SO2 flux from Stromboli during the 2007 eruption: Results from the FLAME network and traverse measurements

Abstract SO2 fluxes emitted by Stromboli during the 27th February–2nd April 2007 effusive eruption were regularly measured both by an automatic network of scanning ultraviolet spectrometers and by traverse measurements conducted by boat and helicopter. The results from both methodologies agree reasonably well, providing a validation for the automatic flux calculations produced by the network. Approximately 22,000 t of SO2 were degassed during the course of the 35 day eruption at an average rate of 620 t per day. Such a degassing rate is much higher than that normally observed (150–200 t/d), because the cross-sectional area occupied by ascending degassed magma is much greater than normal during the effusion, as descending, degassed magma that would normally occupy a large volume of the conduit is absent. We propose that the hydrostatically controlled magma level within Stromboli's conduit is the main control on eruptive activity, and that a high effusion rate led to the depressurisation of an intermediate magma reservoir, creating a decrease in the magma level until it dropped beneath the eruptive fissure, causing the rapid end of the eruption. A significant decrease in SO2 flux was observed prior to a paroxysm on 15th March 2007, suggesting that choking of the gas flowing in the conduit may have induced a coalescence event, and consequent rapid ascent of gas and magma that produced the explosion.

[1]  F. Giudicepietro,et al.  Source mechanisms of explosions at Stromboli Volcano, Italy, determined from moment‐tensor inversions of very‐long‐period data , 2003 .

[2]  P. Kyle,et al.  Open and almost shut case for explosive eruptions: Vent processes determined by SO2 emission rates at Karymsky volcano, Kamchatka , 2002 .

[3]  M. Rosi,et al.  The December 2002–July 2003 effusive event at Stromboli volcano, Italy: Insights into the shallow plumbing system by petrochemical studies , 2006 .

[4]  J. Sabroux,et al.  Forecasting volcanic events , 1983 .

[5]  A. Bertagnini,et al.  Stromboli volcano (Aeolian Archipelago, Italy): An open window on the deep-feeding system of a steady state basaltic volcano , 2003 .

[6]  A. McGonigle,et al.  A miniaturised ultraviolet spectrometer for remote sensing of SO2 fluxes: a new tool for volcano surveillance , 2003 .

[7]  Mike Burton,et al.  Novel retrieval of volcanic SO2 abundance from ultraviolet spectra , 2009 .

[8]  P. Tommasi,et al.  The evolution of the Sciara del Fuoco subaerial slope during the 2007 Stromboli eruption: Relation between deformation processes and effusive activity , 2009 .

[9]  Salvatore Gambino,et al.  Stromboli 2007 eruption: Deflation modeling to infer shallow‐intermediate plumbing system , 2008 .

[10]  E. Marchetti,et al.  Volcanic and Seismic Activity at Stromboli Preceding the 2002-2003 Flank Eruption , 2008 .

[11]  A. Bertagnini,et al.  Onset of the persistent activity at Stromboli Volcano (Italy) , 2000 .

[12]  L. Malinconico.  On the variation of SO2 emission from volcanoes , 1987 .

[13]  M. Ripepe,et al.  Effusive to explosive transition during the 2003 eruption of Stromboli volcano , 2005 .

[14]  L. Civetta,et al.  Magma dynamics during the 2007 Stromboli eruption (Aeolian Islands, Italy): Mineralogical, geochemical and isotopic data , 2009 .

[15]  Mike Burton,et al.  Magmatic Gas Composition Reveals the Source Depth of Slug-Driven Strombolian Explosive Activity , 2007, Science.

[16]  Tommaso Caltabiano,et al.  SO2 flux measurements at Mount Etna (Sicily) , 1994 .

[17]  T. Caltabiano,et al.  Continuous soil CO2 and discrete plume SO2 measurements at Mt. Etna (Italy) during 1997–2000: a contribution to volcano monitoring , 2004 .

[18]  Sune Svanberg,et al.  Monitoring of volcanic sulphur dioxide emissions using differential absorption lidar (DIAL), differential optical absorption spectroscopy (DOAS), and correlation spectroscopy (COSPEC) , 1998 .

[19]  F. Innocenti,et al.  Evolution of Eolian arc volcanism (Southern Tyrrhenian Sea) , 1974 .

[20]  C. Oppenheimer,et al.  Endogenous growth of persistently active volcanoes , 1993, Nature.

[21]  A. J. Sutton,et al.  Implications for eruptive processes as indicated by sulfur dioxide emissions from Kı̄lauea Volcano, Hawai‘i, 1979–1997 , 2001 .

[22]  S. Ciliberto,et al.  Time constraints for modeling source dynamics of volcanic explosions at Stromboli , 2001 .

[23]  Sune Svanberg,et al.  Optical monitoring of volcanic sulphur dioxide emissions - comparison between four different remote-sensing spectroscopic techniques , 2002 .

[24]  P. Zettwoog,et al.  Sulphur output and magma degassing budget of Stromboli volcano , 1994, Nature.

[25]  L. Francalanci,et al.  Intra-Grain Sr Isotope Evidence for Crystal Recycling and Multiple Magma Reservoirs in the Recent Activity of Stromboli Volcano, Southern Italy , 2005 .

[26]  Paolo Papale,et al.  The 2007 eruption of Stromboli volcano: Insights from real-time measurement of the volcanic gas plume CO2/SO2 ratio , 2009 .

[27]  Clive Oppenheimer,et al.  Automated, high time-resolution measurements of SO2 flux at Soufrière Hills Volcano, Montserrat , 2003 .

[28]  R. Scarpa,et al.  Correction to “Source mechanisms of explosions at Stromboli Volcano, Italy, determined from moment-tensor inversions of very-long-period data” , 2003 .

[29]  M. Burton,et al.  The role of gas percolation in quiescent degassing of persistently active basaltic volcanoes , 2007 .