Project

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Fragmentation efficiency of mafic magmas

Applicant Pioli Laura
Number 162439
Funding scheme Project funding
Research institution Département des sciences de la Terre Université de Genève
Institution of higher education University of Geneva - GE
Main discipline Mineralogy
Start/End 01.05.2016 - 31.08.2020
Approved amount 280'784.00
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Keywords (4)

Physical volcanology; Natural Hazards; Explosive volcanism; Etna

Lay Summary (Italian)

Lead
Perché un’eruzione basaltica può essere fortemente esplosiva? Le eruzioni basaltiche vengono normalmente descritte come poco energetiche, e associate solo a colate e fontane di lava. In realtà in molti vulcani, seppur a condotto aperto, si hanno eruzioni esplosive con formazione di particelle di lava (scorie, ceneri) di piccola dimensione che vengono trasportate a centinaia di km di distanza. La ricerca analizzerà le condizioni di frammentazione del magma per produrre un modello capace di prevedere la taglia delle particelle emesse durante eventi eruttivi.
Lay summary

Soggetto e obiettivi

Verranno eseguiti esperimenti per comprendere come la taglia delle particelle vari in relazione alla dinamica eruttiva e alle caratteristiche del magma eruttato. In oltre si studieranno eruzioni dell’Etna, un vulcano italiano molto attivo (e un eccellente laboratorio naturale). Per queste eruzioni, ben monitorate con l’ausilio di tecniche geofisiche, geochimiche e di remote sensing, saranno calcolati i parametri eruttivi (tasso di emissione del magma, caratteristiche delle scorie e loro distribuzione di taglia). I dati ottenuti saranno usati per la validazione del modello di frammentazione, ma anche per creare un database specifico per quantificare l’esplosività di questo vulcano, che si trova in una zona densamente abitata.

 

Contesto scientifico e sociale

Le eruzioni basaltiche, hanno mediamente intensità minori di quelle silicee, ma avvengono molto frequentemente, e per questo la pericolosità e il rischio a loro associati sono molto alti. Per esempio, tutti i vulcani più attivi in Europa sono basaltici e hanno avuto numerose eruzioni esplosive negli ultimi dieci anni. Queste eruzioni sono spesso di lunga durata (fino a settimane e mesi) causano perdite economiche talvolta ingenti, legate a chiusura del traffico aereo, di aeroporti, danni alle colture e alla salute di persone ed animali.

I risultati di questo progetto potranno essere usati direttamente per la quantificazione del rischio associato al vulcanismo esplosivo, e permetteranno l’implementazione di strategie per la riduzione del rischio.

Direct link to Lay Summary Last update: 30.09.2015

Responsible applicant and co-applicants

Employees

Name Institute

Publications

Publication
Magma fragmentation and particle size distributions in low intensity mafic explosions: the July/August 2015 Piton de la Fournaise eruption
Edwards Matthew J., Pioli Laura, Harris Andrew J. L., Gurioli Lucia, Thivet Simon (2020), Magma fragmentation and particle size distributions in low intensity mafic explosions: the July/August 2015 Piton de la Fournaise eruption, in Scientific Reports, 10(1), 13953-13953.
Reliability of Total Grain-Size Distribution of Tephra Deposits
Pioli L., Bonadonna C., Pistolesi M. (2019), Reliability of Total Grain-Size Distribution of Tephra Deposits, in Scientific Reports, 9(1), 10006-10006.
Real-Time Geophysical Monitoring of Particle Size Distribution During Volcanic Explosions at Stromboli Volcano (Italy)
Pioli Laura, Harris Andrew J. L. (2019), Real-Time Geophysical Monitoring of Particle Size Distribution During Volcanic Explosions at Stromboli Volcano (Italy), in Frontiers in Earth Science, 7, 52.
Subplinian monogenetic basaltic eruption of Sunset Crater, Arizona, USA
Alfano Fabrizio, Ort Michael H., Pioli Laura, Self Stephen, Hanson Sarah L., Roggensack Kurt, Allison Chelsea M., Amos Robert, Clarke Amanda B. (2018), Subplinian monogenetic basaltic eruption of Sunset Crater, Arizona, USA, in GSA Bulletin, 131(3-4), 661-674.
Shallow factors controlling the explosivity of basaltic magmas: The 17–25 May 2016 eruption of Etna Volcano (Italy)
Edwards Matthew John, Pioli Laura, Andronico Daniele, Scollo Simona, Ferrari Ferruccio, Cristaldi Antonio (2018), Shallow factors controlling the explosivity of basaltic magmas: The 17–25 May 2016 eruption of Etna Volcano (Italy), in Journal of Volcanology and Geothermal Research, 357, 425-436.

Datasets

Magma and tephra characteristics for the 17–25 May 2016 Mt Etna eruption

Author Edwards, M.J.; Pioli, L.
Publication date 01.02.2019
Persistent Identifier (PID) doi: 10.1016/j.dib.2018.11.093
Repository Data in brief
Abstract
This is the dataset associated with the research data article“Shallow factors controlling the explosivity of basaltic magmas: The17-25 May 2016 eruption of Etna Volcano (Italy)”Edwards et al. Thisdataset contains major element data for groundmass glass, plagioclase,olivine and clinopyroxene phenocrysts, and melt inclusions withinthese phenocrysts, found within tephra and lava from this eruption.We also provide the grain size dataset from the fallout deposits.

Collaboration

Group / person Country
Types of collaboration
Prof. M Ichihara/Earthquake Research Institute Japan (Asia)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
M. Ort/University of Northern Arizona United States of America (North America)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
Dr. D. Andronico/INGV Catania Italy (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
Dr. S.Scollo/INGV Catania Italy (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
A. Harris/Laboratoire Magmas et volcans, Clermont Ferrand France (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
M. Pistolesi/University of Pisa Italy (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
AGU Fall Meeting Talk given at a conference Real time assessment of particle size distribution in volcanic jet by thermal monitoring: potential and limitations of a low cost and fast processing method. 09.12.2019 San Francisco, United States of America Edwards Matthew; Pioli Laura;
AGu Fall Meeting Talk given at a conference A model for basaltic magma jet fragmentation 09.12.2019 San Francisco, United States of America Edwards Matthew; Pioli Laura;
COV 10 Talk given at a conference Magma fragmentation of low viscosity Strombolian explosions at Piton de la Fournaise volcano 02.09.2018 Naples, Italy Pioli Laura; Edwards Matthew;
COV 10 Poster Real-time geophysical monitoring of grainsize distributions during volcanic explosions 02.09.2018 Naples, Italy Pioli Laura;
AGU Fall meeting Talk given at a conference Fragmentation efficiency of low viscosity magmas: which mechanisms control ash formation? 11.12.2017 New Orleans, United States of America Edwards Matthew; Pioli Laura;
15th Swiss Geoscience Meeting Poster Mafic magma fragmentation and eruption dynamics of the May 2016 Etna eruption 17.11.2017 Davos, Switzerland Pioli Laura; Edwards Matthew;
EGU meeting Talk given at a conference Preliminary insights into a model for mafic magma fragmentation 23.04.2017 Vienna, Austria Pioli Laura; Edwards Matthew;
14 th Swiss Geoscience Meeting Poster Characterising the May 2016 eruption of Mt Etna, Italy. 18.11.2016 Geneva, Switzerland Edwards Matthew; Pioli Laura;
26th Goldschmidt meeting Talk given at a conference Dynamic effects of magma degassing 26.06.2016 Yokohama, Japan Pioli Laura;


Self-organised

Title Date Place
Linking magmatic fragmentation to explosive styles and eruption intensities 07.09.2018 Naples, Meeting Cities on Volcanoes, Italy

Abstract

Fragmentation of mafic magmas is generally believed to be poorly efficient, due to the low viscosity of these magmas (Parfitt, 1998), with increasing proportion of fine material being produced by magma-water interaction (Wohletz, 1986; Zimanovski et al., 1997). Key factors in controlling magma fragmentation are the magma properties (melt and bulk viscosity, crystallinity and vesicularity) and the flow regime, but the exact relationships are still largely unknown. Both small (Strombolian) and large (violent Strombolian to Subplinian and Plinian) explosions can produce very variable amounts of fine material (Jones et al, 2008), even when fragmentation processes are purely magmatic; this means that fragmentation of low viscosity magmas is still a poorly understood process, and actual conditions required to allow for efficient fragmentation have not yet been fully explored. Mafic magmas can undergo both brittle and inertially-driven (ductile) fragmentation, depending on their crystallinity, exsolved and dissolved gas content, and the eruption dynamics (Namiki and Manga, 2008; Gonnermann and Manga, 2012). At the moment, no specific models exist on inertially-driven fragmentation, and it is not possible to differentiate the fragmentation dynamics in mild explosivity (Hawaiian and Strombolian) eruptions and larger explosivity (violent Strombolian to Plinian and Subplinian) events, or to model it based on expected eruption conditions. This project will address these issues combining specific fluid dynamic experiments aimed at the quantification of the ductile fragmentation regime in magmatic jets and quantify its efficiency (median size and the shape of the size distribution of particles formed) in terms of flow dynamics and magma properties. Experimental activities on ductile fragmentation of liquid suspensions and bubbly liquids will focus on the size distribution of droplets formed at different flow regimes and the role of textural properties of the magma on controlling the fragmentation dynamics. The experiments will be validated with a comprehensive dataset on real eruptions of different styles and magnitude (eruption intensity and magnitude, total grainsize distribution of erupted material, vesicularity, bubble size distribution and number density, crystallinity of scoria). Eruption studies will focus on the most active European volcano: Mt. Etna (Italy). Etna constitutes an excellent natural laboratory not only because of the frequency of its eruptions but also because of their tremendous variability: from effusive to Hawaiian-Strombolian, but also Subplinian and Plinian (Branca and Del Carlo, 2005; Scollo et al., 2013). Moreover, continuous geophysical and geochemical monitoring allow for quantification of essential eruptive parameters, which will be fundamental for the research.Intellectual merit. Scaling of the experimental results and comparison with the volcanic dataset will allow for modeling of the expected grainsize distribution formed in specific eruptive conditions and magma properties, evaluate the relative role of ductile vs. brittle fragmentation and its variability in different explosive styles (Hawaiian, Strombolian to violent Strombolian).Broader impact. Outcomes from this project could be applied to volcano monitoring and quantification of hazard associated to explosive mafic volcanism. Only in the last decades, these eruptions have been causing huge losses at the global level because of crops damages, airport and air-space closures, and health problems.
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