The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Hiroshi Shinohara - One of the best experts on this subject based on the ideXlab platform.
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variation of Volcanic Gas composition at a poorly accessible volcano sakurajima japan
Journal of Volcanology and Geothermal Research, 2020Co-Authors: Hiroshi Shinohara, Ryunosuke Kazahaya, Takao Ohminato, Takayuki Kaneko, Urumu Tsunogai, M MoritaAbstract:Abstract Volcanic Gas compositions are estimated based on Volcanic plume measurement with Multi-Gas at a frequently erupting Sakurajima volcano by application of airborne methods and automatic monitoring station on the flank during 2013–2019. The airborne measurements of CO2 and H2O concentrations often suffer from large fluctuation of background likely due to entrainment of the atmosphere derived from different altitude. By removing the background effect, a representative Volcanic CO2/SO2 mole ratio is estimated as 0.4 ± 0.1 and we did not observe clear temporal variation. The Volcanic H2O/SO2 ratios are estimated as 30–70 with a large uncertainty because of the strong atmospheric perturbation. The SO2/H2S ratios show quite a large variation ranging from 1 to 800. The large SO2/H2S ratios larger than 30 are observed during ash eruption and are suggested as a result of oxidation by atmosphere on hot ashes. The small ratios less than 10 are observed when frequency of explosions is low. Variation of the SO2/H2S ratios of the small values can be caused by variation of deGassing pressure, however, the small variation of the CO2/SO2 ratio suggests a limited range of the pressure variation.
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Airborne measurements of Volcanic Gas composition during unrest at Kuchinoerabujima volcano, Japan
Bulletin of Volcanology, 2019Co-Authors: Ryunosuke Kazahaya, Hiroshi Shinohara, Takao Ohminato, Takayuki KanekoAbstract:Airborne measurements of Volcanic Gas composition using an unmanned aerial vehicle (UAV) and Cessna aircraft were conducted at Kuchinoerabujima volcano, Japan, between 2014 and 2016. Because eruptions occurred in August 2014, May 2015, and June 2015, access to the summit crater was limited because of the risk of sudden eruption such that airborne measurements were the only viable method to measure the Volcanic Gas composition. Multi-Gas and alkali-filter pack measurements were made on the leeward side of the crater and around the crater, using the Cessna and UAV, respectively. Observations using the UAV could measure the dense plume and quantify the Gas species of H2O, CO2, SO2, H2S, H2, HCl, and HF, while the observations using the Cessna could measure only the diluted plume and quantify CO2, SO2, H2S, and H2. The seven airborne observations enabled us to monitor variations in the Volcanic Gas composition. Over the observation period, the SO2/H2S ratio decreased from 10 to 1.9. The H2O/SO2 ratio, H2/SO2 ratio, and apparent equilibrium temperatures (AET) estimated using the Volcanic Gas composition increased after the 2014 eruption. The decrease in the SO2/H2S ratio might be attributed to changes in the pressure of deGassing magma and interactions with the hydrothermal system. The airborne methods presented here highlight the utility of using light aircrafts to safely conduct Volcanic Gas measurements during periods of Volcanic unrest when traditional ground-based methods are not possible.
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variation of Volcanic Gas composition during the eruptive period in 2014 2015 at nakadake crater aso volcano japan
Earth Planets and Space, 2018Co-Authors: Hiroshi Shinohara, Akihiko Yokoo, Ryunosuke KazahayaAbstract:Volcanic Gas composition measurement by Multi-Gas was repeated during the eruptive period in 2014–2015 as well as the quiet period preceding the eruption at Nakadake crater, Aso volcano. The eruptive activity is characterized by continuous ash emission with intermittent Strombolian activity and temporal pauses. Volcanic Gas composition measured during the eruptive period showed a rapid and large variation. In particular, the CO2/SO2 and SO2/H2S ratios varied in the rages of 1–8 and 3–300 during the ash eruption with a clear negative correlation. The large variation and the negative correlation of the compositions are attributed to two orders of magnitude difference of deGassing pressure, such as 20 and 0.2 MPa; the Gases with the large CO2/SO2 and the small SO2/H2S ratios are derived from the high pressure. The rapid and large composition variation suggests frequent ascent of bubbles formed at various depth during the eruption. The maximum CO2/SO2 ratio decreased with decreasing eruption intensity that suggests decrease in contribution of the bubbles derived from a large depth. With time, H2O/SO2 ratio of the Gases increases from 30 to > 60, suggesting increase in a hydrothermal contribution.
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monitoring of Volcanic Gas composition at asama volcano japan during 2004 2014
Journal of Volcanology and Geothermal Research, 2015Co-Authors: Hiroshi Shinohara, Takao Ohminato, Minoru Takeo, Hiroshi Tsuji, Ryunosuke KazahayaAbstract:Abstract The composition of the Volcanic Gases discharged from the summit crater of Asama volcano has been monitored since 2004 by Multi-Gas and alkaline-filter techniques. The persistent deGassing activity at Asama volcano is characterized by large variation of SO 2 flux. The CO 2 /SO 2 and H 2 O/SO 2 ratios did not show clear variation irrespective of the SO 2 flux variation and a few eruptions that occurred during active deGassing periods. The estimated ratios have large uncertainty due to variable contribution of the different fumaroles in the summit crater to the Volcanic plume and lack of a systematic variation can be due to the large uncertainty. The SO 2 /Cl ratio showed a systematic decrease after the eruption to the inactive period, suggesting that deGassing pressure did not significantly increase after the eruption. Low-pressure deGassing along with the continuous and intensive Gas discharge suggests that the deGassing is due to conduit magma convection. The apparently stable CO 2 /SO 2 ratios imply a lack of significant volatile differentiation in the magma reservoir, such as CO 2 -rich bubble accumulation. The large variation of the SO 2 flux along with stable Gas composition implies that the large changes in magma convection rate are caused by changes in the radius of the convecting magma conduit.
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budget of shallow magma plumbing system at asama volcano japan revealed by ground deformation and Volcanic Gas studies
Journal of Geophysical Research, 2015Co-Authors: Ryunosuke Kazahaya, Yosuke Aoki, Hiroshi ShinoharaAbstract:Multiple cycles of the intensive Volcanic Gas discharge and ground deformation (inflation and deflation) were observed at Asama Volcano, Japan, from 2000 to 2011. Magma budget of the shallow magma plumbing system was estimated on the basis of the Volcanic Gas emission rates and ground deformation data. Recent inflations observed in 2004 and 2008 were modeled as a dike intrusion to 2–3 km west of Asama Volcano. Previous studies proposed that magma ascends from a midcrustal magma reservoir to the dike and reaches the surface via a sinuous conduit which connects the dike to the summit. The intensive Volcanic sulfur dioxide discharge of up to 4600 t/d at the volcano was modeled by magma convective deGassing through this magma pathway. The volcano deflates as shrinkage of the magma in a reservoir by Volcanic Gas discharge. We estimated the volume change of the dike modeled based on the GPS observations, the volume decrease of the magma by the Volcanic Gas discharge, and the amount of deGassed magma produced to calculate the magma budget. The results show that the volume decrease of the magma by the Volcanic Gas discharge was larger than the volume change of the dike during the inflation periods. This indicates that a significant volume of magma at least more than 2 times larger than the volume change of the dike was supplied from the midcrustal magma reservoir to the dike. The volume decrease of the dike was comparable with the volume decrease of the magma by the Volcanic Gas discharge during the deflation periods. The long-term deflation trend of the dike and the volume of deGassed magma (108–9 m3) suggest that the deGassed magma produced is not stored in the dike and the magma is mainly supplied from the midcrustal magma reservoir. In both periods, the volume of deGassed magma produced was 1 order of magnitude larger than the volume change of the dike. This indicates that the actual volume of the magma supplied from the midcrustal magma reservoir is up to 1 order of magnitude larger than the volume change of the dike. These results strongly suggest that an amount of magma moved through a magma reservoir is possible to be significantly larger than volume change of the magma reservoir estimated by the geodetic observations.
Alessandro Aiuppa - One of the best experts on this subject based on the ideXlab platform.
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aerial strategies advance Volcanic Gas measurements at inaccessible strongly deGassing volcanoes
Science Advances, 2020Co-Authors: Nicole Bobrowski, Santiago Arellano, Alessandro Aiuppa, Emma J Liu, A Alan, Marcello Bitetto, S A Carn, Robert ClarkeAbstract:Volcanic emissions are a critical pathway in Earth’s carbon cycle. Here, we show that aerial measurements of Volcanic Gases using unoccupied aerial systems (UAS) transform our ability to measure and monitor plumes remotely and to constrain global volatile fluxes from volcanoes. Combining multi-scale measurements from ground-based remote sensing, long-range aerial sampling, and satellites, we present comprehensive Gas fluxes—3760 ± [600, 310] tons day−1 CO2 and 5150 ± [730, 340] tons day−1 SO2—for a strong yet previously uncharacterized Volcanic emitter: Manam, Papua New Guinea. The CO2/ST ratio of 1.07 ± 0.06 suggests a modest slab sediment contribution to the sub-arc mantle. We find that aerial strategies reduce uncertainties associated with ground-based remote sensing of SO2 flux and enable near–real-time measurements of plume chemistry and carbon isotope composition. Our data emphasize the need to account for time averaging of temporal variability in Volcanic Gas emissions in global flux estimates.
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Volcanic Gas emissions and deGassing dynamics at ubinas and sabancaya volcanoes implications for the volatile budget of the central Volcanic zone
Journal of Volcanology and Geothermal Research, 2017Co-Authors: Yves Moussallam, Giancarlo Tamburello, Alessandro Aiuppa, Nial Peters, Fredy Apaza, Ian Schipper, Aaron Curtis, Pablo MasiasAbstract:Abstract Emission of Volcanic Gas is thought to be the dominant process by which volatiles transit from the deep earth to the atmosphere. Volcanic Gas emissions, remain poorly constrained, and volcanoes of Peru are entirely absent from the current global dataset. In Peru, Sabancaya and Ubinas volcanoes are by far the largest sources of Volcanic Gas. Here, we report the first measurements of the compositions and fluxes of Volcanic Gases emitted from these volcanoes. The measurements were acquired in November 2015. We determined an average SO 2 flux of 15.3 ± 2.3 kg s − 1 (1325-ton day − 1 ) at Sabancaya and of 11.4 ± 3.9 kg s − 1 (988-ton day − 1 ) at Ubinas using scanning ultraviolet spectroscopy and dual UV camera systems. In-situ Multi-Gas analyses yield molar proportions of H 2 O, CO 2 , SO 2 , H 2 S and H 2 Gases of 73, 15, 10 1.15 and 0.15 mol% at Sabancaya and of 96, 2.2, 1.2 and 0.05 mol% for H 2 O, CO 2 , SO 2 and H 2 S at Ubinas. Together, these data imply cumulative fluxes for both volcanoes of 282, 30, 27, 1.2 and 0.01 kg s − 1 of H 2 O, CO 2 , SO 2 , H 2 S and H 2 respectively. Sabancaya and Ubinas volcanoes together contribute about 60% of the total CO 2 emissions from the Central Volcanic zone, and dominate by far the total revised volatile budget of the entire Central Volcanic Zone of the Andes.
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along arc inter arc and arc to arc variations in Volcanic Gas co2 st ratios reveal dual source of carbon in arc volcanism
Earth-Science Reviews, 2017Co-Authors: Alessandro Aiuppa, Philippe Robidoux, Tobias Fischer, Terry Plank, Rossella Di NapoliAbstract:Abstract Some 300–600 Tg of volatiles are globally vented each year by arc volcanism. Such arc Gas emissions have contributed to past and present-day evolution of the Earth atmosphere and climate by recycling mineral-bound volatiles subducted along active slabs. Carbon dioxide (CO 2 ) and total sulphur (S T ) are, after water, the major components of Volcanic arc Gases. Understanding their relative abundances (e.g., the CO 2 /S T ratio) in arc Volcanic Gases is important to constrain origin and recycling efficiency of these volatiles along the subduction factory, and to better constrain the global arc Volcanic CO 2 flux. Here, we review currently available information on global variations of Volcanic arc CO 2 /S T Gas ratios. We analyse a dataset of > 2000 published Volcanic arc Gas measurements that comprise (i) low-temperature hydrothermal Gas emissions, in which S T is dominated by hydrothermal hydrogen sulphide (H 2 S), and (ii) high temperature “magmatic” Gases rich in sulphur dioxide (SO 2 ). We show that the global CO 2 /S T population of hydrothermal Gases is mainly controlled by S loss to hydrothermal fluids/rocks. We then select a subset of high-temperature (≥ 450 °C) arc Gases which, being less affected by S hydrothermal loss, can be used to infer the “deep” source of volatiles. Using a subset of time-averaged high-T Gas compositions for 56 arc volcanoes, we identify sizeable along-arc and inter-arc variations in the “magmatic” arc Gas CO 2 /S T ratio, which we ascribe to distinct volatile origins in the magma generation/storage zone. In the attempt to resolve the slab vs. crustal contributions to arc Gas budgets, we explore the global association between Volcanic Gas CO 2 /S T ratios and non-volatile (trace elements) tracers in arc magmas. For the first time in a global study, we find evidence for higher carbon output (CO 2 /S T ) in arcs where carbonate sediment subducts on the seafloor. Indeed, most arc volcanoes exhibit Gas vs. trace element relationships that are explained by addition of slab-sediment melts ± fluids to the mantle wedge. We also identify a subset of CO 2 -rich arc volcanoes with unusually high CO 2 /S T ratios (Etna, Stromboli, Vulcano Island, Popocatepetl, Soufriere of St Vincent, Bromo and Merapi), which we interpret as the product of magma-limestone interactions in the upper crust. Evidence for this process comes from carbonate xenoliths and/or carbonate basement that characterise these Volcanic systems. Although the mean global CO 2 /S T ratio of arc Gas (~ 2.5) reflects a predominant source from subducted sediment, limestone-assimilation-derived C may account for a substantial (~ 19–32%) fraction of the present-day global arc budget, and may have contributed to elevated atmospheric CO 2 levels and warmer climate in Earth's past. Our global CO 2 /S T vs. trace element association paves the way to identifying the Gas signature of volcanoes (or arc segments) for which Gas information is currently missing, and so improve our current global Volcanic arc CO 2 flux inventory.
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short period Volcanic Gas precursors to phreatic eruptions insights from poas volcano costa rica
Earth and Planetary Science Letters, 2016Co-Authors: Marco Liuzzo, Alessandro Aiuppa, J M De Moor, Michael E Martinez, Christoph Kern, J Pacheco, G Avard, Gaetano GiudiceAbstract:Abstract Volcanic eruptions involving interaction with water are amongst the most violent and unpredictable geologic phenomena on Earth. Phreatic eruptions are exceptionally difficult to forecast by traditional geophysical techniques. Here we report on short-term precursory variations in Gas emissions related to phreatic blasts at Poas volcano, Costa Rica, as measured with an in situ multiple Gas analyzer that was deployed at the edge of the erupting lake. Gas emitted from this hyper-acid crater lake approaches magmatic values of SO2/CO2 1–6 days prior to eruption. The SO2 flux derived from magmatic deGassing through the lake is measureable by differential optical absorption spectrometry (sporadic campaign measurements), which allows us to constrain lake Gas output and input for the major Gas species during eruptive and non-eruptive periods. We can further calculate power supply to the hydrothermal system using volatile mass balance and thermodynamics, which indicates that the magmatic heat flux into the shallow hydrothermal system increases from ∼27 MW during quiescence to ∼59 MW during periods of phreatic events. These transient pulses of Gas and heat from the deeper magmatic system generate both phreatic eruptions and the observed short-term changes in Gas composition, because at high Gas flux scrubbing of sulfur by the hydrothermal system is both kinetically and thermodynamically inhibited whereas CO2 Gas is always essentially inert in hyperacid conditions. Thus, the SO2/CO2 of lake emissions approaches magmatic values as Gas and power supply to the sub-limnic hydrothermal system increase, vaporizing fluids and priming the hydrothermal system for eruption. Our results suggest that high-frequency real-time Gas monitoring could provide useful short-term eruptive precursors at volcanoes prone to phreatic explosions.
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Gas measurements from the costa rica nicaragua Volcanic segment suggest possible along arc variations in Volcanic Gas chemistry
Earth and Planetary Science Letters, 2014Co-Authors: Bo Galle, Giancarlo Tamburello, Alessandro Aiuppa, Philippe Robidoux, Vladimir Conde, Geoffroy Avard, E Bagnato, J M De Moor, Michael E MartinezAbstract:Obtaining accurate estimates of the CO2 output from arc volcanism requires a precise understanding of the potential along-arc variations in Volcanic Gas chemistry, and ultimately of the magmatic Gas signature of each individual arc segment. In an attempt to more fully constrain the magmatic Gas signature of the Central America Volcanic Arc (CAVA), we present here the results of a Volcanic Gas survey performed during March and April 2013 at five deGassing volcanoes within the Costa Rica-Nicaragua Volcanic segment (CNVS). Observations of the Volcanic Gas plume made with a multicomponent Gas analyzer system (Multi-Gas) have allowed characterization of the CO2/SO2-ratio signature of the plumes at Pads (0.30 +/- 0.06, mean +/- SD), Rincon de la Vieja (27.0 +/- 15.3), and Turrialba (2.2 +/- 0.8) in Costa Rica, and at Telica (3.0 +/- 0.9) and San Cristobal (4.2 +/- 1.3) in Nicaragua (all ratios on molar basis). By scaling these plume compositions to simultaneously measured SO2 fluxes, we estimate that the CO2 outputs at CNVS volcanoes range from low (25.5 +/- 11.0 tons/day at Pods) to moderate (918 to 1270 tons/day at Turrialba). These results add a new information to the still fragmentary Volcanic CO2 output data set, and allow estimating the total CO2 output from the CNVS at 2835 1364 tons/day. Our novel results, with previously available information about Gas emissions in Central America, are suggestive of distinct Volcanic Gas CO2/S-T (= SO2 + H2S)-ratio signature for magmatic volatiles in Nicaragua (similar to 3) relative to Costa Rica (similar to 0.5-1.0). We also provide additional evidence for the earlier theory relating the CO2-richer signature of Nicaragua volcanism to increased contributions from slab-derived fluids, relative to more-MORB-like volcanism in Costa Rica. The sizeable along-arc variations in magmatic Gas chemistry that the present study has suggested indicate that additional Gas observations are urgently needed to more-precisely confine the Volcanic CO2 from the CAVA, and from global arc volcanism.
Nicole Bobrowski - One of the best experts on this subject based on the ideXlab platform.
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a multi purpose multi rotor drone system for long range and high altitude Volcanic Gas plume measurements
Atmospheric Measurement Techniques, 2021Co-Authors: Bo Galle, Nicole Bobrowski, Thorsten Hoffmann, Santiago Arellano, Vladimir Conde, Tobias Fischer, Gustav Gerdes, Alexandra Gutmann, Ima ItikaraiAbstract:Abstract. A multi-rotor drone has been adapted for studies of Volcanic Gas plumes. This adaptation includes improved capacity for high-altitude and long-range, real-time SO2 concentration monitoring, long-range manual control, remotely activated bag sampling and plume speed measurement capability. The drone is capable of acting as a stable platform for various instrument configurations, including multi-component Gas analysis system (MultiGas) instruments for in situ measurements of SO2 , H2S , and CO2 concentrations in the Gas plume and portable differential optical absorption spectrometer (MobileDOAS) instruments for spectroscopic measurement of total SO2 emission rate, remotely controlled Gas sampling in bags and sampling with Gas denuders for posterior analysis on the ground of isotopic composition and halogens. The platform we present was field-tested during three campaigns in Papua New Guinea: in 2016 at Tavurvur, Bagana and Ulawun volcanoes, in 2018 at Tavurvur and Langila volcanoes and in 2019 at Tavurvur and Manam volcanoes, as well as in Mt. Etna in Italy in 2017. This paper describes the drone platform and the multiple payloads, the various measurement strategies and an algorithm to correct for different response times of MultiGas sensors. Specifically, we emphasize the need for an adaptive flight path, together with live data transmission of a plume tracer (such as SO2 concentration) to the ground station, to ensure optimal plume interception when operating beyond the visual line of sight. We present results from a comprehensive plume characterization obtained during a field deployment at Manam volcano in May 2019. The Papua New Guinea region, and particularly Manam volcano, has not been extensively studied for Volcanic Gases due to its remote location, inaccessible summit region and high level of Volcanic activity. We demonstrate that the combination of a multi-rotor drone with modular payloads is a versatile solution to obtain the flux and composition of Volcanic plumes, even for the case of a highly active volcano with a high-altitude plume such as Manam. Drone-based measurements offer a valuable solution to volcano research and monitoring applications and provide an alternative and complementary method to ground-based and direct sampling of Volcanic Gases.
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aerial strategies advance Volcanic Gas measurements at inaccessible strongly deGassing volcanoes
Science Advances, 2020Co-Authors: Nicole Bobrowski, Santiago Arellano, Alessandro Aiuppa, Emma J Liu, A Alan, Marcello Bitetto, S A Carn, Robert ClarkeAbstract:Volcanic emissions are a critical pathway in Earth’s carbon cycle. Here, we show that aerial measurements of Volcanic Gases using unoccupied aerial systems (UAS) transform our ability to measure and monitor plumes remotely and to constrain global volatile fluxes from volcanoes. Combining multi-scale measurements from ground-based remote sensing, long-range aerial sampling, and satellites, we present comprehensive Gas fluxes—3760 ± [600, 310] tons day−1 CO2 and 5150 ± [730, 340] tons day−1 SO2—for a strong yet previously uncharacterized Volcanic emitter: Manam, Papua New Guinea. The CO2/ST ratio of 1.07 ± 0.06 suggests a modest slab sediment contribution to the sub-arc mantle. We find that aerial strategies reduce uncertainties associated with ground-based remote sensing of SO2 flux and enable near–real-time measurements of plume chemistry and carbon isotope composition. Our data emphasize the need to account for time averaging of temporal variability in Volcanic Gas emissions in global flux estimates.
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multicopter measurements of Volcanic Gas emissions at masaya nicaragua turrialba costa rica and stromboli italy volcanoes applications for volcano monitoring and insights into halogen speciation
Atmospheric Measurement Techniques Discussions, 2017Co-Authors: Julian Rudiger, Nicole Bobrowski, Marco Liuzzo, Alexandra Gutmann, Lukas Tirpitz, Maarten J De Moor, M. IbarraAbstract:Volcanoes are a natural source of several reactive Gases (e.g. sulfur and halogen containing species), as well as non-reactive Gases (e.g. carbon dioxide). Besides that, halogen chemistry in Volcanic plumes might have important impacts on atmospheric chemistry, carbon to sulfur ratios and sulfur dioxide fluxes are important established parameters to gain information on subsurface processes. In this study we demonstrate the successful deployment of a multirotor UAV (quadcopter) system with custom-made lightweight payloads on board for the compositional analysis and Gas flux estimation of Volcanic plumes. The various applications and their potential with such new measurement strategy are presented and discussed on example studies at three volcanoes encompassing flight heights of 450 m to 3300 m and various states of Volcanic activity. Field applications were performed at Stromboli Volcano (Italy), Turrialba Volcano (Costa Rica) and Masaya Volcano (Nicaragua). Two in-situ Gas-measuring systems adapted for autonomous airborne measurements, based on electrochemical and optical detection principles, as well as an airborne sampling unit, are introduced. We show Volcanic Gas composition results including, abundances of CO 2 , SO 2 and halogen species. The new instrumental set-ups were compared with established instruments during ground-based measurements. For total SO 2 flux estimations a small differential optical absorption spectroscopy (DOAS) system measured SO 2 column amounts on transversal flights below the plume, showing the potential to replace ground-based manned operations. At Stromboli volcano, short-term fluctuation of the CO 2 / SO 2 ratios could be determined and confirm an increased CO 2 / SO 2 ratio in spatial and temporal proximity to explosions by airborne in-situ measurements. Reactive bromine to sulfur ratios of 0.19 × 10 −4 to 9.8 × 10 −4 were measured in-situ in the plume of Stromboli volcano downwind of the vent.
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periodicity in the bro so 2 molar ratios in the Volcanic Gas plume of cotopaxi and its correlation with the earth tides during the eruption in 2015
Solid Earth, 2017Co-Authors: Nicole Bobrowski, Florian Dinger, Simon Warnach, Stefan Bredemeyer, Silvana Hidalgo, Santiago Arellano, Bo GalleAbstract:Abstract. We evaluated NOVAC (Network for Observation of Volcanic and Atmospheric Change) Gas emission data from the 2015 eruption of the Cotopaxi volcano (Ecuador) for BrO∕SO2 molar ratios. The BrO∕SO2 molar ratios were very small prior to the phreatomagmatic explosions in August 2015, significantly higher after the explosions, and continuously increasing until the end of the unrest period in December 2015. These observations together with similar findings in previous studies at other volcanoes (Mt. Etna, Nevado del Ruiz, Tungurahua) suggest a possible link between a drop in BrO∕SO2 and a future explosion. In addition, the observed relatively high BrO∕SO2 molar ratios after December 2015 imply that bromine deGassed predominately after sulfur from the magmatic melt. Furthermore, statistical analysis of the data revealed a conspicuous periodic pattern with a periodicity of about 2 weeks in a 3-month time series. While the time series is too short to rule out a chance recurrence of transient geological or meteorological events as a possible origin for the periodic signal, we nevertheless took this observation as a motivation to examine the influence of natural forcings with periodicities of around 2 weeks on Volcanic Gas emissions. One strong aspirant with such a periodicity are the Earth tides, which are thus central in this study. We present the BrO∕SO2 data, analyse the reliability of the periodic signal, discuss a possible meteorological or eruption-induced origin of this signal, and compare the signal with the theoretical ground surface displacement pattern caused by the Earth tides. Our central result is the observation of a significant correlation between the BrO∕SO2 molar ratios with the north–south and vertical components of the calculated tide-induced surface displacement with correlation coefficients of 47 and 36 %, respectively. From all other investigated parameters, only the correlation between the BrO∕SO2 molar ratios and the relative humidity in the local atmosphere resulted in a comparable correlation coefficient of about 33 %.
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development and application of a sampling method for the determination of reactive halogen species in Volcanic Gas emissions
Analytical and Bioanalytical Chemistry, 2017Co-Authors: Julian Rudiger, Nicole Bobrowski, Marcello Liotta, Thorsten HoffmannAbstract:Volcanoes release large amounts of reactive trace Gases including sulfur and halogen-containing species into the atmosphere. The knowledge of halogen chemistry in Volcanic plumes can deliver information about subsurface processes and is relevant for the understanding of the impact of volcanoes on atmospheric chemistry. In this study, a Gas diffusion denuder sampling method using 1,3,5-trimethoxybenzene (1,3,5-TMB)-coated glass tubes for the in situ derivatization of reactive halogen species (RHS) was characterized by a series of laboratory experiments. The coating proved to be applicable to collect selectively Gaseous bromine species with oxidation states (OS) of +1 or 0 (such as Br2, BrCl, HOBr, BrO, and BrONO2) while being unreactive to HBr (OS −1). The reaction of 1,3,5-TMB with reactive bromine species forms 1-bromo-2,4,6-TMB—other halogens give corresponding derivatives. Solvent elution of the derivatives followed by analysis with GC-MS results in absolute detection limits of a few nanograms for Br2, Cl2, and I2. In 2015, the technique was applied on Volcanic Gas plumes at Mt. Etna (Italy) measuring reactive bromine mixing ratios between 0.8 and 7.0 ppbv. Total bromine mixing ratios between 4.7 and 27.5 ppbv were derived from alkaline trap samples, simultaneously taken by a Raschig tube and analyzed with IC and ICP-MS. This leads to the first results of the reactive bromine contribution to total bromine in Volcanic emissions, spanning over a range between 12% (±1) and 36% (±2). Our finding is in an agreement with previous model studies, which imply values <44% for plume ages <1 min, which is consistent with the assumed plume age at the sampling sites.
Ryunosuke Kazahaya - One of the best experts on this subject based on the ideXlab platform.
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variation of Volcanic Gas composition at a poorly accessible volcano sakurajima japan
Journal of Volcanology and Geothermal Research, 2020Co-Authors: Hiroshi Shinohara, Ryunosuke Kazahaya, Takao Ohminato, Takayuki Kaneko, Urumu Tsunogai, M MoritaAbstract:Abstract Volcanic Gas compositions are estimated based on Volcanic plume measurement with Multi-Gas at a frequently erupting Sakurajima volcano by application of airborne methods and automatic monitoring station on the flank during 2013–2019. The airborne measurements of CO2 and H2O concentrations often suffer from large fluctuation of background likely due to entrainment of the atmosphere derived from different altitude. By removing the background effect, a representative Volcanic CO2/SO2 mole ratio is estimated as 0.4 ± 0.1 and we did not observe clear temporal variation. The Volcanic H2O/SO2 ratios are estimated as 30–70 with a large uncertainty because of the strong atmospheric perturbation. The SO2/H2S ratios show quite a large variation ranging from 1 to 800. The large SO2/H2S ratios larger than 30 are observed during ash eruption and are suggested as a result of oxidation by atmosphere on hot ashes. The small ratios less than 10 are observed when frequency of explosions is low. Variation of the SO2/H2S ratios of the small values can be caused by variation of deGassing pressure, however, the small variation of the CO2/SO2 ratio suggests a limited range of the pressure variation.
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Airborne measurements of Volcanic Gas composition during unrest at Kuchinoerabujima volcano, Japan
Bulletin of Volcanology, 2019Co-Authors: Ryunosuke Kazahaya, Hiroshi Shinohara, Takao Ohminato, Takayuki KanekoAbstract:Airborne measurements of Volcanic Gas composition using an unmanned aerial vehicle (UAV) and Cessna aircraft were conducted at Kuchinoerabujima volcano, Japan, between 2014 and 2016. Because eruptions occurred in August 2014, May 2015, and June 2015, access to the summit crater was limited because of the risk of sudden eruption such that airborne measurements were the only viable method to measure the Volcanic Gas composition. Multi-Gas and alkali-filter pack measurements were made on the leeward side of the crater and around the crater, using the Cessna and UAV, respectively. Observations using the UAV could measure the dense plume and quantify the Gas species of H2O, CO2, SO2, H2S, H2, HCl, and HF, while the observations using the Cessna could measure only the diluted plume and quantify CO2, SO2, H2S, and H2. The seven airborne observations enabled us to monitor variations in the Volcanic Gas composition. Over the observation period, the SO2/H2S ratio decreased from 10 to 1.9. The H2O/SO2 ratio, H2/SO2 ratio, and apparent equilibrium temperatures (AET) estimated using the Volcanic Gas composition increased after the 2014 eruption. The decrease in the SO2/H2S ratio might be attributed to changes in the pressure of deGassing magma and interactions with the hydrothermal system. The airborne methods presented here highlight the utility of using light aircrafts to safely conduct Volcanic Gas measurements during periods of Volcanic unrest when traditional ground-based methods are not possible.
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variation of Volcanic Gas composition during the eruptive period in 2014 2015 at nakadake crater aso volcano japan
Earth Planets and Space, 2018Co-Authors: Hiroshi Shinohara, Akihiko Yokoo, Ryunosuke KazahayaAbstract:Volcanic Gas composition measurement by Multi-Gas was repeated during the eruptive period in 2014–2015 as well as the quiet period preceding the eruption at Nakadake crater, Aso volcano. The eruptive activity is characterized by continuous ash emission with intermittent Strombolian activity and temporal pauses. Volcanic Gas composition measured during the eruptive period showed a rapid and large variation. In particular, the CO2/SO2 and SO2/H2S ratios varied in the rages of 1–8 and 3–300 during the ash eruption with a clear negative correlation. The large variation and the negative correlation of the compositions are attributed to two orders of magnitude difference of deGassing pressure, such as 20 and 0.2 MPa; the Gases with the large CO2/SO2 and the small SO2/H2S ratios are derived from the high pressure. The rapid and large composition variation suggests frequent ascent of bubbles formed at various depth during the eruption. The maximum CO2/SO2 ratio decreased with decreasing eruption intensity that suggests decrease in contribution of the bubbles derived from a large depth. With time, H2O/SO2 ratio of the Gases increases from 30 to > 60, suggesting increase in a hydrothermal contribution.
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monitoring of Volcanic Gas composition at asama volcano japan during 2004 2014
Journal of Volcanology and Geothermal Research, 2015Co-Authors: Hiroshi Shinohara, Takao Ohminato, Minoru Takeo, Hiroshi Tsuji, Ryunosuke KazahayaAbstract:Abstract The composition of the Volcanic Gases discharged from the summit crater of Asama volcano has been monitored since 2004 by Multi-Gas and alkaline-filter techniques. The persistent deGassing activity at Asama volcano is characterized by large variation of SO 2 flux. The CO 2 /SO 2 and H 2 O/SO 2 ratios did not show clear variation irrespective of the SO 2 flux variation and a few eruptions that occurred during active deGassing periods. The estimated ratios have large uncertainty due to variable contribution of the different fumaroles in the summit crater to the Volcanic plume and lack of a systematic variation can be due to the large uncertainty. The SO 2 /Cl ratio showed a systematic decrease after the eruption to the inactive period, suggesting that deGassing pressure did not significantly increase after the eruption. Low-pressure deGassing along with the continuous and intensive Gas discharge suggests that the deGassing is due to conduit magma convection. The apparently stable CO 2 /SO 2 ratios imply a lack of significant volatile differentiation in the magma reservoir, such as CO 2 -rich bubble accumulation. The large variation of the SO 2 flux along with stable Gas composition implies that the large changes in magma convection rate are caused by changes in the radius of the convecting magma conduit.
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budget of shallow magma plumbing system at asama volcano japan revealed by ground deformation and Volcanic Gas studies
Journal of Geophysical Research, 2015Co-Authors: Ryunosuke Kazahaya, Yosuke Aoki, Hiroshi ShinoharaAbstract:Multiple cycles of the intensive Volcanic Gas discharge and ground deformation (inflation and deflation) were observed at Asama Volcano, Japan, from 2000 to 2011. Magma budget of the shallow magma plumbing system was estimated on the basis of the Volcanic Gas emission rates and ground deformation data. Recent inflations observed in 2004 and 2008 were modeled as a dike intrusion to 2–3 km west of Asama Volcano. Previous studies proposed that magma ascends from a midcrustal magma reservoir to the dike and reaches the surface via a sinuous conduit which connects the dike to the summit. The intensive Volcanic sulfur dioxide discharge of up to 4600 t/d at the volcano was modeled by magma convective deGassing through this magma pathway. The volcano deflates as shrinkage of the magma in a reservoir by Volcanic Gas discharge. We estimated the volume change of the dike modeled based on the GPS observations, the volume decrease of the magma by the Volcanic Gas discharge, and the amount of deGassed magma produced to calculate the magma budget. The results show that the volume decrease of the magma by the Volcanic Gas discharge was larger than the volume change of the dike during the inflation periods. This indicates that a significant volume of magma at least more than 2 times larger than the volume change of the dike was supplied from the midcrustal magma reservoir to the dike. The volume decrease of the dike was comparable with the volume decrease of the magma by the Volcanic Gas discharge during the deflation periods. The long-term deflation trend of the dike and the volume of deGassed magma (108–9 m3) suggest that the deGassed magma produced is not stored in the dike and the magma is mainly supplied from the midcrustal magma reservoir. In both periods, the volume of deGassed magma produced was 1 order of magnitude larger than the volume change of the dike. This indicates that the actual volume of the magma supplied from the midcrustal magma reservoir is up to 1 order of magnitude larger than the volume change of the dike. These results strongly suggest that an amount of magma moved through a magma reservoir is possible to be significantly larger than volume change of the magma reservoir estimated by the geodetic observations.
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a multi purpose multi rotor drone system for long range and high altitude Volcanic Gas plume measurements
Atmospheric Measurement Techniques, 2021Co-Authors: Bo Galle, Nicole Bobrowski, Thorsten Hoffmann, Santiago Arellano, Vladimir Conde, Tobias Fischer, Gustav Gerdes, Alexandra Gutmann, Ima ItikaraiAbstract:Abstract. A multi-rotor drone has been adapted for studies of Volcanic Gas plumes. This adaptation includes improved capacity for high-altitude and long-range, real-time SO2 concentration monitoring, long-range manual control, remotely activated bag sampling and plume speed measurement capability. The drone is capable of acting as a stable platform for various instrument configurations, including multi-component Gas analysis system (MultiGas) instruments for in situ measurements of SO2 , H2S , and CO2 concentrations in the Gas plume and portable differential optical absorption spectrometer (MobileDOAS) instruments for spectroscopic measurement of total SO2 emission rate, remotely controlled Gas sampling in bags and sampling with Gas denuders for posterior analysis on the ground of isotopic composition and halogens. The platform we present was field-tested during three campaigns in Papua New Guinea: in 2016 at Tavurvur, Bagana and Ulawun volcanoes, in 2018 at Tavurvur and Langila volcanoes and in 2019 at Tavurvur and Manam volcanoes, as well as in Mt. Etna in Italy in 2017. This paper describes the drone platform and the multiple payloads, the various measurement strategies and an algorithm to correct for different response times of MultiGas sensors. Specifically, we emphasize the need for an adaptive flight path, together with live data transmission of a plume tracer (such as SO2 concentration) to the ground station, to ensure optimal plume interception when operating beyond the visual line of sight. We present results from a comprehensive plume characterization obtained during a field deployment at Manam volcano in May 2019. The Papua New Guinea region, and particularly Manam volcano, has not been extensively studied for Volcanic Gases due to its remote location, inaccessible summit region and high level of Volcanic activity. We demonstrate that the combination of a multi-rotor drone with modular payloads is a versatile solution to obtain the flux and composition of Volcanic plumes, even for the case of a highly active volcano with a high-altitude plume such as Manam. Drone-based measurements offer a valuable solution to volcano research and monitoring applications and provide an alternative and complementary method to ground-based and direct sampling of Volcanic Gases.
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periodicity in the bro so 2 molar ratios in the Volcanic Gas plume of cotopaxi and its correlation with the earth tides during the eruption in 2015
Solid Earth, 2017Co-Authors: Nicole Bobrowski, Florian Dinger, Simon Warnach, Stefan Bredemeyer, Silvana Hidalgo, Santiago Arellano, Bo GalleAbstract:Abstract. We evaluated NOVAC (Network for Observation of Volcanic and Atmospheric Change) Gas emission data from the 2015 eruption of the Cotopaxi volcano (Ecuador) for BrO∕SO2 molar ratios. The BrO∕SO2 molar ratios were very small prior to the phreatomagmatic explosions in August 2015, significantly higher after the explosions, and continuously increasing until the end of the unrest period in December 2015. These observations together with similar findings in previous studies at other volcanoes (Mt. Etna, Nevado del Ruiz, Tungurahua) suggest a possible link between a drop in BrO∕SO2 and a future explosion. In addition, the observed relatively high BrO∕SO2 molar ratios after December 2015 imply that bromine deGassed predominately after sulfur from the magmatic melt. Furthermore, statistical analysis of the data revealed a conspicuous periodic pattern with a periodicity of about 2 weeks in a 3-month time series. While the time series is too short to rule out a chance recurrence of transient geological or meteorological events as a possible origin for the periodic signal, we nevertheless took this observation as a motivation to examine the influence of natural forcings with periodicities of around 2 weeks on Volcanic Gas emissions. One strong aspirant with such a periodicity are the Earth tides, which are thus central in this study. We present the BrO∕SO2 data, analyse the reliability of the periodic signal, discuss a possible meteorological or eruption-induced origin of this signal, and compare the signal with the theoretical ground surface displacement pattern caused by the Earth tides. Our central result is the observation of a significant correlation between the BrO∕SO2 molar ratios with the north–south and vertical components of the calculated tide-induced surface displacement with correlation coefficients of 47 and 36 %, respectively. From all other investigated parameters, only the correlation between the BrO∕SO2 molar ratios and the relative humidity in the local atmosphere resulted in a comparable correlation coefficient of about 33 %.
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Gas measurements from the costa rica nicaragua Volcanic segment suggest possible along arc variations in Volcanic Gas chemistry
Earth and Planetary Science Letters, 2014Co-Authors: Bo Galle, Giancarlo Tamburello, Alessandro Aiuppa, Philippe Robidoux, Vladimir Conde, Geoffroy Avard, E Bagnato, J M De Moor, Michael E MartinezAbstract:Obtaining accurate estimates of the CO2 output from arc volcanism requires a precise understanding of the potential along-arc variations in Volcanic Gas chemistry, and ultimately of the magmatic Gas signature of each individual arc segment. In an attempt to more fully constrain the magmatic Gas signature of the Central America Volcanic Arc (CAVA), we present here the results of a Volcanic Gas survey performed during March and April 2013 at five deGassing volcanoes within the Costa Rica-Nicaragua Volcanic segment (CNVS). Observations of the Volcanic Gas plume made with a multicomponent Gas analyzer system (Multi-Gas) have allowed characterization of the CO2/SO2-ratio signature of the plumes at Pads (0.30 +/- 0.06, mean +/- SD), Rincon de la Vieja (27.0 +/- 15.3), and Turrialba (2.2 +/- 0.8) in Costa Rica, and at Telica (3.0 +/- 0.9) and San Cristobal (4.2 +/- 1.3) in Nicaragua (all ratios on molar basis). By scaling these plume compositions to simultaneously measured SO2 fluxes, we estimate that the CO2 outputs at CNVS volcanoes range from low (25.5 +/- 11.0 tons/day at Pods) to moderate (918 to 1270 tons/day at Turrialba). These results add a new information to the still fragmentary Volcanic CO2 output data set, and allow estimating the total CO2 output from the CNVS at 2835 1364 tons/day. Our novel results, with previously available information about Gas emissions in Central America, are suggestive of distinct Volcanic Gas CO2/S-T (= SO2 + H2S)-ratio signature for magmatic volatiles in Nicaragua (similar to 3) relative to Costa Rica (similar to 0.5-1.0). We also provide additional evidence for the earlier theory relating the CO2-richer signature of Nicaragua volcanism to increased contributions from slab-derived fluids, relative to more-MORB-like volcanism in Costa Rica. The sizeable along-arc variations in magmatic Gas chemistry that the present study has suggested indicate that additional Gas observations are urgently needed to more-precisely confine the Volcanic CO2 from the CAVA, and from global arc volcanism.
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network for observation of Volcanic and atmospheric change novac a global network for Volcanic Gas monitoring network layout and instrument description
Journal of Geophysical Research, 2010Co-Authors: Bo Galle, Santiago Arellano, Christoph Kern, U Platt, Mattias Erik Johansson, Yan Zhang, Claudia Rivera, Manne Kihlman, Thomas LehmannAbstract:This paper presents the global project Network for Observation of Volcanic and Atmospheric Change (NOVAC), the aim of which is automatic Gas emission monitoring at active volcanoes worldwide. Data from the network will be used primarily for Volcanic risk assessment but also for geophysical research, studies of atmospheric change, and ground validation of satellite instruments. A novel type of instrument, the scanning miniaturized differential optical absorption spectroscopy (Mini-DOAS) instrument, is applied in the network to measure Volcanic Gas emissions by UV absorption spectroscopy. The instrument is set up 5-10 km downwind of the volcano under study, and typically two to four instruments are deployed at each volcano in order to cover different wind directions and to facilitate measurements of plume height and plume direction. Two different versions of the instrument have been developed. Version I was designed to be a robust and simple instrument for measurement of Volcanic SO2 emissions at high time resolution with minimal power consumption. Version II was designed to allow the best possible spectroscopy and enhanced flexibility in regard to measurement geometry at the cost of larger complexity, power consumption, and price. In this paper the project is described, as well as the developed software, the hardware of the two instrument versions, measurement strategies, data communication, and archiving routines. As of April 2009 a total of 46 instruments have been installed at 18 volcanoes worldwide. As a typical example, the installation at Tungurahua volcano in Ecuador is described, together with some results from the first 21 months of operation at this volcano.
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the dual beam mini doas technique measurements of Volcanic Gas emission plume height and plume speed with a single instrument
Bulletin of Volcanology, 2009Co-Authors: Mattias Erik Johansson, Bo Galle, Yan Zhang, Claudia Rivera, Deliang Chen, Klaus WyserAbstract:The largest error in determining Volcanic Gas fluxes using ground based optical remote sensing instruments is typically the determination of the plume speed, and in the case of fixed scanning instruments also the plume height. We here present a newly developed technique capable of measuring plume height, plume speed and Gas flux using one single instrument by simultaneously collecting scattered sunlight in two directions. The angle between the two measurement directions is fixed, removing the need for time consuming in-field calibrations. The plume height and Gas flux is measured by traversing the plume and the plume speed is measured by performing a stationary measurement underneath the plume. The instrument was tested in a field campaign in May 2005 at Mt. Etna, Italy, where the measured results are compared to wind fields derived from a meso-scale meteorological model (MM5). The test and comparison show that the instrument is functioning and capable of estimating wind speed at the plume height.
