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Two phase flow regimes in low viscosity magmas

English title Two phase flow regimes in low viscosity magmas
Applicant Bonadonna Costanza
Number 122268
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 Geophysics
Start/End 01.11.2008 - 31.10.2010
Approved amount 241'219.00
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Keywords (12)

Basaltic Volcanism; Explosive Volcanism; Eruption dynamics; Conduit flow dynamics; Modeling; Coalescence; low-viscosity systems; Stromboli volcano; Villarrica volcano; analogue experiments; dynamics of volcanic conduits; magma fragmentation

Lay Summary (English)

Lead
Lay summary
This project focuses on the investigation of magma rise and fragmentation dynamics in explosive eruptions of basaltic magma. Basaltic explosive activity includes a wide spectrum of phenomena ranging from rather continuous lava fountaining with fallout of molten lava clots around the vent (Hawaiian activity), to higher explosivity events, forming plumes up to several km high (Violent Strombolian to Subplinian and Plinian activities) and characterized by more efficient magma fragmentation. Transitional activity, characterized by intermittent to contemporaneous effusive and explosive activity, several seconds to hours-scale fluctuations of the explosion intensity, with formation of both lava fountains and weak, ash-laden plumes, is also common in hydrous basalts. Gas segregation and two-phase flow processes play a fundamental role in the eruptive dynamics.In this project we will compare field and experimental data to constrain magmatic flow in the conduit and the conditions leading to fragmentation of basaltic magma. We will focus on two very active volcanoes: Stromboli (Italy) and Villarrica (Chile). These volcanoes are in persistent activity and represent two exceptional natural laboratories to investigate explosive processes at basaltic volcanoes. We will perform experiments to reproduce a range of eruptive conditions and to compare our results with observations of natural systems (field and geophysical data). We will compare geophysical (acoustic, thermal) data, pyroclast features and experiments to constrain conduit flow and eruptive parameters. Our experiments will investigate the dynamics of magma rise in the conduit and how these processes affect the eruption dynamics. In particular, we will explore: i) the effect of the entrance conditions on the flow dynamics, ii) the effects of the conduit geometry on the flow dynamics, iii) the conditions for the formation of bubble rich (foam) layers in the conduit and iv) the stability and characteristics of different flow regimes and transition mechanisms of low-viscosity systems. We will also monitor the activity and study selected eruptions and the characteristics of the erupted pyroclasts from the two selected volcanoes to obtain flow parameter and variability of eruptive conditions. The main goal of our project is to produce a complete dataset for the compilation of a model for conduit dynamics of low-viscosity systems crucial to our understanding of basaltic volcanoes and to the assessment of the associated hazard. This project will be supported by an international team, comprising scientists from the universities of Geneva, Florence, Pisa (Italy), Nottingham and Bristol (UK).
Direct link to Lay Summary Last update: 21.02.2013

Responsible applicant and co-applicants

Employees

Publications

Publication
Experimental constraints on the outgassing dynamics of basaltic magmas
Pioli L., Bonadonna C., Azzopardi B. J., Phillips J. C., Ripepe M. (2012), Experimental constraints on the outgassing dynamics of basaltic magmas, in Journal of Geophysical Research: Solid Earth, 117(B3), B03204.
Monochromatic infrasonic tremor driven by persistent degassing and convection at Villarrica Volcano, Chile
Ripepe M., Marchetti E., Bonadonna C., Harris A. J. L., Pioli L., Ulivieri G. (2010), Monochromatic infrasonic tremor driven by persistent degassing and convection at Villarrica Volcano, Chile, in Geophysical Research Letters, 37(15), L15303.
Controls on the explosivity of scoria cone eruptions: Magma segregation at conduit junctions
Pioli L., Azzopardi B.J., Cashman K.V. (2009), Controls on the explosivity of scoria cone eruptions: Magma segregation at conduit junctions, in Journal of Volcanology and Geothermal Research, 186(3-4), 407-415.

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
EGU General Assembly 2010 Talk given at a conference Gas transport and vesicularity in low viscosity liquids 02.05.2010 Vienna, Austria Pioli Laura; Bonadonna Costanza;
AGU Fall meeting 2009 Talk given at a conference Infrasonic tremor driven by lava lake degassing at Villarrica Volcano, Chile 14.12.2009 San Francisco, United States of America Pioli Laura; Bonadonna Costanza;
AGU Fall meeting 2009 Talk given at a conference Open system degassing, bubble rise and the flow dynamics within a volcanic conduit - an experimental approach 14.12.2009 San Francisco, United States of America Bonadonna Costanza; Pioli Laura;


Communication with the public

Communication Title Media Place Year
Talks/events/exhibitions Looking deep into model volcanoes. Royal Society Summer Science exhibition, London (UK) International 2010

Associated projects

Number Title Start Funding scheme
132543 Two-phase flows of low-viscosity magmas 01.11.2010 Project funding

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