analysis results of signal recoded during the seismically calm period of March 22, 2020.

scholarly journals Analyses of LPG Dispersion During Its Accidental Release in Enclosed Car Parks

2017 ◽  
Vol 24 (2) ◽  
pp. 249-261
Author(s):  
Dorota Brzezińska ◽  
Marek Dziubiński ◽  
Adam S. Markowski
Keyword(s):  
High Explosive ◽  
Ventilation System ◽  
Visual Observation ◽  
Cloud Formation ◽  
Liquefied Petroleum Gas ◽  
Gas Dispersion ◽  
Accidental Release ◽  
Emission Time ◽  
Long Time ◽  
Gas Cloud

Abstract Despite the fact that LPG (Liquefied Petroleum Gas) is used in a large number of cars, tests have not yet been carried out to ascertain how hazardous can be the release of LPG from the car when parked in enclosed garages. The problem applies to both public and industrial parking areas, especially in Poland, where more than 10% cars are fueled by LPG. The paper describes full scale experiments, which demonstrate conditions that may occur in a garage in the event of accidental LPG release from the car installation. Over the course of the tests, a series of six LPG spillage tests were performed to study emission time and flammable cloud formation depending on the accidental gap diameter. Additionally, to enable the visual observation of the gas dispersion and influence of the ventilation system the experiment was conducted using well visible CO2 gas cloud, produced from dry ice. The experiments have shown that without ventilation LPG can accumulate on the floor of the enclosed garage for a long time, which generates a high explosive hazard. However, good ventilation (especially jet fan systems) can quickly remove hazardous flammable LPG clouds. Moreover, very important for effective LPG detection is the location of detectors closer to the floor than is currently recommended - at a height of 30 cm.

scholarly journals VLF – RECORDER FOR THE STUDY OF NATURAL RADIO EMISSION

2019 ◽  
pp. 105-116
Author(s):  
Г.И. Дружин ◽  
В.М. Пухов ◽  
Д.В. Санников ◽  
Е.И. Малкин ◽  
И.Е. Стасий
Keyword(s):  
Wave Propagation ◽  
Radio Emission ◽  
Electromagnetic Radiation ◽  
Radio Wave ◽  
Thunderstorm Activity ◽  
Radio Wave Propagation ◽  
Radio Waves ◽  
Natural Noise ◽  
Cosmophysical Research

С целью исследования естественных щумовых электромагнитных излучений в Институте космофизических исследований и распространения радиоволн ДВО РАН разработан и создан ОНЧрегистратор, установленный на Камчатке, в экспедиционном пункте Карымшина. Непрерывные наблюдения, проведенные с помощью ОНЧ регистратора, позволили исследовать различные геофизические эффекты, связанные с распространением радиоволн, грозовой активностью, землетрясениями, циклонами. In order to study the natural noise electromagnetic radiation at the Institute of Cosmophysical Research and Radio Wave Propagation FEB RAS, a VLFrecorder was developed, created and installed in Kamchatka, in the expedition point Karymshina. Continuous observations carried out with the help of VLFregistrator allowed to study various geophysical effects associated with the propagation of radio waves, thunderstorm activity, earthquakes, cyclones.

scholarly journals Towards a multitracer timeline of star formation in the LMC – I. Deriving the lifetimes of H i clouds

2020 ◽  
Vol 497 (2) ◽  
pp. 2286-2301 ◽  
Author(s):  
Jacob L Ward ◽  
Mélanie Chevance ◽  
J M Diederik Kruijssen ◽  
Alexander P S Hygate ◽  
Andreas Schruba ◽  
...  
Keyword(s):  
Star Formation ◽  
Time Scales ◽  
Time Scale ◽  
Molecular Clouds ◽  
Molecular Form ◽  
Cloud Formation ◽  
H Ii Regions ◽  
Star Forming ◽  
Atomic Gas ◽  
Gas Cloud

ABSTRACT The time-scales associated with the various stages of the star formation process remain poorly constrained. This includes the earliest phases of star formation, during which molecular clouds condense out of the atomic interstellar medium. We present the first in a series of papers with the ultimate goal of compiling the first multitracer timeline of star formation, through a comprehensive set of evolutionary phases from atomic gas clouds to unembedded young stellar populations. In this paper, we present an empirical determination of the lifetime of atomic clouds using the Uncertainty Principle for Star Formation formalism, based on the de-correlation of H α and H i emission as a function of spatial scale. We find an atomic gas cloud lifetime of 48$^{+13}_{-8}$ Myr. This time-scale is consistent with the predicted average atomic cloud lifetime in the LMC (based on galactic dynamics) that is dominated by the gravitational collapse of the mid-plane ISM. We also determine the overlap time-scale for which both H i and H α emissions are present to be very short (tover < 1.7 Myr), consistent with zero, indicating that there is a near-to-complete phase change of the gas to a molecular form in an intermediary stage between H i clouds and H ii regions. We utilize the time-scales derived in this work to place empirically determined limits on the time-scale of molecular cloud formation. By performing the same analysis with and without the 30 Doradus region included, we find that the most extreme star-forming environment in the LMC has little effect on the measured average atomic gas cloud lifetime. By measuring the lifetime of the atomic gas clouds, we place strong constraints on the physics that drives the formation of molecular clouds and establish a solid foundation for the development of a multitracer timeline of star formation in the LMC.

scholarly journals Supersonic gas streams enhance the formation of massive black holes in the early universe

Science ◽  
2017 ◽  
Vol 357 (6358) ◽  
pp. 1375-1378 ◽  
Author(s):  
Shingo Hirano ◽  
Takashi Hosokawa ◽  
Naoki Yoshida ◽  
Rolf Kuiper
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Early Universe ◽  
Big Bang ◽  
Cloud Formation ◽  
Massive Black Holes ◽  
Gas Condensation ◽  
Gas Streams ◽  
The Big Bang ◽  
Gas Cloud

The origin of super-massive black holes in the early universe remains poorly understood. Gravitational collapse of a massive primordial gas cloud is a promising initial process, but theoretical studies have difficulty growing the black hole fast enough. We report numerical simulations of early black hole formation starting from realistic cosmological conditions. Supersonic gas motions left over from the Big Bang prevent early gas cloud formation until rapid gas condensation is triggered in a protogalactic halo. A protostar is formed in the dense, turbulent gas cloud, and it grows by sporadic mass accretion until it acquires 34,000 solar masses. The massive star ends its life with a catastrophic collapse to leave a black hole—a promising seed for the formation of a monstrous black hole.

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