Volcanically extruded phosphides as an abiotic source of Venusian phosphine

We hypothesize that trace amounts of phosphides formed in the mantle are a plausible abiotic source of the Venusian phosphine observed by Greaves et al. [Nat. Astron., https://doi.org/10.1038/s41550-020-1174-4 (2020)]. In this hypothesis, small amounts of phosphides (P3− bound in metals such as iron), sourced from a deep mantle, are brought to the surface by volcanism. They are then ejected into the atmosphere in the form of volcanic dust by explosive volcanic eruptions, which were invoked by others to explain the episodic changes of sulfur dioxide seen in the atmosphere [Esposito, Science 223, 1072–1074 (1984)]. There they react with sulfuric acid in the aerosol layer to form phosphine (2 P3− + 3H2SO4 = 2PH3 + 3SO42-). We take issue with the conclusion of Bains et al. [arXiv:2009.06499 (2020)] that the volcanic rates for such a mechanism would have to be implausibly high. We consider a mantle with the redox state similar to the Earth, magma originating deep in the mantle—a likely scenario for the origin of plume volcanism on Venus—and episodically high but plausible rates of volcanism on a Venus bereft of plate tectonics. We conclude that volcanism could supply an adequate amount of phosphide to produce phosphine. Our conclusion is supported by remote sensing observations of the Venusian atmosphere and surface that have been interpreted as indicative of currently active volcanism.

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The Tectonic Plates are Moving!

10.1093/oso/9780198717867.001.0001 ◽

2018 ◽

Cited By ~ 1

Author(s):

Roy Livermore

Keyword(s):

Plate Tectonics ◽

First Generation ◽

Volcanic Eruptions ◽

Short Article ◽

Tectonic Plates ◽

The Earth ◽

Deep Interior ◽

Two Generations ◽

The 1960S

Written in a witty and informal style, this book explains modern plate tectonics in a non-technical manner, showing not only how it accounts for phenomena such as great earthquakes, tsunamis, and volcanic eruptions, but also how it controls conditions at the Earth’s surface, including global geography and climate, making it suitable for life. The book presents the advances that have been made since the establishment of plate tectonics in the 1960s, highlighting, on the fiftieth anniversary of the theory, the contributions of a small number of scientists who have never been widely recognized for their discoveries. Beginning with the publication of a short article in Nature by Vine and Matthews, the book traces the development of plate tectonics through two generations of the theory. First-generation plate tectonics covers the exciting scientific revolution of the 1960s, its heroes, and its villains. The second generation includes the rapid expansions in sonar, satellite, and seismic technologies during the 1980s and 1990s that provided a truly global view of the plates and their motions, and an appreciation of the role of their within the Earth system. Arriving at the cutting edge of the science, the latest results from studies using techniques such as seismic tomography and mineral physics to probe the deep interior are discussed and the prospects for finding plate tectonics on other planets assessed. Ultimately, the book leads to the startling conclusion that, without plate tectonics, the Earth would be as lifeless as Venus.

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Smaller average stratospheric aerosol sizes after volcanic eruptions in 2018 and 2019

10.5194/egusphere-egu21-4309 ◽

2021 ◽

Author(s):

Felix Wrana ◽

Christian von Savigny ◽

Larry W. Thomason

Keyword(s):

Remote Sensing ◽

Volcanic Eruptions ◽

Stratospheric Aerosol ◽

Aerosol Layer ◽

Spatial Evolution ◽

Size Distributions ◽

Number Density ◽

Temporal And Spatial Evolution ◽

Solar Occultation ◽

Temporal And Spatial

We present surprising results of our stratospheric aerosol size retrieval which is using the SAGE III/ISS solar occultation measurements, that started in 2017. Due to the broad wavelength spectrum covered by the instrument a robust retrieval of the median radius, mode width and number density of monomodal lognormal size distributions is possible.In the timeframe of SAGE III&#8217;s operation so far three small to mid intensity volcanic eruptions that reached and perturbed the stratospheric aerosol layer were observed by the instrument: The Ambae eruptions (15.3&#176;S) in spring of 2018 and the Raikoke (48.3&#176;N) and Ulawun (5.05&#176;S) eruptions, both in June 2019. While the Raikoke eruption led to an increase in the median radius of the stratospheric aerosols, which was to be expected and is in line with previous observations, the Ambae and Ulawun eruption had a different effect. After both eruptions the average aerosol size decreased, with lower median radii and narrower size distributions, while the number density increased strongly. The observation, that volcanic eruptions may lead to smaller average stratospheric aerosol sizes is a novel one and should be of great interest to the modeling as well as remote sensing community.We will present the temporal and spatial evolution of the stratospheric perturbations and discuss what may distinguish those three eruptions from each other.

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The effects and consequences of very large explosive volcanic eruptions

Philosophical Transactions of The Royal Society A Mathematical Physical and Engineering Sciences ◽

10.1098/rsta.2006.1814 ◽

2006 ◽

Vol 364 (1845) ◽

pp. 2073-2097 ◽

Cited By ~ 197

Author(s):

S Self

Keyword(s):

Financial Markets ◽

Explosive Eruption ◽

Volcanic Eruptions ◽

Light Levels ◽

The Earth ◽

Major Disruption ◽

Explosive Volcanic Eruptions ◽

Modern Experience ◽

The Cost ◽

Large Meteorite

Every now and again Earth experiences tremendous explosive volcanic eruptions, considerably bigger than the largest witnessed in historic times. Those yielding more than 450 km 3 of magma have been called super-eruptions. The record of such eruptions is incomplete; the most recent known example occurred 26 000 years ago. It is more likely that the Earth will next experience a super-eruption than an impact from a large meteorite greater than 1 km in diameter. Depending on where the volcano is located, the effects will be felt globally or at least by a whole hemisphere. Large areas will be devastated by pyroclastic flow deposits, and the more widely dispersed ash falls will be laid down over continent-sized areas. The most widespread effects will be derived from volcanic gases, sulphur gases being particularly important. This gas is converted into sulphuric acid aerosols in the stratosphere and layers of aerosol can cover the global atmosphere within a few weeks to months. These remain for several years and affect atmospheric circulation causing surface temperature to fall in many regions. Effects include temporary reductions in light levels and severe and unseasonable weather (including cool summers and colder-than-normal winters). Some aspects of the understanding and prediction of super-eruptions are problematic because they are well outside modern experience. Our global society is now very different to that affected by past, modest-sized volcanic activity and is highly vulnerable to catastrophic damage of infrastructure by natural disasters. Major disruption of services that society depends upon can be expected for periods of months to, perhaps, years after the next very large explosive eruption and the cost to global financial markets will be high and sustained.

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Origins and Spatial Distribution of Non-Pure Sulfate Particles (NSPs) in the Stratosphere Detected by the Balloon-Borne Light Optical Aerosols Counter (LOAC)

Atmosphere ◽

10.3390/atmos11101031 ◽

2020 ◽

Vol 11 (10) ◽

pp. 1031

Author(s):

Jean-Baptiste Renard ◽

Gwenaël Berthet ◽

Anny-Chantal Levasseur-Regourd ◽

Sergey Beresnev ◽

Alain Miffre ◽

...

Keyword(s):

Spatial Distribution ◽

Sulfuric Acid ◽

Dust Cloud ◽

Volcanic Eruptions ◽

Interplanetary Dust ◽

Meteor Shower ◽

The Earth ◽

Large Particles ◽

Main Component ◽

Aerosol Counter

While water and sulfuric acid droplets are the main component of stratospheric aerosols, measurements performed for about 30 years have shown that non-sulfate particles (NSPs) are also present. Such particles, released from the Earth mainly through volcanic eruptions, pollution or biomass burning, or coming from space, present a wide variety of compositions, sizes, and shapes. To better understand the origin of NSPs, we have performed measurements with the Light Optical Aerosol Counter (LOAC) during 151 flights under weather balloons in the 2013–2019 period reaching altitudes up to 35 km. Coupled with previous counting measurements conducted over the 2004–2011 period, the LOAC measurements indicate the presence of stratospheric layers of enhanced concentrations associated with NSPs, with a bimodal vertical repartition ranging between 17 and 30 km altitude. Such enhancements are not correlated with permanent meteor shower events. They may be linked to dynamical and photophoretic effects lifting and sustaining particles coming from the Earth. Besides, large particles, up to several tens of μm, were detected and present decreasing concentrations with increasing altitudes. All these particles can originate from Earth but also from meteoroid disintegrations and from the interplanetary dust cloud and comets.

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PILGRIMAGES AND PERSISTENT SOCIAL MEMORY IN SPITE OF VOLCANIC DISASTERS IN THE ARENAL AREA, COSTA RICA

Ancient Mesoamerica ◽

10.1017/s0956536111000265 ◽

2011 ◽

Vol 22 (2) ◽

pp. 425-435 ◽

Cited By ~ 7

Author(s):

Payson Sheets

Keyword(s):

Remote Sensing ◽

Residential Mobility ◽

Social Memory ◽

Volcanic Eruptions ◽

Explosive Eruptions ◽

The People ◽

South Shore ◽

Explosive Volcanic Eruptions ◽

The Village ◽

Ecological Recovery

AbstractAncient Costa Ricans in the Arenal area exhibited extraordinary persistence in landscape use and social memory, in spite of repeated catastrophes caused by explosive volcanic eruptions. The Cañales village on the south shore of Lake Arenal was struck by two large explosive eruptions during the Arenal phase (500 b.c.–a.d. 600). Following ecological recovery, the village was reoccupied after each of these eruptions. I argue that the people who reoccupied the village were direct descendants of pre-disaster villagers due to the fact that they reinstated use of the same path to the village cemetery. While previous interpretations emphasized ecological reasons for village reoccupation, I suggest that a dominating reason for reoccupation was to re-establish contact with the spirits of deceased ancestors in the cemetery. The living and the spirits of the deceased constituted the functioning community. The refugees re-established processional access to their cemetery as soon as possible, perhaps even before the village was reoccupied. Archaeologists rarely discover evidence of ancient pilgrimages. However, the combination of remote sensing and detailed stratigraphic analyses allow them to be detected in the Arenal area. Villagers created and perpetuated social memory by regular linear ritual processions along precisely the same path, in spite of challenging topography and occasional regional disasters obscuring the path. This recognition has implications for the arguments of sedentism versus residential mobility during the Arenal phase.

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Development of the muographic tephra deposit monitoring system

Scientific Reports ◽

10.1038/s41598-020-71902-1 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Hiroyuki K. M. Tanaka

Keyword(s):

Remote Sensing ◽

Monitoring System ◽

River Basin ◽

Volcanic Eruptions ◽

Average Density ◽

Airborne Remote Sensing ◽

Sakurajima Volcano ◽

Tephra Deposit ◽

Explosive Volcanic Eruptions ◽

Tephra Fallout

Abstract Measurements of volcanic tephra fallout deposits provide useful information about the magnitude and intensity of explosive volcanic eruptions and potential for remobilization of deposits as dangerous volcanic flows. However, gathering information in the vicinity of erupting craters is extremely dangerous, and moreover, it is often quite difficult to determine deposit thickness proximal to volcanic craters because the thickness of the deposit is too great to easily measure; thus, airborne remote sensing technologies have generally been utilized during the intermission between eruptions. As an alternative tool, a muographic tephra deposit monitoring system was developed in this work. Here we report the performance of this system by applying the muographic data acquired at Sakurajima volcano, Japan as an example. By assuming the average density of the deposit was 2.0 g cm−3, the deposit thicknesses measured with muography were in agreement with the airborne results, indicating that volcanic fallout built up within the upper river basin, showed its potential for monitoring the episodic tephra fallouts even during eruptions.

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Global rates of continental volcanism on Earth

10.5194/egusphere-egu2020-19414 ◽

2020 ◽

Author(s):

Paolo Papale ◽

Warner Marzocchi ◽

Deepak Garg

Keyword(s):

Volcanic Eruption ◽

Plate Tectonics ◽

Large Scale ◽

Time Windows ◽

Volcanic Eruptions ◽

Volcanic Hazards ◽

Basic Knowledge ◽

The Earth ◽

Global Volcanism ◽

Event Times

Knowledge of the rates of Earth volcanism and their variability is critical in many fields involving global assessments, such as plate tectonics and associated rates of crustal formation and consumption, large-scale volcanic hazards, climate change, etc. Global rates also provide the base rate to which regional or individual volcano data can be compared, in order to quantify differences and similarities providing guidance in the identification of volcanoes with overall analogue behaviors. While global volcanic eruption databases, such as the Smithsonian Global Volcanism Project database or the Large Magnitude Explosive Volcanic Eruptions database at BGS, provide the required basic knowledge, substantial deterioration of the geologic information with age has been a serious obstacle to a comprehensive picture. Recent understanding that global eruption inter-event times are exponentially distributed, that being the essential character of Poisson distributed events, is leading to a general model for the global eruption behavior of the Earth. Exponential distributions are entirely characterized by one single rate parameter. Comparing the rate parameters for different VEI classes of eruptions, as well as analyzing the distribution of individual eruption volumes within and across different VEI classes, reveals that relative frequencies for the explosive eruptions with VEI higher than 2 distribute as a power law. This knowledge is employed a) to quantify the global volcanic hazard, in particular in relation to the occurrence of globally impacting eruptions, comparing with known hazards from many well-known adverse events; and b) within a Monte Carlo simulation of the eruptive history of the Earth, allowing us to quantify the distribution of volcanic eruption rates, both in number and volume, and globally or for each given VEI class or group of VEI classes, over different observational time windows from 1 to 100,000 years.

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