Evolution of volcanic gas composition during repeated culmination of volcanic activity at Kuchinoerabujima volcano, Japan

2011 ◽  
Vol 202 (1-2) ◽  
pp. 107-116 ◽  
Author(s):  
H. Shinohara ◽  
J. Hirabayashi ◽  
K. Nogami ◽  
M. Iguchi
2020 ◽  
Author(s):  
Brendan McCormick Kilbride ◽  
Emma Liu ◽  
Kieran Wood ◽  
Thomas Wilkes ◽  
Ian Schipper ◽  
...  

<p>Bagana volcano, Papua New Guinea, is among Earth’s youngest and most active volcanoes. Bagana typically exhibits multi-year episodes of lava extrusion, interspersed with pause periods characterised by strong passive degassing. Based on satellite-based observations, Bagana is the third ranked global source of volcanic sulfur dioxide over the past 15 years. Recent work based on global correlations between volcanic gas composition and magma trace element chemistry has predicted that it may be the fifth ranked global volcanic deep carbon source. However, this indirect estimate of Bagana’s potential carbon budget has yet to be ground-truthed by in-situ sampling.</p><p>We visited Bagana in September 2019 and made the first measurements of the chemical composition of the volcano’s summit gas plume. We placed a miniaturized MultiGAS sensor array on board an unoccupied aerial system (UAS, or drone) and flew the sensors through the plume. Our aircraft flew beyond visual line of sight, reaching the gas plume from around 7 km horizontal distance and 2 km altitude below the summit. Such long-range UAS flights offer immense potential for studying gas emissions from such steep, active or remote volcanoes.</p><p>Our MultiGAS flights found relatively low concentrations of both sulfur dioxide and carbon dioxide in the Bagana plume. Moreover, we made coincident remote sensing measurements of sulfur dioxide emissions using ground- and UAS-based ultraviolet spectroscopy and calculated SO2 fluxes of only ~400 tonnes per day. These are an order of magnitude below the typical fluxes inferred from satellite observations. Combining MultiGAS plume composition (CO2/SO2 molar ratio, mean ~3.4) and SO2 fluxes allow us to estimate Bagana’s CO2 flux into the atmosphere as only ~1360 t/d.</p><p>Our interpretation of these results is that the volcano is presently in a low state of activity. From satellite observations, we note the cessation of the most recent extrusive episode several weeks prior to our field campaign. The lack of the anticipated strong passive degassing often observed by spaceborne UV sensors is likely a result of “scrubbing” in the volcanic edifice, where rising gases interact with groundwater, resulting in dissolution of sulfur species into the groundwater and perhaps precipitation of sulfur-bearing minerals into edifice fractures. As the volcano moves towards a future extrusive episode, we might anticipate the gradual drying out of the hydrothermal system and a shift towards more truly magmatic gas compositions. Our results show that short campaign measurements may not provide data which are representative of a volcano’s longterm behaviour and we suggest that caution is needed in using such data to calculate or extrapolate regional and global volatile emissions inventories.</p>


2015 ◽  
Vol 303 ◽  
pp. 199-208 ◽  
Author(s):  
Hiroshi Shinohara ◽  
Takao Ohminato ◽  
Minoru Takeo ◽  
Hiroshi Tsuji ◽  
Ryunosuke Kazahaya

2019 ◽  
Vol 81 (2) ◽  
Author(s):  
Ryunosuke Kazahaya ◽  
Hiroshi Shinohara ◽  
Takao Ohminato ◽  
Takayuki Kaneko

Geology ◽  
2007 ◽  
Vol 35 (12) ◽  
pp. 1115 ◽  
Author(s):  
Alessandro Aiuppa ◽  
Roberto Moretti ◽  
Cinzia Federico ◽  
Gaetano Giudice ◽  
Sergio Gurrieri ◽  
...  

2020 ◽  
Vol 407 ◽  
pp. 107098
Author(s):  
H. Shinohara ◽  
R. Kazahaya ◽  
T. Ohminato ◽  
T. Kaneko ◽  
U. Tsunogai ◽  
...  

2020 ◽  
Vol 10 (20) ◽  
pp. 7293
Author(s):  
Joao Lages ◽  
Yves Moussallam ◽  
Philipson Bani ◽  
Nial Peters ◽  
Alessandro Aiuppa ◽  
...  

Recent volcanic gas compilations have urged the need to expand in-situ plume measurements to poorly studied, remote volcanic regions. Despite being recognized as one of the main volcanic epicenters on the planet, the Vanuatu arc remains poorly characterized for its subaerial emissions and their chemical imprints. Here, we report on the first plume chemistry data for Mount Garet, on the island of Gaua, one of the few persistent volatile emitters along the Vanuatu arc. Data were collected with a multi-component gas analyzer system (multi-GAS) during a field campaign in December 2018. The average volcanic gas chemistry is characterized by mean molar CO2/SO2, H2O/SO2, H2S/SO2 and H2/SO2 ratios of 0.87, 47.2, 0.13 and 0.01, respectively. Molar proportions in the gas plume are estimated at 95.9 ± 11.6, 1.8 ± 0.5, 2.0 ± 0.01, 0.26 ± 0.02 and 0.06 ± 0.01, for H2O, CO2, SO2, H2S and H2. Using the satellite-based 10-year (2005–2015) averaged SO2 flux of ~434 t d−1 for Mt. Garet, we estimate a total volatile output of about 6482 t d−1 (CO2 ~259 t d−1; H2O ~5758 t d−1; H2S ~30 t d−1; H2 ~0.5 t d−1). This may be representative of a quiescent, yet persistent degassing period at Mt. Garet; whilst, as indicated by SO2 flux reports for the 2009–2010 unrest, emissions can be much higher during eruptive episodes. Our estimated emission rates and gas composition for Mount Garet provide insightful information on volcanic gas signatures in the northernmost part of the Vanuatu Arc Segment. The apparent CO2-poor signature of high-temperature plume degassing at Mount Garet raises questions on the nature of sediments being subducted in this region of the arc and the possible role of the slab as the source of subaerial CO2. In order to better address the dynamics of along-arc volatile recycling, more volcanic gas surveys are needed focusing on northern Vanuatu volcanoes.


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