Magma ascent and eruption forecasting at Deception Island volcano (Antarctica) evidenced by δD and δ18O variations

2020 ◽  
Author(s):  
Antonio M. Álvarez-Valero ◽  
Meritxell Aulinas ◽  
Adelina Geyer ◽  
Guillem Gisbert ◽  
Gabor Kereszturi ◽  
...  
Keyword(s):  
Melt Inclusions ◽  
Volcanic Eruptions ◽  
Volcanic Hazards ◽  
Magma Ascent ◽  
Explosive Eruptions ◽  
Deception Island ◽  
Essential Information ◽  
Local Modification ◽  
Isotopic Variations ◽  
Active Volcanoes

<p>Geochemistry of volatiles in active volcanoes provides insights into the magmatic processes and evolution at depth, such as magma evolution and degassing, which can be implemented into volcanic hazards assessment. Deception Island is one of the most active volcanoes in Antarctica, with more than twenty explosive eruptions documented over the past two centuries. Hydrogen and oxygen isotopic variations in the volatiles trapped in the Deception Island rocks (glass and melt inclusions in phenocrysts) provide essential information on the mechanisms controlling the eruptive history in this volcanic suite. Thus, understanding the petrological and related isotopic variations in the island, has the potential to foresee the possible occurrence and its main eruptive features of a future eruption.</p><p>Information from hydrogen and oxygen stable isotopes combined with detailed petrologic data reveal in Deception Island (i) fast ascent and quenching of most magmas, preserving pre-eruptive magmatic signal of water contents and isotopic ratios, with local modification by rehydration due to glass exposition to seawater, meteoric and fumarolic waters; (ii) a plumbing system(s) currently dominated by closed-system degassing leading to explosive eruptions; (iii) control on the interactions of ascending magmas with the surface waters producing hydrovolcanic activity throughout the two main fault systems in Deception Island. These results can be considered in further studies of volcanic monitoring to improve the capability to interpret geophysical data and signals recorded during volcanic unrest episodes, and hence, forecast volcanic eruptions and related hazards.</p><p>This research was partially funded by the following projects: POSVOLDEC (CTM2016‐79617‐P) (AEI/FEDER‐UE), VOLGASDEC (PGC2018-095693-B-I00) (AEI/FEDER‐UE) and Programa Propio Ib-2019 (USAL). This research is also part of POLARCSIC activities.</p>

A myriad of melt inclusions: a synchrotron microtomography study of melt inclusions and vapour bubbles from Colli Albani (Italy)

2021 ◽  
Author(s):  
Corin Jorgenson ◽  
Luca Caricchi ◽  
Michael Stueckelberger ◽  
Giovanni Fevola ◽  
Gregor Weber
Keyword(s):  
Melt Inclusions ◽  
Melt Inclusion ◽  
Fluid Phase ◽  
Volcanic Eruptions ◽  
Mineral Chemistry ◽  
Magma Ascent ◽  
Vapour Bubble ◽  
Electron Synchrotron ◽  
Colli Albani ◽  
Synchrotron Microtomography

<p>Melt inclusions provide a window into the inner workings of magmatic systems. Both mineral chemistry and volatile distributions within melt inclusions can provide valuable information about the processes modulating magma ascent and preceding volcanic eruptions. Many melt inclusions host vapour bubbles which can be rich in CO<sub>2</sub> and H<sub>2</sub>O and must be taken into consideration when assessing the volatile budget of magmatic reservoirs. These vapour bubbles can be the product of differential volumetric contraction between the melt inclusion and host phase during an eruption or indicate an excess fluid phase in the magma reservoir. Thus, determining the distribution of volatiles between melt and vapour bubbles is integral to our fundamental understanding of melt inclusions, and by extension the evolution of volatiles within magmatic systems.</p><p>A large dataset of 79 high-resolution tomographic scans of clinopyroxene and leucite phenocrysts from the Colli Albani Caldera Complex (Italy) was recently acquired at the German Electron Synchrotron (DESY). These tomograms allow us to quantify the volume of melt inclusions and associated vapour bubble both glassy and microcrystalline melt inclusions. Notably, in the glassy melt inclusions the vapour bubbles exist either as a single large vapour bubble in the middle of the melt inclusion or as several smaller vapour bubbles distributed around the edge of the melt inclusion. These two types of melt inclusions can coexist within a single crystal. We suggest that the occurrence of these rim- bubbles is caused by one of two exsolution pathways, either pre-entrapment and bubble migration or post entrapment with preferential exsolution at the rims. By combining the analysis of hundreds of melt inclusions with the chemistry of the host phase we aim to unveil magma ascent rates and distribution of excess fluids within the magmatic system of Colli Albani, which produced several mafic-alkaline large volume ignimbrites.</p>

scholarly journals ANALYSIS OF CHANGES IN THE STATE OF ECOSYSTEMS ON ATLASOVA ISLAND (KURIL ISLANDS)

2020 ◽  
Vol 25 (3) ◽  
pp. 139-150
Author(s):  
Alexey A. Verkhoturov ◽  
Keyword(s):  
Vegetation Index ◽  
Rapid Assessment ◽  
Volcanic Eruptions ◽  
Volcanic Hazards ◽  
The State ◽  
Kuril Islands ◽  
Explosive Eruptions ◽  
Large Area ◽  
A Chain ◽  
Surrounding Areas

The territory of the Kuril Islands is a chain of volcanic structures and is subject, to certain extent, to volcanic hazards. Atlasova Island is composed of products of the Alaid volcano, which is characterized by effusive and explosive activity. The article analyzes the changes in ecosystems on Atlasov island, which are periodically caused by the Alaid volcano eruption. Large amount of pyroclastic material are brought to the surface during explosive eruptions: blocks, bombs, tephra, lapilli and volcanic ash, which is transported in the atmosphere over very long distances. Ecosystems are affected by pyroclastic deposition over a large area of island land. The purpose of this study was to identify the nature and extent of changes in the state of ecosystems affected by volcanic eruptions from multi-zone satellite images of medium resolution. Analysis of data obtained from space systems Landsat and Sentinel for the period 1972 to 2020, in GIS environment allowed us to trace the dynamics and character of the successions to the affected areas on the calculated values of the vegetation index NDVI. Techniques developed in the process of studying this issue can further facili-tate rapid assessment of impacts on ecosystems at the effusive-explosive eruptions and forecast volcanic hazard for surrounding areas.

A combined 2-D/1-D magma ascent model of explosive volcanic eruptions

2019 ◽  
Vol 219 (3) ◽  
pp. 1818-1835
Author(s):  
Hélène Massol
Keyword(s):  
Volume Fraction ◽  
Experimental Studies ◽  
Volcanic Eruptions ◽  
Gas Content ◽  
Magma Ascent ◽  
Explosive Eruptions ◽  
Shear Stresses ◽  
Order Of Magnitude ◽  
Gas Volume Fraction ◽  
Gas Volume

SUMMARY Explosive eruptions involve the fragmentation of magma that changes the flow regime from laminar to turbulent within the volcanic conduit during ascent. If the gas volume fraction is high, magma fragments and the eruption style is explosive, but if not, the magma flows effusively out of the vent. Gas escape processes depend on how the magma can rupture, and recent experimental studies measured rupture stress thresholds of the order of a few megapascals. It is thus critical to model the gas content and state of stress evolution in the flowing magma within the conduit. We present a new self-consistent model of an explosive eruption from the magma chamber to the surface, based on a critical gas volume fraction. Our model allows to explore irregular geometries below the fragmentation level (2-D). We first compare our model with classical 1-D models of explosive eruptions and find that in the case of straight conduits and fragmented flows, 1-D models are accurate enough to model the gas pressure and vertical velocity distribution in the conduit. However, in the case of an irregular conduit shape at depth, 2-D models are necessary. Despite a certain conduit radius visible at the surface, very different stress fields within the flow could be present depending upon the position and shape of any conduit irregularities. Stresses of the order of more than 1 MPa can be attained in some locations. High tensile stresses are located at the centre of the conduit, while high shear stresses are located at the conduit walls leading to several potential rupture locations. Due to the interplay between the velocity field and decompression rate, similar conduit radius visible at the surface might also lead to very different fragmentation depths with a difference of more than 1500 m between an enlarged conduit shape at some depth and a straight conduit. At depth, different conduit sizes might lead to the same order of magnitude for the mass flux, depending on the conduit geometry.

The effect of nanolites on degassing of silica-rich magma

2020 ◽  
Author(s):  
Francisco Cáceres ◽  
Fabian Wadsworth ◽  
Bettina Scheu ◽  
Mathieu Colombier ◽  
Claudio Madonna ◽  
...  
Keyword(s):  
Ambient Pressure ◽  
Volcanic Eruptions ◽  
Bubble Nucleation ◽  
Magma Ascent ◽  
Explosive Eruptions ◽  
Initial Water Content ◽  
Primary Control ◽  
Number Density ◽  
Bubble Number ◽  
Bubble Number Density

<p>Magma degassing dynamics play an important role controlling the explosivity of volcanic eruptions. Some of the largest explosive eruptions in history have been fed by silica-rich magmas in volcanic systems with complex dynamics of volatiles degassing. Degassing of magmatic water drives bubble nucleation and growth, which in turn increases magma buoyancy and results in magma ascent and an eventual eruption. While micro- to milli-meter sized crystals are known to cause heterogeneous bubble nucleation and to facilitate bubble coalescence, the effects of nanolites remains mostly unexplored. Nanolites have been hypothesized to be a primary control on the eruptive style of silicic volcanoes, however the mechanisms behind this control remains unclear.</p><p>Here we use an experimental approach to show how nanolites dramatically increase the bubble number density in a degassing silicic magma compared to the same magma without nanolites. The experiments were conducted using both nanolite-free and nanolite-bearing rhyolitic glass with different low initial water content. Using an Optical Dilatometer at 1 bar ambient pressure, cylindrical samples were heated at variable rates (1-30 °C min<sup>-1</sup>) to final temperatures of 820-1000 °C. This method allowed us to continuously monitor the volume, and hence porosity evolution in time. X-ray computed microtomography (µCT) and Scanning Electron Microscope (SEM) analyses revealed low and high bubble number densities for the nanolite-free and nanolite-bearing samples respectively.</p><p>Comparing vesicle number densities of natural volcanic rocks from explosive eruptions and our experimental results, we speculate that some very high naturally occurring bubble number densities could be associated with nanolites. We use a magma ascent model with P-T-H<sub>2</sub>O starting conditions relevant for known silicic eruptions to further underpin that such an increase in bubble number density caused driven by the presence of nanolites can feasibly turn an effusive eruption to an eventually explosive behavior.</p>

Magma ascent rates in explosive eruptions: Constraints from H2O diffusion in melt inclusions

2008 ◽  
Vol 270 (1-2) ◽  
pp. 25-40 ◽  
Author(s):  
Madeleine C.S. Humphreys ◽  
Thierry Menand ◽  
Jon D. Blundy ◽  
Kevin Klimm
Keyword(s):  
Melt Inclusions ◽  
Magma Ascent ◽  
Explosive Eruptions

scholarly journals Near-real-time volcanic cloud monitoring: insights into global explosive volcanic eruptive activity through analysis of Volcanic Ash Advisories

2021 ◽  
Vol 83 (2) ◽  
Author(s):  
S. Engwell ◽  
L. Mastin ◽  
A. Tupper ◽  
J. Kibler ◽  
P. Acethorp ◽  
...  
Keyword(s):  
Real Time ◽  
Volcanic Activity ◽  
Volcanic Ash ◽  
Source Parameters ◽  
Volcanic Eruptions ◽  
Volcanic Hazards ◽  
Process Data ◽  
Cloud Monitoring ◽  
Satellite Sensors ◽  
Volcanic Cloud

AbstractUnderstanding the location, intensity, and likely duration of volcanic hazards is key to reducing risk from volcanic eruptions. Here, we use a novel near-real-time dataset comprising Volcanic Ash Advisories (VAAs) issued over 10 years to investigate global rates and durations of explosive volcanic activity. The VAAs were collected from the nine Volcanic Ash Advisory Centres (VAACs) worldwide. Information extracted allowed analysis of the frequency and type of explosive behaviour, including analysis of key eruption source parameters (ESPs) such as volcanic cloud height and duration. The results reflect changes in the VAA reporting process, data sources, and volcanic activity through time. The data show an increase in the number of VAAs issued since 2015 that cannot be directly correlated to an increase in volcanic activity. Instead, many represent increased observations, including improved capability to detect low- to mid-level volcanic clouds (FL101–FL200, 3–6 km asl), by higher temporal, spatial, and spectral resolution satellite sensors. Comparison of ESP data extracted from the VAAs with the Mastin et al. (J Volcanol Geotherm Res 186:10–21, 2009a) database shows that traditional assumptions used in the classification of volcanoes could be much simplified for operational use. The analysis highlights the VAA data as an exceptional resource documenting global volcanic activity on timescales that complement more widely used eruption datasets.

scholarly journals The vertical distribution of volcanic SO<sub>2</sub> plumes measured by IASI

2016 ◽  
Vol 16 (7) ◽  
pp. 4343-4367 ◽  
Author(s):  
Elisa Carboni ◽  
Roy G. Grainger ◽  
Tamsin A. Mather ◽  
David M. Pyle ◽  
Gareth E. Thomas ◽  
...  
Keyword(s):  
Volcanic Eruptions ◽  
Maximum Amount ◽  
The Other ◽  
High Spectral Resolution ◽  
Explosive Eruptions ◽  
Atmospheric Processes ◽  
Atmospheric Sounding ◽  
Volcanic Emission ◽  
The Vertical Distribution ◽  
Atmospheric Constituent

Abstract. Sulfur dioxide (SO2) is an important atmospheric constituent that plays a crucial role in many atmospheric processes. Volcanic eruptions are a significant source of atmospheric SO2 and its effects and lifetime depend on the SO2 injection altitude. The Infrared Atmospheric Sounding Interferometer (IASI) on the METOP satellite can be used to study volcanic emission of SO2 using high-spectral resolution measurements from 1000 to 1200 and from 1300 to 1410 cm−1 (the 7.3 and 8.7 µm SO2 bands) returning both SO2 amount and altitude data. The scheme described in Carboni et al. (2012) has been applied to measure volcanic SO2 amount and altitude for 14 explosive eruptions from 2008 to 2012. The work includes a comparison with the following independent measurements: (i) the SO2 column amounts from the 2010 Eyjafjallajökull plumes have been compared with Brewer ground measurements over Europe; (ii) the SO2 plumes heights, for the 2010 Eyjafjallajökull and 2011 Grimsvötn eruptions, have been compared with CALIPSO backscatter profiles. The results of the comparisons show that IASI SO2 measurements are not affected by underlying cloud and are consistent (within the retrieved errors) with the other measurements. The series of analysed eruptions (2008 to 2012) show that the biggest emitter of volcanic SO2 was Nabro, followed by Kasatochi and Grímsvötn. Our observations also show a tendency for volcanic SO2 to reach the level of the tropopause during many of the moderately explosive eruptions observed. For the eruptions observed, this tendency was independent of the maximum amount of SO2 (e.g. 0.2 Tg for Dalafilla compared with 1.6 Tg for Nabro) and of the volcanic explosive index (between 3 and 5).

scholarly journals Assessing the impact of explosive eruptions of Fogo volcano (São Miguel, Azores) on the tourism economy

2021 ◽  
Vol 21 (1) ◽  
pp. 417-437
Author(s):  
Joana Medeiros ◽  
Rita Carmo ◽  
Adriano Pimentel ◽  
José Cabral Vieira ◽  
Gabriela Queiroz
Keyword(s):  
Economic Impact ◽  
Economic Loss ◽  
Volcanic Hazards ◽  
Plinian Eruption ◽  
Explosive Eruptions ◽  
Density Currents ◽  
Economic Sectors ◽  
Worst Case ◽  
The Impact ◽  
Fogo Volcano

Abstract. The Azores are an active volcanic region that offers exceptional conditions for nature-based tourism, one of the main axes of economic growth in the archipelago. A future volcanic eruption may have long-term consequences to this economic sector. Therefore, it is fundamental to assess its vulnerability to volcanic hazards in order to try to mitigate the associated risk. This study proposes a new approach to assessing the economic impact of explosive eruptions on the tourism sector. We considered two eruptive scenarios for Fogo volcano (São Miguel Island), the most probable (Volcanic Explosivity Index, VEI, 4 sub-Plinian eruption) and the worst-case (VEI 5 Plinian eruption), both producing tephra fallout and pyroclastic density currents. The results of numerical simulations were overlaid with tourism-related buildings and infrastructure of Vila Franca do Campo municipality to identify the elements at risk. The loss present value method was used to estimate the benefits generated by the accommodation units over 30 years for different economic scenarios. The assessment of the economic impact using 2018 indicators reveals that in a near-total-destruction scenario, the economic loss is approximately EUR 145 million (considering a 2 % discount rate). This approach can also be applied to other volcanic regions, geologic hazards and economic sectors.

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