Is a whole-mantle convection the key to solving the Tunguska 1908 problem?

2020 ◽  
Author(s):  
Boris R. German
Keyword(s):  
Solar Flare ◽  
Mantle Convection ◽  
Shear Velocity ◽  
Outer Core ◽  
Surface Uplift ◽  
The Earth ◽  
Eastern Australia ◽  
Solar Perturbations ◽  
Tunguska Event ◽  
The Impact

<p>It is generally accepted that the Tunguska event in Siberia on 30 June, 1908 resulted from an explosion of cosmic body. However, there is no common agreement that this bolide really existed. Moreover, registered ultra low frequency (ULF) magnetic oscillations in Kiel, Germany on 27-30 June 1908 [1] had a correlate with the 'acoustic halo' (ULF) of a solar flare [2].</p><p>Large low-shear velocity provinces (LLSVPs) are linked to so-called blobs located atop the Earth's outer core [3]. It was shown the Earth's D"-layer core-mantle boundary was perturbed by both the solar flare and an anomalous lunar-solar tide during the Tunguska 1908 event [2]. Therefore, gravitational/magnetic lunar-solar perturbations could have triggered a plume/hotspot/LIP activation by means of a LLSVPs convection.</p><p>It was suggested that planetary hotspots chains are interconnected [4]. Indeed, during the Tunguska event brightest glows were observed over the Eifel volcano and more weak one over the Yellowstone volcano (both volcanoes are associated with hotspots) [5]. In addition, day by day a slowly lifting of the earth round the diabase stones was registered in Tasmania from 7 June till 29 June, 1908 [6]. This lifting was independent from atmospheric temperature variations and terminated as soon as a blast took place in the caldera of Tunguska paleovolcano on 30 June, 1908 [5, 6]. Observations in Tasmania remained a mystery for a long time. Recently scientists discovery the Cosgrove hotspot had moved from Eastern Australia to Tasmania [7]. In our opinion, the Cosgrove did not lose its activity fully 9 My ago as previously assumed: the Darwin crater in Tasmania originated about of 803 ka years and large volume ejected glasses in/around this small crater contradicts to the impact origin [5, 8]. Therefore, we consider the underground activation of Cosgrove hotspot as a cause of surface uplift in Tasmania from 7 to 30 June 1908.</p><p>As in Tasmania, moving mantle hotspots were registered in Eastern Siberia [9]. Probably, hotspots in Tasmania (near Pacific LLSVPs) and in the Tunguska basin (near Perm LLSVPs) are interconnected. Because common hotspots thermal energy was released in/by the Tunguska paleovolcano explosion on 30 June 1908, the fluidal pressure of the Cosgrove hotspot under Tasmania was reduced, resulting in the termination of surface uplift. Since meteorites could not have caused the earth uplift in Tasmania, the impact hypothesis for the Tunguska phenomenon can be excluded. All data favor an endogenic origin of this event due to lunar-solar perturbations and the whole-mantle convection.</p><p><span>[1]. Weber L. (1908) Astronomische Nachrichten, </span><strong><span>178</span></strong><span>, 23. [2]. German B. (2010) EPSC2010-430. [3]. Duncombe J. (2019) Eos, </span><strong><span>100</span></strong><span>. [4]. Courtillot V. (1990) ISBN 9780813722474, 401. [5]. German B. (2019) ISBNs 9783981952605(in Russian)/9783981952612(in English). [6]. Scott H. (1908) Nature, </span><strong><span>78</span></strong><span>(2025), 376. [7]. Davies D. (2015) Nature, </span><strong><span>525</span></strong><span>, 511. [8]. Haines P. (2005) Australian Journal Earth Sciences, </span><strong><span>52</span></strong><span>, 481. [9]. Rosen O. (2015) ISBN 9785902754954, 148.</span></p>

scholarly journals THEORIES OF CONTINENTAL DRIFT

2020 ◽  
Vol 17 (3) ◽  
pp. 1513-1518
Author(s):  
Vishvantha D Veeraiyan ◽  
Dr. Deepak Nallasamy V
Keyword(s):  
Mantle Convection ◽  
Continental Drift ◽  
The Earth ◽  
Plate Formation ◽  
The Impact ◽  
The Way

Continental drift is the process of continental plates moving. The movement is very slow, and it might take even years to show the impact on the Earth. The movement depends on gravity, convection drift, and plate formation. Gravity impacts the movements as the mantle (The layer below the crust) is always spinning because of gravity and the plates are located on the mantle. Convection drift impacts on the movement because convection drift is a cycle of melting and cooling of rocks in the mantle which can slowly impact the movement of the plate. Plate formation also affects the way the plates move as the new plates formed pushes the nearby plates causing movement.

Formation of Lunar Craters and Bright Rays as a Result of Meteorite Impacts

1962 ◽  
Vol 14 ◽  
pp. 415-418
Author(s):  
K. P. Stanyukovich ◽  
V. A. Bronshten
Keyword(s):  
Explosive Charge ◽  
The Moon ◽  
Meteorite Impacts ◽  
The Earth ◽  
Lunar Craters ◽  
The Impact

The phenomena accompanying the impact of large meteorites on the surface of the Moon or of the Earth can be examined on the basis of the theory of explosive phenomena if we assume that, instead of an exploding meteorite moving inside the rock, we have an explosive charge (equivalent in energy), situated at a certain distance under the surface.

PLANETARY SELF-ORGANIZATION

2020 ◽  
Vol 42 (3) ◽  
pp. 271-282
Author(s):  
OLEG IVANOV
Keyword(s):  
Dynamical System ◽  
Heat Source ◽  
Mantle Convection ◽  
Plate Tectonics ◽  
Rotation Speed ◽  
Self Organization ◽  
Heat Sources ◽  
Kinematic Parameters ◽  
The Earth ◽  
New Type

The general characteristics of planetary systems are described. Well-known heat sources of evolution are considered. A new type of heat source, variations of kinematic parameters in a dynamical system, is proposed. The inconsistency of the perovskite-post-perovskite heat model is proved. Calculations of inertia moments relative to the D boundary on the Earth are given. The 9 times difference allows us to claim that the sliding of the upper layers at the Earth's rotation speed variations emit heat by viscous friction.This heat is the basis of mantle convection and lithospheric plate tectonics.

Ups and Downs

2018 ◽  
Author(s):  
Roy Livermore
Keyword(s):  
Mantle Convection ◽  
Laboratory Experiments ◽  
Inner Core ◽  
Computer Modelling ◽  
Great Depth ◽  
New Horizons ◽  
The Core ◽  
The Earth ◽  
The World ◽  
The 1960S

Despite the dumbing-down of education in recent years, it would be unusual to find a ten-year-old who could not name the major continents on a map of the world. Yet how many adults have the faintest idea of the structures that exist within the Earth? Understandably, knowledge is limited by the fact that the Earth’s interior is less accessible than the surface of Pluto, mapped in 2016 by the NASA New Horizons spacecraft. Indeed, Pluto, 7.5 billion kilometres from Earth, was discovered six years earlier than the similar-sized inner core of our planet. Fortunately, modern seismic techniques enable us to image the mantle right down to the core, while laboratory experiments simulating the pressures and temperatures at great depth, combined with computer modelling of mantle convection, help identify its mineral and chemical composition. The results are providing the most rapid advances in our understanding of how this planet works since the great revolution of the 1960s.

scholarly journals The potentially hazardous NEA 2001 BB16

2019 ◽  
Vol 28 (1) ◽  
pp. 180-190
Author(s):  
Ireneusz Wlodarczyk
Keyword(s):  
Mean Value ◽  
Optical Observations ◽  
Uniform Sampling ◽  
The Earth ◽  
22Nd Century ◽  
Lyapunov Time ◽  
Gravitational Model ◽  
Calculated Probability ◽  
Potential Impact ◽  
The Impact

AbstractWe computed the impact solutions of the potentially dangerous Near Earth Asteroid (NEA) 2001 BB16 based on 47 optical observations from January 20.08316 UTC, 2001, through February 09.15740 UTC, 2016, and one radar observation from January 19.90347 UTC, 2016. We used two methods to sample the starting Line of Variation (LOV). First method, called thereafter LOV1, with the uniform sampling of the LOV parameter, out to LOV = 5 computing 3000 virtual asteroids (VAs) on both sides of the LOV, which gives 6001 VAs and propagated their orbits to JD2525000.5 TDT=February 12, 2201. We computed the non-gravitational parameterA2=(34.55±7.38)·10–14 au/d2 for nominal orbit of 2001 BB16 and possible impacts with the Earth until 2201. For potential impact in 2195 we find A2=20.0·10−14 au/d2. With a positive value of A2, 2001 BB16 can be prograde rotator. Moreover, we computed Lyapunov Time (LT) for 2001 BB16, which for all VAs, has a mean value of about 25 y. We showed that impact solutions, including the calculated probability of a possible collision of a 2001 BB16 asteroid with the Earth depends on how to calculate and take into account the appropriate gravitational model, including the number of perturbing massive asteroids. In some complicated cases, it may depend also on the number of clones calculated for a given sigma LOV1. The second method of computing the impact solutions, called thereafter LOV2, is based on a non-uniformly sampling of the LOV. We showed that different methods of sampling the LOV can give different impact solutions, but all computed dates of possible impacts of the asteroid 2001 BB16 with the Earth occur in accordance at the end of the 22nd century.

Tidal excitation of hydromagnetic waves and their damping in the Earth

1994 ◽  
Vol 274 ◽  
pp. 219-241 ◽  
Author(s):  
R. R. Kerswell
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
Outer Core ◽  
Decay Rates ◽  
Wave Disturbance ◽  
Instability Mechanism ◽  
The Earth ◽  
Elliptical Instability ◽  
Hydromagnetic Waves

We examine the possibility that the Earth's outer core, as a tidally distorted fluid-filled rotating spheroid, may be the seat of an elliptical instability. The instability mechanism is described within the framework of a simple Earth-like model. The preferred forms of wave disturbance are explored and a likely growth rate supremum deduced. Estimates are made of the Ohmic and viscous decay rates of such hydromagnetic waves in the outer core. Rather than a conclusive disparity of scales, we find that typical elliptical growth rates, Ohmic decay rates and viscous decay rates all have the same order for plausible core fields and core-to-mantle conductivities. This study is all the more timely considering the recent realization that the Earth's precession may also drive similar instabilities at comparable strengths in the outer core.

On the reliability of PKIIKP phase identification at a single station

2021 ◽  
Author(s):  
Olga Usoltseva ◽  
Vladimir Ovtchinnikov
Keyword(s):  
Inner Core ◽  
Seismic Velocity ◽  
Seismic Station ◽  
Shear Velocity ◽  
Outer Core ◽  
Joint Analysis ◽  
Time Range ◽  
Model Parameters ◽  
Phase Identification ◽  
Single Station

<p><span>Study of the contact zone between the inner and outer core represents considerable interest for understanding of properties, structures and dynamic of the Earth's core. One of </span><span>the </span><span>sources of </span><span>the </span><span>data about the processes proceeding in the top part of the inner core is the seismic wave PKIIKP once reflected from an undersize inner core boundary. Amplitudes of these waves are sensitive to the shear velocity in the top part of the inner core and are small. Therefore their identification at a single seismic station is not reliable without application of additional methods of analysis. </span><span>Significant in this regard is the discussion about the source (in inner core or in mantle) of anomalous arrivals<!-- Это можно удалить --> detected at the TAM station in North Africa [1,2] in the time range of PKIIKP phase.</span></p><p><span>To estimate influence of model parameters (S and P seismic velocity) on the characteristics of PKIIKP wave (amplitude and travel time) we calculated sensitivity kernels for upper mantle and inner core for dominant period 1.2 s, azimuth step 0.2 degrees and radius step 20 km by using DSM Kernel Suite algorithm. It was revealed that PKIIKP amplitude is more sensitivities to mantle heterogeneities than to inner core ones. </span><span>For reducing the effects of the overlying structures we suppose to use </span>а <span>joint analysis PKIIKP and pPKIIKP waves. </span><span>With this approach, an incorrect i</span><span>dentification</span><span> of the PKIIKP wave is most likely excluded. </span><span>We<!-- Было бы хорошо привести пример --> demonstrate the effectiveness of the approach on the example of processing the seismogram of the 11.02.2015 earthquake re</span>с<span>o</span><span>rded at the GZH station in China at a distance of 179.4 degrees.</span></p><p><span>1. Wang W., Song X. Analyses of anomalous amplitudes of antipodal PKIIKP waves</span><span>,</span><span> E<!-- Удаляется вместе с текстом, выделенным выше Зеленым цветом. -->aPP. 2019. V. 3. P. 212-217. doi: 10.26464/epp2019023</span></p><p><span>2. Tsuboi S., Butler R. Inner core differential rotation inferred from antipodal seismic observations</span><span>,</span><span> PEPI</span><span>,</span><span> 2020. V.301. 106451. </span></p>

Hospitalitas Kristen Yang Hampir Hilang Pada Kasus Kematian Salah Satu Anggota Masyarakat Di Dusun Beringin, Luwu Utara, Sulawesi Selatan Akibat Covid-19

2021 ◽  
Author(s):  
desna rura sarapang
Keyword(s):  
Virus Disease ◽  
Social Distancing ◽  
Indonesian Government ◽  
Risk Of Death ◽  
The Earth ◽  
Corona Virus ◽  
The World ◽  
Global World ◽  
The Impact ◽  
Christian Hospitality

The emergence of a new virus in the global world at the end of 2019, namely Corona Virus Disease 2019, brought tremendous excitement to all inhabitants of the earth. The emergence of this virus brings tremendous concern and fear to the world because the spread of this virus is quite fast, even the most frightening is that the risk of death of people exposed to this virus is very large. Indonesia itself, cannot avoid the impact of this Covid-19 case. As a form of efforts to prevent and minimize transmission of the virus, the Indonesian government has issued a social distancing / physical distancing recommendation. This situation also causes the interaction between communities to be very limited. This situation seems to be able to eliminate hospitality among the community. This paper aims to emphasize the importance of maintaining the value of Christian hospitality in society amid the Covid-19 pandemic.

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