IAVCEI 2013 Scientific Assembly - July 20 - 24, Kagoshima, Japan
Forecasting Volcanic Activity - Reading and translating the messages of nature for society

3A1_2G-O1

Room B2

Date/Time: July 23 8:45-9:00

Experimental constraints on deep CO2 -rich fluid degassing at arc volcanoes
Margaret Mangan1 , Thomas Sisson1 , William Hankins1 , Nobumichi Shimizu2 , Torsten Vennemann3
1

US Geological Survey, US, 2 Woods Hole Oceanographic Institution, US, 3 University of Lausanne, CH
E-mail: mmangan@usgs.gov

Several petrologic and geophysical studies suggest that basaltic magmas residing deep in the roots of many
volcanic systems are saturated with an exsolved, CO2 -rich vapor. These CO2 -rich fluids help to form magma
pathways by penetrating and pressurizing tensile micro-cracks at the tips of propagating dikes and sills in advanceof rising magma.

To estimate the pressure (depth) of deep CO2 -rich degassing under arc volcanoes, solubility experiments
on basaltic andesite with 2-6 wt% H2 O and 1 wt% CO2 (from Ag oxalate) were conducted using a piston cylinder
apparatus at 1125°C and pressures of 400-1200 MPa. A welded inner AuPd capsule containing hydrated rockpowder and Ag oxalate was placed in an outer Pt capsule in which Ni-NiO buffer and oxalic acid plus Ag oxalate
were added. Proportions of oxalic acid to Ag oxalate were set to mimic the anticipated composition of the excess
fluid in equilibrium with the melt to reduce the diffusion of hydrogen through the inner capsule (mol fractions CO2
of 0.70-0.95).

Concentrations of dissolved CO2 and H2 O in the quenched glasses were determined by manometry at the
University of Lausanne and by ion microprobe at the Northeast National Ion Microprobe Facility. The experimental
uncertainties are ≤ 10% for CO2 and ≤ 7% for H2 O. In contrast to published experiments at lower pressure(<400 MPa), no systematic dependence of CO2 on H2 O was noted in glasses over dissolved water concentrations
between 2.3-5.3 wt%. Instead, the data demonstrate the over-riding influence of pressure on CO2 solubility in
deep-crustal, moderately-hydrated basaltic magma. A power law decrease in dissolved CO2 with decreasingpressure given by CO2 (± 480 ppm) = 0.0008(P(MPa))2.36 with r2 = 0.95 best describes the relation. This result
is consistent with the numerical model of Papale et al. (Chem. Geol. 2006) which predicts flattening of the
H2 O-CO2 isobaric saturation surface for basaltic magma containing ∼2-6 wt% H2 O at pressures above 400 MPa.
However, the absolute concentrations of dissolved CO2 in the quenched glasses suggest that the Papale et al.
model under-estimates pressures of fluid saturation by ∼20%. Solubility data from mixed H2 O-CO2 experiments of
Shishkina et al. (Chem. Geol. 2008) show similar results for tholeiitic basalt at 500 MPa and H2 O ≤ 4.0 wt%.

In broad terms, the results of these experiments imply that 80-90% of the CO2 initially dissolved in basaltic
magma below arc volcanoes can be released by decompression exsolution at levels deeper than ∼20 km.

©IAVCEI 2013 Scientific Assembly. All rights reserved.

534

IAVCEI 2013 Scientific Assembly - July 20 - 24, Kagoshima, Japan
Forecasting Volcanic Activity - Reading and translating the messages of nature for society

3A1_2G-O2

Room B2

Date/Time: July 23 9:00-9:15

CO2 , SO2 , and H2 S degassing related to the 2009 Redoubt eruption, Alaska
Cynthia Werner1 , Peter J Kelly2 , William C Evans3 , Micheal P Doukas2 , Robert McGimsey1 , Christina
Neal1
1

US Geolgical Survey, Alaska Volcano Observatory, USA, 2 US Geolgical Survey, Cascades Volcano
Observatory, USA, 3 US Geolgical Survey, Menlo Park, USA
E-mail: cwerner@usgs.gov

Emissions of CO2 , SO2 , and H2 S from the 2009 eruption of Redoubt Volcano, Alaska were well monitored. Elevated
CO2 emissions were measured 5 months prior to the eruption and varied from 3630 to 9020 tonnes per day (t/d) in
the 6 weeks prior to the eruption. In contrast, low S emissions were typical during the pre–eruptive period, resulting
in molar C/S ratios of 30–60. However, the high C/S ratio dropped to a value typical for Cook Inlet volcanoes (ave.
= 2.4) coincident with the first phreatic explosion on March 15, 2009, and remained low throughout all phases ofthe eruption. Observations of melt water discharge and water chemistry leading up to the eruption suggested that
surface waters represented drainage from surficial lenses of condensed magmatic steam and glacial meltwater, andthat only a few hundred tonnes/day of SO2 were reacting to a dissolved component, not the > 2100 t/d SO2 expectedfrom degassing of magma in the upper crust (3–6.5 km), where petrologic analysis showed that the final magma
equilibration occurred. Thus, the high pre-eruptive C/S ratios could reflect bulk degassing of upper–crustal magma
followed by nearly complete loss of SO2 in a magmatic–hydrothermal system deep in the edifice, though no clearhydrothermal component was detected in the analyses of the effluent, even in post–eruption sampling (Oct. 2012).
Alternatively, we prefer that the high C/S ratios are attributed to degassing of low silica andesitic (LSA) magma that
intruded the mid–crust in the 5 months prior to eruption; modeling suggests that mixing of this LSA magma witha pre–existing high silica andesite magma or mush in the mid–to–upper crust would have resulted in a C/S ratio
consistent with that measured during the eruption. Maximum emission rates measured with airborne techniques
were 33,110 t/d CO2 , 16,650 t/d SO2 , and 1230 t/d H2 S. Pre–eruptive open system degassing accounted for 14%of the total CO2 and 4% of total SO2 , whereas post–eruptive degassing was responsible for 27 and 30% of the total
CO2 and SO2 with measurements extending over one year following the cessation of dome extrusion. The magma
degassed primarily as a closed system with approximately 59 and 66% of the total CO2 and SO2 , respectively,
emitted during the explosive and dome growth periods. SO2 made up on average 92% of the total S throughout theeruption. Primary volatile contents calculated from pairing degassing estimates with the erupted magma volumes
over the same time periods range from 0.9–2.1 wt.% CO2 and 0.27–0.56 wt.% S, with preferred estimates of 1.25
wt.% CO2 and 0.35 wt.% S. Assuming these values, up to 30% more magma degassed in the year following final
dome emplacement.

©IAVCEI 2013 Scientific Assembly. All rights reserved.

535

IAVCEI 2013 Scientific Assembly - July 20 - 24, Kagoshima, Japan
Forecasting Volcanic Activity - Reading and translating the messages of nature for society

3A1_2G-O3

Room B2

Date/Time: July 23 9:15-9:30

Magmatic gases of Gorely volcano, Kamchatka: element fluxes and comparison with
MultiGas data
Yuri Taran1 , Ilya Chaplygin2
1

Institute of Geophysics, Universidad Nacional Autonoma de Mexico, Mexico, 2 Institute of Ore Deposits,
Russian Academy of Sciences, Russia
E-mail: yuri.taran@gmail.com

Basaltic Gorely volcano at Southern Kamchatka is characterized by a strong gas emission from its active crater
since 1980. The volcano is located within a large caldera, 15 km to the NW from another strong gas emitter,
Mutnovsky volcano. Remote measurements in September 2011 revealed the SO2 flux from Gorely in the rangeof 400 to 1100 t/day (800 t/day on average). The MultiGas measurements of the plume composition on the craterrim realized at the same time showed that the gas is water and chlorine rich, with C/S ∼1 and S/Cl ∼ 2 (Aiuppa etal., 2012). Direct sampling of the 850 °C fumarole near the crater floor and the cold acidic crater lake was done
two weeks after the DOAS and MultiGas measurements. Isotopic composition of magmatic vapor corresponds
to mixing 25% of meteoric water with typical "andesitic water". Trace element composition of the volcanic gas
condensates are compared with the available data from other high temperature volcanic gas emissions, inparticular, with the chemistry of fumarolic condensates of Kudryavy volcano. Condensate of Gorely shows asimilar trace element pattern but with a notable enrichment in chalcophile and depletion in siderophile elements
comparing to Kudryavy. Concentrations of Re (up to 20 ppb) is similar for both volcanoes. Concentrations of Au
and elements of Pt group are lower than detection limit of ICPMS. REE distribution in the Gorely condensate isparallel to the REE rock pattern with a slight enrichment in both light and heavy REE. Results for main components
generally confirm those obtained by the MultiGas technique though there are some differences:

Date of sampling H2O CO2 SO2 HCl C/S S/Cl
Direct20.09.2011

94.9 1.7 1.9 0.83 0.91 2.26

MultiGas 06.09.2011

93.2 2.7 2.3 1.2 1.17 1.92

Emission rates of elements are calculated using their SO2/E ratios and the average SO2 flux from Gorelyof 800 t/day.

Aiuppa, A., et al.

First volatile inventory for Gorely volcano, Kamchatka.

2012.

©IAVCEI 2013 Scientific Assembly. All rights reserved.

536

Geoph.

Res.

Lett., 39, L0637,

IAVCEI 2013 Scientific Assembly - July 20 - 24, Kagoshima, Japan
Forecasting Volcanic Activity - Reading and translating the messages of nature for society

3A1_2G-O4

Room B2

Date/Time: July 23 9:30-9:45

The magmatic-hydrothermal transition: Observations from the 2012 eruptions of White
Island and Tongariro, New Zealand
Bruce W Christenson1 , Arthur Jolly2 , Karen Britten2 , Agnes Mazot2
1

National Isotope Centre, GNS Science, New Zealand, 2 Wairaki Researcch Centre, GNS Science, New
ZealandE-mail: b.christenson@gns.cri.nz

The 4 August 2012 phreatomagmatic eruption of White Island was the first significant activity from this volcano
since February 2001. Although small in size and duration, the eruption was followed by the building of a 20 m hightuff cone, and subsequent extrusion of a small lava dome. Some 6 months prior to the eruption, low temperature(100 °C - 200 °C) fumaroles on the main crater floor began to show increasing trends in CO2 /CH4 , CO2 /H2 O, C/S
and CO/CO2 ratios, constituting shifts from hydrothermal to increasingly magmatic signatures. These changes
were also accompanied by a progressive isotopic shift in δ 15 N2 from +2.9 ‰to +5.5 ‰. This is the heaviest
δ 15 N signature yet encountered in the Taupo Volcanic Zone, and provides new insights into the TVZ magmatic
N2 end-member composition. These anomalies were coupled to an increase in harmonic and broad spectrum
tremor during the same period. Together, these observations provide an unequivocal context for recognising
future eruptive activity, but also criteria for constraining hydrothermal system response, and gas-magma transport
behaviour in this volcano.

Similarly, and just two days after the White Island eruption, the 6 August 2012 phreatic eruption of Te Mari,
Mt Tongariro marked the re-awakening of this volcano which last erupted in 1896. This eruption was accompanied
by precursory volcano-tectonic earthquakes, and by marked changes in chemical signatures of gases emitted fromthe Lower Te Mari fumaroles. Fumarolic gas sampled from the western rim of Lower Te Mari crater on 22 May 2012
showed no significant changes from baseline values. Earthquake activity commenced on 13 July, and intensified
over the period of 18-21 July with approximately 120 located hybrid and volcano-tectonic events. Fumarolic gases
collected on July 21 revealed significant changes in gas signatures from the Lower Te Mari fumaroles by this time,with key ratios of CO2 /CH4 and N2 /Ar increasing from 5,400 to 91,200 and 91 to 1,245 respectively, and increasing
further to 121,000 and 1,300 respectively by 27 July. During this time there were no significant changes in fumarolictemperatures or pressures, suggesting that permeabilities in the hydrothermal system were low, and were throttlinggas transfer from below. Baseline C/S mole ratios for Te Mari fumaroles are close to 5. Immediately prior to theAug 6 eruption, C/S had fallen to ca. 3, and post eruption fell to < 1, consistent with extensive degassing of a small
magma volume. A second, short-lived pulse of CO2 -rich gas was recognised in late September, but this did notlead to further eruption activity. The current model for this activity involves open-system degassing of shallowly
emplaced dike intrusion(s) beneath the volcano.

©IAVCEI 2013 Scientific Assembly. All rights reserved.

537

IAVCEI 2013 Scientific Assembly - July 20 - 24, Kagoshima, Japan
Forecasting Volcanic Activity - Reading and translating the messages of nature for society

3A1_2G-O5

Room B2

Date/Time: July 23 9:45-10:00

Gas emission measurements of the active lava lake of Niyragongo, DR Congo
Nicole Bobrowski1 , Giovanni Giuffrida2 , Dario Tedesco3 , Mathiew Yalire4 , Santiago Arellano5 , Charles
Balagizi4 , Bo Galle5
1Institut fuer Umweltphysik, Universitaet Heidelberg, Germany, 2 Institute Nazionale Geofisica e
Vulcanologia, Palermo, Italy, 3 Universita Napoli, Caserta, Italy, 4 Observatoire Volcanologique de Goma,
D.R. Congo, 5 Chalmers University of Technology, Goeteborg, Sweden
E-mail: nbobrows@iup.uni-heidelberg.de

Between 2007 and 2011 four measurement campaigns (June 2007, July 2010, June 2011 and December 2011)were carried out at the crater rim of Nyiragongo volcano, DR Congo. Nyiragongo is considered one of the mostactive volcanoes in Africa. The ground based remote sensing technique Multi Axis Differential Optical Absorption
spectroscopy (MAXDOAS) using scattered sunlight and a Multigas instrument have been simultaneously applied
during all field trips and among others bromine monoxide/sulphur dioxide (BrO/SO2) and carbon dioxide/sulphur
dioxide (CO2/SO2) ratios were determined. At the various field trips lava lake level changes were observed (in theorder of minutes up to days and also between the years). The measured gas ratios varied as well for CO2/SO2
ratios between 1.2 and 16.2 and between 0.2 and 1.6 x 10-5 for BrO/SO2 ratios. BrO/SO2 ratios showed similar
behavior as CO2/SO2 ratios. Higher CO2/SO2 ratios and BrO/SO2 levels were generally observed at higher lava
lake levels and a decrease of the lava lake was accompanied by a decrease in the BrO/SO2 as well as CO2/SO2
ratio. During all campaign also Cl/S ratios have been determined by filterpack sampling. Overall the Cl/S ratioshows an increase with time from earlier literature data of 0.05 to up to 0.55 in 2011, which is accompanied by adecreasing sulfur dioxide flux.
A model is proposed, which assumes various convective magma cells inside the conduit and the possible temporaryinterruption of part of the cycling. This model is able to explain our data set as a whole.

©IAVCEI 2013 Scientific Assembly. All rights reserved.

538

IAVCEI 2013 Scientific Assembly - July 20 - 24, Kagoshima, Japan
Forecasting Volcanic Activity - Reading and translating the messages of nature for society

3A1_2G-O6

Room B2

Date/Time: July 23 10:00-10:15

First measurement of magma degassing processes and co-varying seismic tremor
during an eruption of Piton de la Fournaise hot spot basaltic volcano, Reunion island
Patrick Allard1 , Alessandro La Spina2 , Giancarlo Tamburello3 , Alessandro Aiuppa3 , Andrea Di Muro4 ,Diego Coppola5 , Jean Battaglia6 , Mike Burton7 , Florent Brenguier4 , Thomas Staudacher4
1

Institut de Physique du Globe de Paris (IPGP), UMR7154 CNRS, Paris, France, 2 Istituto Nazionale diGeofisica e Vulcanologia (INGV), Catania, Italy, 3 DISTEM, Universita di Palermo, Palermo, Italy,
4
Observatoire Volcanologique du Piton de la Fournaise, IPGP, La Reunion, France, 5 Dipartimento di
Scienze Mineralogiche e Petrologiche, Universita di Torino, Italy, 6 LMV, CNRS-Univ. Blaise Pascal,
Clermont-Ferrand, France, 7 Istituto Nazionale di Geofisica e Vulcanologia (INGV), Pisa, Italy
E-mail: pallard@ipgp.fr

Piton de la Fournaise (PdF), in the western Indian Ocean, is a very active hot spot basaltic volcano whose eruptions(1 to 2 per year on average) are well anticipated by the local geophysical monitoring network but whose magmaticgases had never been measured. Here we report on the first data for magmatic gas composition (OPFTIR
absorption spectroscopy, in situ MultiGas analysis plus filterpack sampling) and budget (DOAS), coupled withrecording of seismic tremor and the lava extrusion rate (space-borne MODIS sensing), during a fissure eruptionof PDF in October 2010. Dyke ascent from about 2 km beneath the summit crater was tracked by a few hoursof precursory seismic signals and volcano deformation. After a strong initial burst coinciding with eruptive fissure
opening, both the tremor amplitude, lava extrusion rate and SO2 flux coherently decreased during the first week of
eruption. The emitted magmatic gases, whose composition varied slightly over time, were found to be water-richand to display high S/Cl but low C/S, Cl/F and Cl/Br ratios. These features are consistent with a hydrous hot spot
mantle source and previous volatile fractionation during shallow magma storage. Volatile fluxes referred to themagma extrusion rate and available melt inclusion data point to essentially syn-eruptive (closed system) degassingof sulfur, chlorine and fluorine during the first half of the eruption. In contrast, additional inputs of CO2 and H2O arerequired to explain the gas composition. Differential CO2 bubbling is supported by high-frequency correlations
between the FTIR-sensed CO2/HCl ratio and seismic tremor, while entrainment of hydrothermal steam might
have enhanced the H2O gas content. The second week of the eruption was marked by a spectacular decoupling
between declining lava extrusion and reincreasing seismic tremor amplitude (especially in the low-frequency band),indicating a key control of tremor and degassing activity by differential (open system) gas bubbling across the feeder
dyke. Finally, the end of the eruption was preceded by a new sharp tremor increase, with remarkable anti-correlated
variations of the 1-3 Hz and 3-5 Hz spectral signals, which we attribute to abrupt geometrical changes prior to dyke
closure. Combined geochemical and geophysical survey of Piton de la Fournaise volcano in the future should
permit a better understanding and forecasting of its eruptive behavior.

©IAVCEI 2013 Scientific Assembly. All rights reserved.

539

IAVCEI 2013 Scientific Assembly - July 20 - 24, Kagoshima, Japan
Forecasting Volcanic Activity - Reading and translating the messages of nature for society

3A2_2G-O7

Room B2

Date/Time: July 23 10:45-11:00

Volatile evolution of magma plumbing system of the 2000 eruption at Miyakejima volcano
deduced from melt inclusion analyses
Genji Saito, Yuichi Morishita, Hiroshi Shinohara
Geological Survey of Japan, National Institute of Advance Industrial Science and Technology, Japan
E-mail: saito-g@aist.go.jp

The 2000 eruption of Miyakejima volcano, Japan, is characterized by intrusion of a dyke and a submarine
eruption in June, subsidence of the summit area with phreatic and phreatomagmatic explosions in July to August,and intense and continuous degassing from the summit after the major eruptions (e.g., Nakada et al., 2005).
Geophysical and petrological observations suggested that shallow andesitic and deeper basaltic magma chambers
existed beneath the volcano before the 2000 eruption (e.g., Amma-Miyasaka et al., 2005). In this study, petrologicaland melt inclusion studies were carried out in order to know volatile evolution of the magma plumbing system. We
can consider three component magmas, "A" magma in the shallow magma chamber erupted at the submarine
eruption, and "B" and "C" magmas erupted at the summit eruptions. The C magma represents the deeper-sourced
basaltic magma and the B magma was produced by 40 wt% fractional crystallization of the C magma. The bimodal
olivine core composition and diffusion profiles of the olivines in the ejecta of the summit eruptions indicate the mixingof B and C magmas in two months before the eruption. The melt inclusions in Mg-rich olivines derived from theC magma have slightly higher H2 O (1.9-3.5 wt%) and S (0.06-0.21 wt%) contents, and a lower Cl (0.04-0.07 wt%)
content than the inclusions in Mg-poor olivines from the B magma, while they have similar CO2 (0.003-0.025 wt%)
contents. The wide range of CO2 contents can be explained by magma degassing with a decrease in pressure.
The initial CO2 content of the deep basaltic magma (0.15 wt%) was estimated from the H2 O and S contents of
the inclusion in the Mg-rich olivine and the volcanic gas composition. Based on the variation in the chemicalcomposition of the melt inclusions, we propose volatile evolution of the magma plumbing system as follows, In the
deep magma chamber at depth of about 10 km, 40 wt% fractional crystallization of C magma having initial volatile
content of 3 wt% H2 O and 0.15 wt% CO2 made B magma having bulk volatile content of 5 wt% H2 O and 0.25 wt%
CO2 . This B magma ascended from the deep magma chamber to the shallow magma chamber (3-5 km depth),causing degassing of the B magma with pressure decrease. The decompression degassing decreased the volatile
content of the B magma to 3.9 wt% H2 O and 0.008 wt% CO2 . Before the 2000 eruption, the addition of CO2 -richgas to the B magma occurred in the shallow magma chamber and caused a change in the volatile content of themelt to 2.8 wt% H2 O and 0.035 wt% CO2 . In addition, the C magma ascended from the deep magma chamber andwas injected into the B magma. The mixture of the B and C magmas ascended to a depth shallower than 3 km,
accompanied by magma degassing with the pressure decrease.

©IAVCEI 2013 Scientific Assembly. All rights reserved.

540

IAVCEI 2013 Scientific Assembly - July 20 - 24, Kagoshima, Japan
Forecasting Volcanic Activity - Reading and translating the messages of nature for society

3A2_2G-O8

Room B2

Date/Time: July 23 11:00-11:15

The 2011-2012 submarine eruption of volatile-rich magma at El Hierro, Canary Islands
Marc-Antoine Longpré1 , John Stix1 , Nobumichi Shimizu2 , Andreas Klügel3
1

McGill University, Canada, 2 Woods Hole Oceanographic Institution, USA, 3 University of Bremen,
Germany
E-mail: m-a.longpre@mcgill.ca

From October 2011 to March 2012 a submarine eruption took place 2 km south of El Hierro, the youngest andwesternmost of the Canary Islands. The eruption produced buoyant, gas-filled “lava balloons” that sporadically rosefrom 100-300 m depth below sea level to the ocean surface and were sampled. Here we report ion microprobe
measurements of the volatile element concentrations (CO2, H2O, S, F, Cl) of basanite matrix glass and basanite
to phonotephrite melt inclusions trapped in olivine and Fe-Ti oxide phenocrysts collected from the glassy lava
samples. The results reveal the volatile-rich nature and degassing history of the 2011-2012 magma. Whereas
matrix glasses contain 70-710 ppm CO2, 0.4-0.9 wt.% H2O, 410-1030 ppm S, 1540-1790 ppm F and 850-1010
ppm Cl, melt inclusions show much greater ranges extending to high concentrations. Carbon dioxide concentrations
in melt inclusions exhibit extreme variations from <50 to 13700 ppm, with 50% of values above 2000 ppm CO2.
Most melt inclusions have dissolved water contents in the range 0.5-1.5 wt.%, but values of up to 3 wt.% areobserved. Sulphur ranges from 320 to 5580 ppm and is positively correlated with H2O. Fluorine and chlorine varyfrom 860 to 2110 ppm and 610 to 1370 ppm, respectively. These volatile concentrations are among the highest
ever measured for ocean island magmas. The high CO2 and H2O contents require high entrapment pressures(>200 MPa) for most melt inclusions, in agreement with fluid inclusion and clinopyroxene-melt barometry as well aswith syn-eruptive seismicity. This suggests that the volatile-rich nature of the El Hierro magma was inherited fromthe mantle source. Intense shallow level degassing probably led to powerful submarine Strombolian explosions at
El Hierro, as indicated by strong bubbling at the ocean surface. First-order calculations, using an eruptive volume of
329 million m3 (converted to 160-260 million m3 DRE assuming 20-50% porosity) determined from high-resolution
bathymetric surveys (Rivera et al., 2013) and assuming 1 wt.% CO2 and 5000 ppm S total degassing, indicate that
the El Hierro eruption could have released roughly 4-6 Tg CO2 and 2-3 Tg S to the hydrosphere and atmosphere.
However, the formation of abundant sulphide globules associated with magnetite and clinopyroxene phenocrysts
may have provided a sink for much of the sulphur. A positive correlation between S6+ /ΣS, as measured by the peakshift method, and S concentration in melt inclusions suggests that a reduction in the oxidation state of the magma
during sulphur degassing, possibly aided by extensive magnetite crystallisation, could have caused saturation witha sulphide liquid. Our findings thus have far-reaching implications for the dynamics of the 2011-2012 El Hierro
eruption, the volatile-rich nature and degassing of Canarian and other mafic alkaline magmas, and the nature of
the mantle source beneath the Canary Islands.

©IAVCEI 2013 Scientific Assembly. All rights reserved.

541

IAVCEI 2013 Scientific Assembly - July 20 - 24, Kagoshima, Japan
Forecasting Volcanic Activity - Reading and translating the messages of nature for society

3A2_2G-O9

Room B2

Date/Time: July 23 11:15-11:30

New insights on the dynamics of the most recent Plinian eruptions of Mt. Pelée(Martinique, Lesser Antilles) inferred from noble gases
Lorraine Ruzié1 , Guillaume Carazzo3 , Manuel Moreira2 , Steve Tait3 , Edouard Kaminski3
1

Department of Earth Sciences University of Manchester, United-Kingdom, 2 Géochimie et
Cosmochimie, IPGP, Sorbonne Paris Cité, Univ. Paris Diderot, France, 3 Dynamique des Fluides
Géologiques, IPGP, Sorbonne Paris Cité, Univ. Paris Diderot, France
E-mail: lorraine.ruzie@manchester.ac.uk

Mt. Pelée in Martinique is one of the most dangerous volcanoes of the Lesser Antilles arc. The May 8th, 1902
eruption that destroyed the town of St Pierre and killed 28,000 inhabitants is a famous example of its hazardous
explosive activity. Lacroix (1904) first defined the Pelean style as dome emplacement associated with lateral blast
explosions based on his pioneering description of this eruption. Among the 22 magmatic events recorded at Mt
Pelée over the last 5000 years, 6 were (Merapi-type) dome collapse eruptions and 10 were (Pelean-type) lateralblast eruptions. Furthermore, 6 eruptions were Plinian eruptions, which produced both pyroclastic flows and Pliniancolumns. Such a variability of eruptive regimes is a serious challenge for the management of volcanic hazards at
Mt. Pelée, and past eruption deposits are a crucial insight to understand the complex dynamics of this volcano.

Here we use the information recorded by the noble gases trapped inside the vesicles of pumices to study
the last three Plinian eruptions of Mt. Pelée (P1, P2, P3). During magma decompression and bubble growth,varying degrees of fractionation between the noble gases can occur because of differing diffusion coefficients anddepending on the time-scale involved. A noble gas measurement in a pumice sample thus enables us to quantify
the time elapsed between the onset of degassing and quenching due to fragmentation, for example. Type-1
eruptions (P1 and P3-1) are characterized by pumice vesicles with a low enrichment in neon compared to argon(F22 Ne <400) and 38 Ar/36 Ar ratio close to its initial value (∼0.1880). On the other hand, type-2 eruptions (P2, P3-3
and P3-2) are characterized by pumice vesicles with a high enrichment in neon compared to argon (F22 Ne >1000)
and a strongly fractionated 38 Ar/36 Ar ratio (<0.1860), rarely observed on Earth.

We interpret these fractionations as the result of two different durations for the dynamics of magma degassing.
The strong elemental and isotopic fractionations in type-2 eruptions correspond to a short time scale of degassing,and suggest that fragmentation processes occurred shortly after the onset of degassing in the conduit. Such a
rapid evolution may occur where the magma is abruptly depressurized by the collapse of a pre-existing dome, orby a sudden drop of the fragmentation level in the conduit. In type-1 eruptions, fractionations can be explained byslower degassing such that a closer approach to equilibrium between melt and bubble is achieved before quenching.

The noble gas pattern produced during magma degassing with variable time-scales can then be used as a
stratigraphic marker of different Plinian eruptions. This represents a new tool for the identification and mapping ofold fallout deposits imperfectly preserved in the field.

©IAVCEI 2013 Scientific Assembly. All rights reserved.

542

IAVCEI 2013 Scientific Assembly - July 20 - 24, Kagoshima, Japan
Forecasting Volcanic Activity - Reading and translating the messages of nature for society

3A2_2G-O10

Room B2

Date/Time: July 23 11:30-11:45

Gas geochemistry of the Copahue-Caviahue Volcanic Complex (Argentina).
Mariano Agusto1 , Franco Tassi2 , Alberto Caselli1 , Orlando Vaselli3 , Dmitri Rouwet4 , Bruno Capaccioni5 ,S Caliro6 , Giovanni Chiodini6 , T Darrah7
1

GESVA-IDEAN, Dpto. Cs. Geologicas, FCEN, Universidad de Buenos Aires. Buenos Aires, Argentina,
2
Department of Earth Sciences, University of Florence, Florence, Italy, 3 Institute of Geosciences andEarth Resources of the National Research Council (CNR-IGG), Florence, Italy, 4 Istituto Nazionale
Geofisica e Vulcanologia, Sezione di Bologna, Bologna, Italy, 5 Department of Earth andGeological-Environmental Sciences, Bologna, Italy, 6 Istituto Nazionale di Geofisica e Vulcanologia,
Osservatorio Vesuviano, Naples, Italy, 7 Division of Earth and Ocean Sciences, Nicholas School of theEnvironment, Durham, USA
E-mail: magusto@gl.fcen.uba.ar

Copahue volcano is part of the Caviahue-Copahue Volcanic Complex (CCVC), which is located in the Caviahue
volcano-tectonic caldera (Argentina-Chile), a pull-apart basin between a southern strike slip and a northern
compressive fault system, in the Southern Andean Volcanic Zone.

During the last 250 years, at least 12

low-magnitude phreatic and phreatomagmatic eruptions occurred. In 2000 a phreatomagmatic event (VEI 1-2)
caused ash fall that affected the nearby villages. Since November-December 2011 the discharge rate of fluids
from the Copahue summit has significantly increased up to December 22nd 2012, when a new phreatomagmatic
eruption occurred. In this study, the chemical and isotopic (δ13C of CO2 and CH4 , δD of CH4 and H2 O, δ18O of
H2 O, δ15N, 3He/4He and 40Ar/36Ar) compositions of fumaroles and bubbling gases collected in 2006, 2007 and2012, i.e. prior and during the last volcanic crisis, from five thermal areas surrounding the Copahue volcanic edifice
are presented and discussed. The main aims are to i) investigate the origin of fluids and their relationship with thetectonic setting, and ii) describe the evolution in fumarolic fluids chemistry and relate it to the changing volcanic
activity.
The He isotopic ratios, the highest observed for a Southern American volcano (R/Ra up to 7.94), and CO2 /3He
ratios (from 1.4 to 8.8*109 ) suggest a non-classic arc-like setting, but rather an extensional regime due toasthenospheric thinning. δ15N values (+5.3 to +5.5 ‰vs ATM) point to a source of N2 mainly from subducted
sediments. Although these gases show a clear mantle isotopic signature, magmatic gases, such as SO2 , HCl and
HF are not detected, suggesting gas scrubbing by the hydrothermal reservoir that feed CCVC. Gas geothermometry
in the H2 O-CO2 -CH4 -CO-H2 system suggests that CO and H2 re-equilibrate in a vapor phase at 200-220°C. On thecontrary, rock-fluid interactions controlling CO2 , CH4 production from Sabatier reaction and C3 H8 dehydrogenation
seem to occur within the hydrothermal reservoir at temperatures ranging from 250 to 300°C. Fumarole gases
sampled in 2006-2007 show relatively low N2 /He ratios and high R/Ra values with respect to those measured in2012 and prior to the 2000 eruption. Such compositional and isotopic variations were likely caused by an injectionof fresh He-rich magma that likely triggered the 2000 eruption. Presently it is difficult to assess the effects caused
to the hydrothermal system by the current phreatomagmatic activity. A high-frequency geochemical monitoring in
the thermal areas located at the foothills of Copahue is necessary to identify possible magmatic signals.

©IAVCEI 2013 Scientific Assembly. All rights reserved.

543

IAVCEI 2013 Scientific Assembly - July 20 - 24, Kagoshima, Japan
Forecasting Volcanic Activity - Reading and translating the messages of nature for society

3A2_2G-O11

Room B2

Date/Time: July 23 11:45-12:00

The origin of fumarolic fluids from Tupungatito Volcano (Central Chile): new insightsfrom volatile compositions
Oscar Benavente1 , Franco Tassi2 , Francisco GutiÃl’rrez1 , Orlando Vaselli2 , Felipe Aguilera3
1
2

Centro de Excelencia en Geotermia de los Andes,Universidad de Chile, Plaza Ercilla, 803, Chile,
CNR-IGG, Istituto di Geoscienze e Georisorse Via G. La Pira, 4, Firenze, Italy, 3 Departamento deGeologia, Universidad de Atacama, Copayapu 485, Copiapo, Chile
E-mail: oscar.benavente.zolezzi@gmail.com

Tupungatito is an early Pleistocene − Holocene volcano located 100 km east of Santiago, in the northernmost
sector of the South Volcanic Zone (SVZ) in Central Chile. Permanent fumarolic activity occurs at the Tupungatito
summit (Gonz á lez − Ferr á n 1995) where three crater lakes are hosted. In this study we present and discuss thevery first chemical and isotopic (δ 13C − CO2, R/Ra, and 40Ar/36Ar) composition of fumarolic gases and steam (δ 18O and δ D) collected from this volcano during two sampling campaigns carried out in February 2011 and 2012.
The main aims are to investigate the different fluid source regions and the chemical-physical processes controlling
fluid chemistry.
The chemical and isotopic data indicate that the discharged gas species and steam are likely produced by mixing
processes of fluids between a magmatic source rich in acidic gases (SO2, HCl and HF) and a meteoric − recharged
hydrothermal reservoir. The magmatic − hydrothermal fluids at the surface are affected by steam condensationthat controls the outlet fumarolic temperatures (<84 °C) favoring the dissolution of high soluble magmatic gases.
The origin of CO2 seems to be mainly related to devolatilization of the subduction carbonates, with a limited
contribution from the overlying organic − rich sediments, suggesting that the mantle source is strongly contaminatedby the slab sediments. Gas geothermometry based on the kinetically rapid H2 − H2O − CO − CO2 system
indicates equilibrium temperatures >200 °C at redox conditions more oxidizing than those commonly characterizinghydrothermal reservoirs. Reactions involving CH4 and C2 − C3 alkenes/alkanes pairs, having a relatively slow
kinetics, seem to equilibrate at greater depth where temperatures are >200 °C and redox conditions consistent withthose inferred by the presence SO2 − H2S redox pair, typical of a magmatic fluid environment. A comprehensive
conceptual geochemical model describing the circulation pattern of the Tupungatito hydrothermal − magmatic
fluids is proposed to show fluid source regions and re − equilibration processes affecting the different gas species
occurring at changing chemical − physical conditions as the magmatic − hydrothermal fluids rise up toward thesurface.
By comparing the Tupungatito gas geochemical data with those discharging from other volcanic systems locatedin the northernmost sector of the Chilean Andes, it is possible to asses that i) different climate, ii) amount andcomposition of the subducted sediment, iii) slab thermal state, and iv) crustal thickness and lithology do notapparently play a significant influence on the gas chemistry.

©IAVCEI 2013 Scientific Assembly. All rights reserved.

544

IAVCEI 2013 Scientific Assembly - July 20 - 24, Kagoshima, Japan
Forecasting Volcanic Activity - Reading and translating the messages of nature for society

3A2_2G-O12

Room B2

Date/Time: July 23 12:00-12:15

The current degassing state of Hekla volcano, Iceland
Evgenia Ilyinskaya1 , Alessandro Aiuppa2 , Baldur Bergsson3 , Thrainn Fridriksson4 , Katharina Lechner3 ,Audur Oladottir4 , Richard Yeo2 , Gaetano Giudice5
1

British Geological Survey, United Kingdom, 2 Universita di Palermo, Italy, 3 Icelandic Meteorological
Office, Iceland, 4 Iceland GeoSurvey, Iceland, 5 Istituto Nazionale di Geofisica e Vulcanologia, Italy
E-mail: evgenia@bgs.ac.uk

Hekla volcano is one of the most active and also most unpredictable volcanoes in Europe, as a precursory seismic
swarm tends to precede its eruptions by <1 hour. Since 1970, Hekla has erupted every 10 years, and is now
inflated to same level as prior to the last eruption in 2000.
There is a significant uncertainty about the depth of the magma source1,2,3,4,5 (<9 to >25 km) and the total output
of gaseous emissions both during eruptions and the quiescent intervals. It is also unknown whether the frequent
activity of Hekla during the past century is a beginning of a new eruptive trend.
In the summer of 2012 we examined gas emissions from Hekla during a quiescent interval. This was the firsttime that continuous and near real-time gas measurements were set up at an Icelandic volcano. The aims were
twofold: Firstly, to quantify the current gas release and investigate the gas source (magmatic vs hydrothermal
components); secondly to evaluate a ’proof-of-concept’ methodology for volcanic gas measurements in Icelandand thus contribute to volcanic monitoring.
Our findings showed that Hekla’s gas emissions are dominated by CO2 (flux 14 T d-1 ) which is consistent witha deep-lying magma source. Hekla’s gas emissions are proportionally significantly more CO2 rich than otherknown volcanic gas sources in Iceland. Gas is only emitted from Hekla’s top crater (last active 1980), while more
recently active craters (1991 and 2000) have higher ground temperatures, but no detectable degassing. The
isotopic signature of CO2 is magmatic, while H2 O isotopes have a more complicated behaviour and may indicate
a hydrothermal component. We believe that the elevated ground temperature at the younger craters are causedby residual heat in the erupted material from 1991 and 2000, while the gas flux in the summit crater is driven byongoing degassing of magma at depth.
The project is ongoing and now forms a part of the FUTUREVOLC, a newly commenced EU FP7 supersite project.

References: 1. Geirsson et al. 2012 JGR; 2. Ofeigsson et al. 2011. JGR 116(B5); 3. Sigmundsson et al.
1992. Geophys. Res. Lett. 19(14); 4. Soosalu and Einarsson 2004 . Bull. Volc. 66(3); 5. Sturkell et al. 2005. EOS
86(52)©IAVCEI 2013 Scientific Assembly. All rights reserved.

545

IAVCEI 2013 Scientific Assembly - July 20 - 24, Kagoshima, Japan
Forecasting Volcanic Activity - Reading and translating the messages of nature for society

3A2_2G-O13

Room B2

Date/Time: July 23 12:15-12:30

Increasing activity of Ijen Crater Lake Indonesia In 2011-2012
Sofyan Primulyana1 , Syegi Lenarahmi Kunrat2 , Ugan Boyson Saing3
1

CVGHM (Center for Volcanology and Geological Hazard Mitigation), Indonesia, 2 CVGHM (Center for
Volcanology and Geological Hazard Mitigation), Indonesia, 3 CVGHM (Center for Volcanology andGeological Hazard Mitigation), Indonesia
E-mail: sofyan@vsi.esdm.go.id

Ijen Crater Lake is located on the eastern border of Java island, Indonesia. Monitoring of volcanic activity of
Ijen Crater Lake has been done using visual observation, temperature measurement, seismicity, and changes inchemical composition. Since October 2011, the activity of Ijen Crater Lake has increase which were marked by theincreasing of seismicity. Water lake temperature increased from 27 °C up to 45 °C on March 2012. Water lake color
changes from dark green to whitish green observed in October to December 2011. On January 2012 gas bubble
observed on the surface of the lake. From January to March 2012, Chloride concentration increased from 20,934
mg/liter to 45,629 mg/liter, Sulfate concentration increased from 30,078 ppm to 57,017 ppm, the ratio of Cl/SO4
increased from 0.70 to 0.80.
The end of March 2012, activity of Ijen Crater Lake begins to decline which were characterized by the decreasingof water lake temperature into relatively stable about 35-36 °C. Gas bubble was not visible on the surface of thelake since mid-March 2012. Chloride concentration decreased from 45,629 mg/liter to 25,250 mg/liter, the ratio of
Cl/SO4 decreased from 0.80 to 0.32, whereas sulfate is still an increase up to 79,435 ppm. From May to August
2012, chloride and sulfate concentration showed a pattern indicating magmatic gasses supply is relatively stable.

©IAVCEI 2013 Scientific Assembly. All rights reserved.

546

IAVCEI 2013 Scientific Assembly - July 20 - 24, Kagoshima, Japan
Forecasting Volcanic Activity - Reading and translating the messages of nature for society

3P1_2G-O14

Room B2

Date/Time: July 23 15:00-15:15

Isobaric bubble growth and collapse in magma
Felix W von Aulock, Ben Kennedy, Christopher Oze, Paul A Ashwell
University of Canterbury, Christchurch, New ZealandE-mail: felixv.aulock@gmail.com

Bubble growth forces magma to rise in volcanic conduits, produces overpressure within the conduit and leads
to fragmentation of the melt during explosive eruptions. The three main mechanisms controlling the growth of
bubbles in melts are: (1) decompressive expansion, (2) water diffusion/exsolution related to oversaturation and(3) bubble coalescence. Magma can experience isobaric conditions as it stagnates in a magma chamber, lava
dome or post-eruptive pyroclast. In all these instances, water may diffuse in and out of bubbles despite negligible
decompression. After the melt solidifies, water gradients related to bubbles formed by dissolution and/or resorption,
are capable of preserving these periods of magma stagnation.
Here we present high-resolution water distribution data of isobaric bubble growth experiments in natural rhyolitic
samples. Bubble free aphanitic rhyolite was heated to 950°C and volume changes were visually tracked. The
samples were either just kept at 950°C for 3-24 h or were subsequently cooled to 850°C and kept for an equalamount of time before they were cooled to room temperature.
Samples show an initial volume increase of 140% - 450%, and later deflate by about 5% of the maximum volume.
Bubble sizes in the samples range between 10 µm to 1 mm. The surface of the sample consists of a thin skinof bubble-free glass that prevents the sample from deflating through a permeable network. Water gradients show
a decrease of water content across this rim to the outer surface of the sample. The background water content
of the glass ranges between 0.1-0.5 wt. %. Water content either increases or decreases around bubbles. If thesamples are heated to 950°C for only short timescales of 2-3h, water contents decrease towards the surface of the
bubble. No systematic gradients develop around bubbles in samples that were held for 24h at 950°C. Many bubbles
in samples that were cooled by 100°C and kept at this lower temperature show an increase of water in the glass
towards the surface of the bubbles.
This shows that water diffuses into vesicles during growth until equilibrium bubble size is reached when volatiles
neither exsolve nor resolve around individual bubbles. Equilibrium bubble size, however, can vary dependingon local quantities of water. The equilibrium is reached after ≤24 h at temperatures of 950°C and diffusion
homogenizes water contents and any gradients that remain from stages of bubble growth.

If the glass issubsequently cooled, the solubility of water increases and it can get resorbed into the glass.
Our experiments allow us to track the volatile diffusion around bubbles, showing the thermal history and degassing
patterns in almost completely degassed samples. This approach will serve as an important tool for the estimationof timescales and processes that control effusive and explosive volcanic eruptions.

©IAVCEI 2013 Scientific Assembly. All rights reserved.

547

IAVCEI 2013 Scientific Assembly - July 20 - 24, Kagoshima, Japan
Forecasting Volcanic Activity - Reading and translating the messages of nature for society

3P1_2G-O15

Room B2

Date/Time: July 23 15:15-15:30

Modelling gas transfer, storage and resulting displacement in a 3d permeable volcanic
edificeAmy S.D. Collinson, Jurgen W. Neuberg
University of Leeds, UK
E-mail: ee07asdc@leeds.ac.uk

We use previous experimental data on permeabilities to create 3D numerical models to investigate gas transportand storage in a permeable volcanic edifice. We combine the continuity equation, Darcy’s law and the ideal
gas law to derive a partial differential equation which is solved using a finite element method to obtain the gaspressure. The associated pressure gradient is then used within Darcy’s law to calculate the gas flux. Additionally,
we investigate how the presence of gas and variations in permeability influence the rate and degree of deformationin the volcanic edifice.

This method allows the modelling of two and three dimensional structures, both in stationary and time-dependent
evolution. Different geometries are created and the pressure and permeabilities incorporated into the model asboundary and domain conditions respectively.

We present two case studies in order to illustrated how variable permeability and pressure gradients influence
the gas flux. Firstly we investigate an event at Soufriere Hills Volcano during March 2012 which culminated insignificant ash venting. Secondly we attempt to model degassing rings on volcanoes such as Santiaguito andColima.

Our model is highly versatile and aims to shed new light on the understanding of gas storage and transport
in a permeable volcanic edifice.

©IAVCEI 2013 Scientific Assembly. All rights reserved.

548

IAVCEI 2013 Scientific Assembly - July 20 - 24, Kagoshima, Japan
Forecasting Volcanic Activity - Reading and translating the messages of nature for society

3P1_2G-O16

Room B2

Date/Time: July 23 15:30-15:45

New approach to evaluating the mass flux of volcanic fluids using the electricalconductivity structure of a volcano: application to Unzen volcano, SW Japan
Shogo Komori1 , Tsuneomi Kagiyama2 , Jerry P Fairley3
1

Institute of Earth Sciences, Academia Sinica, Taiwan, 2 Aso Volcanological Laboratory, Kyoto
University, Japan, 3 Department of Geological Sciences, University of Idaho, USA
E-mail: komori@earth.sinica.edu.tw

The efficiency of degassing of volcanic fluids in magma is one of the key parameters controlling the explosive
potentiality of the eruption and the diversity of the volcanic activity. Therefore, to evaluate the mass flux of volcanic
fluids is important in considering the constraint conditions of these phenomena. When volcanic fluids are dissolved
into the pore water of the aquifer, the aquifer has a high electrical conductivity; this is because that the pore water
conductivity is increased due to the high- salinity and temperature, and that the surface conductivity of matrix isalso increased due to hydrothermal alteration. The spatial extent of the high conductivity region could be related
to the abundance of the flux of volcanic fluids. Therefore, the electrical conductivity structure of a volcano has apotentiality for estimating the volcanic fluid mass flux by groundwater flow.

The authors developed the simple steady state model of volcanic fluids dissipation inside the aquifer, toinvestigate the factors controlling the spatial extent of the high electrical conductivity region. Firstly, the model ofthe groundwater flow was developed, to estimate the salinity and temperature distributions of the aquifer. Some
simplification were used with respect to the groundwater flow; a simple geometry and physical properties of theaquifer, and relatively little contribution of the groundwater flow from the buoyancy force. Secondly, the simple
model of the electrical conductivity was developed, to estimate the bulk electrical conductivity distribution using
the temperature and salinity distributions. This model assumes that the pore water conductivity and the surface
conductivity of matrix can be represented simply as a function of temperature and salinity of pore water.

Results showed that the spatial extent of the high electrical conductivity region is essentially controlled by
the volcanic fluids flux, rainfall recharge and aspect ratio of the aquifer, regardless of the many uncertainties ofthe parameters used. The above results were applied to the electrical conductivity structure at Unzen volcano,
SW Japan, obtained from TDEM surveys. The estimated volcanic fluids flux from magma by groundwater flow
was 105.3±0.5 t/yr. This value is quantitatively consistent with the other petrology, geochemical and geophysicalevidences; which are the spatial change of water content of magma by melt inclusion analysis, CO2 flux bygroundwater and soil analysis, and magma input rate by GPS and leveling surveys.

Recent Unzen volcano (150Ka-present) has the dome-forming eruptions; that means non-explosive activities are
dominant during recent Unzen. Our result suggests that the magma is steadily releasing the volcanic fluids at theunderground prior to eruptions. This effective degassing might lead to the decrease of water content of magma,
and be one of the reason of the non-explosive volcanism.

©IAVCEI 2013 Scientific Assembly. All rights reserved.

549

IAVCEI 2013 Scientific Assembly - July 20 - 24, Kagoshima, Japan
Forecasting Volcanic Activity - Reading and translating the messages of nature for society

3P1_2G-O17

Room B2

Date/Time: July 23 15:45-16:00

The redox state of volcanic gases: a reflection of magma depth.
Yves Moussallam1 , Clive Oppenheimer1 , Bruno Scaillet2 , Phil Kyle3 , Fabrice Gaillard2 , Nial Peters1 ,Margaret Hartley4
1

Department of Geography, University of Cambridge, Downing Place, Cambridge, CB2 3EN, UK,
ISTO, UMR 6113 Universite d’Orleans-CNRS, 1A rue de la Ferollerie, 45071 Orleans cedex 2, France,
3
Department of Earth and Environmental Science, New Mexico Institute of Mining and Technology, USA,
4
Department of Earth Sciences, University of Cambridge, Downing Place, Cambridge, CB2 3EQ, UK
2E-mail: ym286@cam.ac.uk

The combination of "Multi-gas" electrochemical sensors and open-path Fourier transform infrared spectroscopy
has made it possible to record continuous measurements of redox couples such as H2 O/H2 , SO2 /H2 S and CO2 /COin volcanic plumes. While variations through time in these ratios have been observed at volcanoes such as Erebus(Antarctica), the cause of these variations has remained uncertain. We applied Fe and S K-edge x-ray absorption
near-edge structure spectroscopy (XANES) to investigate a suite of melt inclusions in lavas belonging to the Erebus
lineage (basanite through phonolite) with entrapment depth spanning the entire lithosphere. We found that a strong
reduction of both Fe and S is associated with magma ascent and that the fO2 of the magma reduces by more that
two log units with decreasing pressure. Although the driving force behind this process cannot be unambiguously
identified, we propose that sulfur degassing is a likely explanation. This redox-depth relationship allows us to
examine the redox state of volcanic gas emissions at Erebus in terms of their last equilibration depth. In this way,
we can explain oscillatory variations in CO2 /CO and H2 O/H2 observed for the plume emitted from the Erebus lava
lake as a reflection of episodic input of magma into the lake from the underlying conduit.

©IAVCEI 2013 Scientific Assembly. All rights reserved.

550

IAVCEI 2013 Scientific Assembly - July 20 - 24, Kagoshima, Japan
Forecasting Volcanic Activity - Reading and translating the messages of nature for society

3P1_2G-O18

Room B2

Date/Time: July 23 16:00-16:15

Magma degassing, oxidation, and gas adsorption processes during a series of ash
eruptions in progress at the Sakurajima volcano, Kagoshima, Japan
Isoji MIYAGI, Hiroshi SHINOHARA, Jun’ichi ITOH
Geological Survey of Japan, Japan
E-mail: miyagi.iso14000@aist.go.jp

In order to understand magmatic processes near the top of a volcanic conduit, we examined more than 100 ash
samples from the Sakurajima volcano erupted during 1981 to 2012. We describe variations in the color and theamount of leachates for ash samples that were collected shortly after an eruption without having been exposed torain. Chemical analysis of ash leachates (Cl, F, and SO4 contents) was performed using an ion chromatographon aqueous solutions prepared from the ash and deionized water. The color analysis was performed using acolorimeter on bulk ash, on separated finer ash fractions, and on finely ground coarser ash fractions. We also
obtained SEM images, XRD on finer fractions, and EPMA data on polished ash sections, as well as time and dateof each eruption.

The amount of leachates extracted from ash sample varies by nearly three orders of magnitude over theentire range of sampled eruptions through time and exceeds, especially the sulfur, range of the same chemicalcompounds dissolved within the original melt. The long-term temporal change was observed as follows. Based on
the amount of leachates present, ash samples are classified into two major groups: one is with a molar S/Cl ratioof ∼10, and the other with S/Cl of ∼1 and that is relatively depleted in S. Ash samples erupted during 1981-1991
from the Minami-dake summit crater belong to the latter group. Ashes erupted from the Showa crater in early2008 belong the former group, of which the S content was found to decrease systematically through time, and in
2011, ashes of the latter group erupted for the first time from this crater. Based on the coloration, ash samples inthis study are classified into two groups: one is yellowish color, the other is less yellowish. The coloration of theformer group can be explained by the existence of yellowish native sulfur as well as other hydrothermally alteredminerals that were subsequently confirmed using X-ray diffractometer. Short-term temporal change was also
defined based on the following observations: (1) positive correlations between the interval of successive eruptions
and both the yellowness and the amount of ash leachates were observed; (2) the lower the total amount of ash
leachates present and the lower the yellowness of the ash; and (3) the ratio of altered to the unaltered ash particles
is higher in cases where the ash deposits resided for a longer repose time before the eruption, and this ratio drops
correspondingly (and rapidly) with a drop in the repose time.

Our interpretation is that the observed temporal changes in volcanic ash result from a transition in the amount offumarolic sulfur accumulation in partly solidified magma near the top of volcanic conduit, which may reflect themean residence time of the magma. The magma probably periodically renewed in response to ash eruption and/or
magma convection near the top of the volcanic conduit.

©IAVCEI 2013 Scientific Assembly. All rights reserved.

551

IAVCEI 2013 Scientific Assembly - July 20 - 24, Kagoshima, Japan
Forecasting Volcanic Activity - Reading and translating the messages of nature for society

3P1_2G-O19

Room B2

Date/Time: July 23 16:15-16:30

Remote temperature sensing of volcanic fumaroles using hydrogen isotopes of excess
molecular hydrogen in plumes
Urumu Tsunogai1 , Daisuke D Komatsu1 , Fumiko Nakagawa2
1

Nagoya University, Japan, 2 Hokkaido University, Japan
E-mail: urumu@nagoya-u.jp

The temperature of fumarolic gases provides important information about the magmatic/hydrothermal systems
under the volcanoes. Direct measurements on fumaroles, however, are often neither practical nor safe in most of
the active volcanoes. Remote sensing using infra-red (IR) wavelengths of surface temperatures offers an alternative
to direct measurement since the early 1960s. The IR remote sensing, however, have several problems when applied
to determine the outlet temperature of volcanic fumaroles.
In high-temperature volcanic fumaroles (>400°C), the isotopic composition (δD value) of molecular hydrogen (H2 )reaches equilibrium with that of the fumarolic H2 O under the outlet temperature so that the δD value of fumarolicH2 is a function of fumarolic temperature. Combining this temperature-dependent variation in δD value of fumarolicH2 with our high-sensitivity mass spectrometric technique which enable us to deduce the δD value of fumarolicH2 from trace H2 in the volcanic plume, we can determine the temperature at volcanic fumaroles remotely. To
ascertain that we can estimate the δD value of fumarolic H2 from those in a volcanic plume, we estimated thevalues in three fumaroles with outlet temperatures of 630°C (Tarumae), 203°C (Kuju), and 107°C (E-san). For this
we measured the concentration and δD value of H2 in each volcanic plume, along with those determined directly ateach fumarole and found a linear relationship between the depletion in the δD values of H2 in each volcanic plume,with the reciprocal of H2 concentration. Furthermore, the estimated endmember δD value for each H2 -enrichedcomponent (–260±30‰vs. VSMOW in Tarumae, –509±23‰in Kuju, and –437±14‰in E-san) coincided well withthose observed at each fumarole (–247.0±0.6‰in Tarumae, –527.7±10.1‰in Kuju, and –432.1±2.5‰in E-san).
Moreover, the calculated isotopic temperatures at the fumaroles agreed to within 20°C with the observed outlet
temperature at Tarumae and Kuju. We concluded that the δD value of the fumarolic H2 was quenched within the
volcanic plume. This enabled us to remotely estimate these in the fumarole, and thus the outlet temperature offumaroles, at least for those having the outlet temperatures more than 400°C. The remote temperature sensing
using hydrogen isotopes (HIReTS) developed in this study is widely applicable to many volcanic systems.

©IAVCEI 2013 Scientific Assembly. All rights reserved.

552

IAVCEI 2013 Scientific Assembly - July 20 - 24, Kagoshima, Japan
Forecasting Volcanic Activity - Reading and translating the messages of nature for society

3P2_2G-O20

Room B2

Date/Time: July 23 17:00-17:15

Petro-geochemical evidence for vapour transport in andesite shear fractures
Melissa Plail1 , Marie Edmonds2 , Jenni Barclay1 , Madeleine C.S. Humphreys3 , Richard A Herd1
1

University of East Anglia, UK, 2 University of Cambridge, UK, 3 University of Oxford, UK
E-mail: m.plail@uea.ac.uk

The andesitic Soufrière Hills Volcano (SHV), active since 1995, emits large fluxes of volcanic gases (dominantly
H2 O, CO2 , SO2 , HCl), even during eruptive pauses. Effective open-system degassing at dome forming eruptions
may control eruption style. It has been observed that the flux of gas is largely decoupled from the flux of magma to
the surface, indicating efficient magma-vapour segregation. Evidence for vapour transport through magma is notoften preserved in the erupted rocks, perhaps due to overprinting during eruption, or because the transport zones
themselves are not usually erupted. We present petro-geochemical evidence for vapour transport through shear
fractures in andesite at SHV and a model for their formation.
Andesite blocks in deposits from two recent eruptive events from SHV contain narrow shear zones, up to 2 m
in length and 2-10 cm in width, with alternating darker fine-grained and lighter coarser-grained bands. Analysis
has shown that the dark, fine-grained bands (grain size ∼30-70 µm) have low porosity (∼1%), oxides (<8%vol), orthopyroxene, cordierite microlites (Mg1.3-1.7 Fe0.4-0.8 Al3.7-4.04.9-5.2 O18 ), groundmass cristobalite, quartz andsieve–textured plagioclase. The light, coarse bands (grain size ∼100-350 µm) has higher porosity (7-19 vol %) andconsists of broken plagioclase, orthopyroxene, clinopyroxene and sparse large amphibole crystals, and a reduced
abundance of oxides (<2.4% vol). Glass is rare to absent in both types of band. Mineral compositions in theshear zones are identical to those established in the SHV andesite. However, bulk ICP-MS analyses indicate thatsome metal concentrations (Cu, Ni, Pb, Au and Zn) are greatly enhanced relative to the surrounding andesite. For
example, Cu and Au concentrations are up to and over ten times higher than in the andesite host. Cu is present ascopper sulphide inclusions in Ti-magnetites and plagioclase phenocrysts.
We hypothesise that the elevated metal concentrations and presence of abundant, disseminated metal-bearing
grains are evidence that these zones are relict vapour transport pathways in the shallow volcanic system. Rapid
shear of andesitic material formed brittle fractures either at the conduit wall or in the shallow dome, along which
metal-bearing vapour or fluid was transported. Partial melting occurred as a result of frictional heating during
shearing, and volatile resorption occurred as the melt cooled. The unusual presence of volcanic cordierite is likely
to have crystallised from a peraluminous partial melt that formed by preferential melting of plagioclase at elevatedtemperatures. These sheared zones provide the first petrological evidence for vapour transport at SHV, and awindow onto the early stages of mineralization at island arc volcanoes.

©IAVCEI 2013 Scientific Assembly. All rights reserved.

553

IAVCEI 2013 Scientific Assembly - July 20 - 24, Kagoshima, Japan
Forecasting Volcanic Activity - Reading and translating the messages of nature for society

3P2_2G-O21

Room B2

Date/Time: July 23 17:15-17:30

Chemical heterogeneity in rhyolite caused by magma degassing
Kim Berlo1 , Hugh Tuffen2 , Victoria Smith3 , Jonathan Castro4 , David M Pyle1 , Tamsin A Mather1 , Tina
Geraki51

Department of Earth Sciences, University of Oxford, UK, 2 Lancaster Environment Centre, Lancaster
University, UK, 3 Research Laboratory for Archaeology and the History of Art, University of Oxford, UK,
4
Institute of Geosciences, Johannes Gutenberg University Mainz, Germany, 5 Diamond Light Source,
Harwell Science and Innovation Campus, UK
E-mail: kim_berlo@inbox.com

Gas moves through magma via bubbles and fractures. During this transport (open system degassing, gas fluxing
or streaming), elements are continually redistributed between melt and gas phase. However, this redistribution
takes time and not all elements can keep up. Hence, magma is likely to be heterogeneous with respect to volatileelements. The extent of this heterogeneity is determined by the volatilities and the diffusivities of the elements, andtime. Maps of the chemical heterogeneity of magma can therefore provide an insight into the flux of gases throughmagma directly preceding an eruption.

In this contribution we show that tuffisite veins, glass-filled fractures formed when magma fragments during
deformation and degassing within the conduit, are associated with both enrichments and depletions of volatileelements. A rhyolitic tuffisite vein within an obsidian-rimmed bomb erupted from Chaitèn volcano (Chile) in 2008 isenriched in As, Pb, Zn, Sb and Mo and depleted in Li. In contrast, a tuffisite vein from Torfajökull (Iceland), from ashallow dissected lava-filled conduit, is depleted in all measured elements. Both veins locally contain vesiculated
clasts, which are enriched in volatile elements compared to the host glass.

From the spatial distribution of the chemical variations we were able to estimate a total gas flux through theveins showing that tuffisite veins form highly efficient gas pathways, which channel pre-exsolved volatiles to thesurface. We also infer significant vertical transport of clasts within interconnected tuffisite vein networks, indicatingthat degassing pathways may extend hundreds of metres below the surface.

©IAVCEI 2013 Scientific Assembly. All rights reserved.

554

IAVCEI 2013 Scientific Assembly - July 20 - 24, Kagoshima, Japan
Forecasting Volcanic Activity - Reading and translating the messages of nature for society

3P2_2G-O22

Room B2

Date/Time: July 23 17:30-17:45

The surface tension of rhyolite from combined experiments and numerical modeling
Helge M Gonnermann1 , James E Gardner2
1

Rice University, USA, 2 University of Texas, USA
E-mail: helge@rice.edu

Bubbles provide the driving force for volcanic eruptions. Consequently, it is critical to understand their nucleation,
which strongly depends on volatile supersaturation in the melt and is even more sensitive to surface tension.
The latter can be constrained from experiments, wherein small volumes of volatile-saturated melt, typically ofthe order of 0.01-0.1 cubic centimeter, are rapidly decompressed. Here, we present the results of such bubble
nucleation experiments in hydrated rhyolite, together with numerical modeling of the experiments. The numericalmodel combines classical nucleation theory with diffusive bubble growth and is constrained by the bubble number
densities and size distributions measured in the experimental charges after quenching.

From the integrated bubble nucleation and growth modeling we find that surface tension may not be constant during
the experiments, but instead increases as water diffuses from the melt into existing bubbles. This is consistent
with previous results and indicates that surface tension decreases with water content. The resultant estimates of
surface tension range between approximately 65 and 85 mN/m and are remarkably consistent across a wide rangeof water saturations and melt temperatures. Bubble nucleation in experiments with high decompression rates andlow final pressures peaks, at some time during the experiment. Subsequently nucleation rates decrease rapidly
and nucleation ends before the experimental charge is quenched. This is a consequence of high nucleation rates
and efficient water diffusion from melt into numerous existing bubbles. Once supersaturation starts to diminish
for the entire melt volume, nucleation rates plummet and nucleation ceases. In contrast, during experiments witha high final pressure, nucleation rates and bubble number density remain sufficiently low for most of the melt
to remain fully supersaturated and bubble nucleation to continue at an almost constant rate, until the sample isquenched. It is therefore important that the estimation of surface tension from nucleation experiments is based on
the actual time interval during which bubble nucleation takes place, and that it accounts for possible changes insurface tension during the experiment.

©IAVCEI 2013 Scientific Assembly. All rights reserved.

555

IAVCEI 2013 Scientific Assembly - July 20 - 24, Kagoshima, Japan
Forecasting Volcanic Activity - Reading and translating the messages of nature for society

3P2_2G-O23

Room B2

Date/Time: July 23 17:45-18:00

A condition of degassing magma deduced by the chemical and isotopic ratio of
fumarolic gas
Takeshi OHBA
Tokai University, Japan
E-mail: takeshi_ohba@tokai-u.jp

The inside of active volcano is a complex system. The chemical constituent and enthalpy are provided by adegassing magma. The degassed volatile species inevitably encounter the groundwater, resulting in the formationof magmatic-hydrothermal system. The vapor and the conjugated liquid phases co-exist in the hydrothermal
system. A part of vapor phase is discharged and noticed as fumarolic gas at surface of geothermal area. The
importance of fumarolic gas depends on the fact that fumarolic gas carries the information on degassing magmaand hydrothermal system. Among the components of volatile, SO2, H2S, HCl interact with groundwater andare modified significantly in terms of their contents. The CO2 is expected to be less modified because CO2
is less soluble in water and cannot be removed as mineral deposit in acidic environment which is typical tomagmatic-hydrothermal system. As the most abundant specie, H2O is contaminated by groundwater, however,the degree of contamination could be evaluated based on the D/H and 18O/16O ratios.
In the hydrothermal system, the dominant interactions of volatile are, the mixing with groundwater and theseparation of vapor and liquid phases. Based on the CO2/H2O ratio and isotopic ratio of H2O of fumarolic gas,
the CO2/H2O ratio of degassed volatile can be evaluated assuming the following conditions: the conservationof enthalpy, the conservation of amount and isotope for CO2 and H2O, and the equilibrated distribution of CO2
and isotope between vapor and liquid phase. The above evaluation was applied to the fumarolic gases of active
volcanoes in Japan. The CO2/H2O molar ratio was 0.03 in 1994 for the gases at Shinmoedake volcano at Kirishima,
which has erupted in 2012. The fumarolic gases at Kusatsu-Shirane and Atosanupuri results in low value as much
as 0.06. Those volcano has been dormant with persistent discharge of fumarolic gas. At Hakoke volcano, a
temporal variation in the evaluated CO2/H2O ratio has been observed. In 2001, the ratio increased to 0.021 but
deceased to 0.004 in 2005. In 2001, volcanic earthquakes were observed at Hakone volcano the number of which
was significant relative to quiescent period.
The CO2/H2O molar ratio evaluated from the composition of fumarolic gas provides a useful information for adegassing magma. The high CO2/H2O ratio of degassed gas suggests the high CO2 content in magma chamber.
As the CO2 is less soluble component in silicate melt, CO2 preferentially leaves the magma chamber throughdegassing. The increase in CO2 content in magma chamber suggest two possibilities. One is the replenishmentof new magma enriched in CO2 gas provided by a source connected to the magma chamber. Another is theaccumulation of bubbles in the roof magma chamber. In the gas phase of bubbles, CO2 is enriched relative to H2O.
The degassed gas phase contributed by the bubbles should be enriched in CO2 gas.

©IAVCEI 2013 Scientific Assembly. All rights reserved.

556

IAVCEI 2013 Scientific Assembly - July 20 - 24, Kagoshima, Japan
Forecasting Volcanic Activity - Reading and translating the messages of nature for society

3P2_2G-O24

Room B2

Date/Time: July 23 18:00-18:15

Diffusive Helium Emissions as a Precursory Sign of Volcanic Unrest at El Hierro Island,
Canary Islands, Spain
Eleazar Padron1 , Nemesio M Perez1 , Pedro A Hernandez1 , Hirochika Sumino3 , Gladys Melian1 , Jose
Barrancos1 , Dacil Nolasco1 , German Padilla1 , Samara Dionis2 , Fatima Rodriguez2 , Inigo Hernandez2 ,David Calvo2 , Keisuke Nagao3
1

Environmental Research Division, ITER, Spain, 2 Instituto VolcanolÃşgico de Canarias, Spain,3
Geochemical Research Center, University of Tokyo, Tokyo, Japan
E-mail: eleazar@iter.es

Since July 16, 2011, an anomalous seismicity at El Hierro island, the youngest and smallest of the Canary Islands,
was recorded by IGN seismic network. After the occurrence of more than 10,000 seismic events, a submarine
eruption took place 2 km off the southern coast of El Hierro Island on October 12, 2011. Frequent episodes ofturbulent gas emission and foaming, and the appearance of steamy lava fragments were observed on the sea
surface. As part of the volcanic surveillance of the island, the Instituto Volcanologico de Canarias (INVOLCAN)
geochemical monitoring program is carrying out diffuse helium surveys on the surface environment of El Hierro (soilatmosphere). This nobel gas has been investigated because it has been considered an almost ideal geochemical
indicator because it is chemically inert, physically stable, nonbiogenic, sparingly soluble in water under ambientconditions and almost non-adsorbable. The helium concentration gradients with respect to its value on air measured
at 600 sampling sites allow us to estimate a pure diffusive emission rate of helium throughout the island. Since thebeginning of the volcano-seismic unrest, 19 helium emission surveys have been carried out. The helium emission
rate has shown an excellent agreement with the evolution of the volcanic crisis of the island, reaching 30 kg/d on
October 6, several days before the occurrence of the submarine eruption. A significant decrease to 13 kg/d wasestimated almost 10 days after the beginning of the eruption, followed by a sudden increase to 38 kg/d several
days before the largest seismic event of the volcanic crisis (M = 4.6) occurred on November 11. On 5 March, thesubmarine eruption was over, but the volcanic process that started in mid-July 2011 had not finished. By the end ofJune 2012, a new seismic unrest episode occurred, accompanied by the highest deformation rate measured in theisland during the unrest period. Within this phase, a new increase on the diffusive helium emission (up to 20 kg/d)
was observed.
Helium emission data measured in El Hierro 2011-2012 volcano-seismic unrest demonstrate that diffuse helium
surveys is a powerful tool for volcano monitoring. The geochemical parameters presented here are extremely
important for forecasting the onset of volcanic unrest and subsequent volcanic eruptions, mainly when magma
migrates aseismically, i.e., silently, toward the surface.

©IAVCEI 2013 Scientific Assembly. All rights reserved.

557

IAVCEI 2013 Scientific Assembly - July 20 - 24, Kagoshima, Japan
Forecasting Volcanic Activity - Reading and translating the messages of nature for society

3P2_2G-O25

Room B2

Date/Time: July 23 18:15-18:30

Helium isotope geochemistry of thermal springs and volcanic gases from Guadeloupe,
Lesser Antilles
Philippe Jean-Baptiste1 , Patrick Allard2 , Elise Fourre1 , Lorraine Ruzie2 , Alessandro Aiuppa3 , Francesco
Parello3
1

LSCE CEA-CNRS-UVSQ/IPSL, France, 2 IPGP-CNRS, France, 3 CFTA Palermo University, Italy
E-mail: Philippe.Jean-Baptiste@cea.fr

The island of Guadeloupe is located in the middle of the 850 km long Lesser Antilles island arc. Volcanic activity isconcentrated in the southwestern part of the island (Basse Terre), with the active system of La Soufriere volcano.
Most of the thermal manifestations are located around La Soufriere dome and in the Bouillante geothermal area.
Since the last magmatic eruption in 1530, several phreatic eruptions have been recorded, with one of the mostviolent episode in 1976-1977. The Bouillante system, where a geothermal plant generates 15 MW of electrical
power, is located a few kilometers to the northwest. Between 1995 and 2012, twenty sites, including fumaroles,
bubbling gas, hot springs and production wells, were sampled on five occasions (1995 / 1996 / 1999 / 2006 / 2012)
for helium isotope geochemistry in order to map their spatial distribution and temporal trends in mantle-derived 3He
inputs across the region. The data set reveals helium (4He) concentrations in the water samples ranging from 5 to30 (10-8 cm3 STP/g) for La Soufriere volcanic system, and up to 7300 for a submarine hot spring (- 23 m) located in
the Bouillante area (Ilet Pigeon). Helium concentration in volcanic gases (fumaroles and bubbles) varies between
5.3 and 10.5 ppmv around La Soufriere, with air-corrected 3He/4He ratios in the range 7.9 - 8.4 Ra, coincident
with the MORB ratio (3He/4He = 8 Ra, where Ra = air 3He/4He ratio). In contrast, the nearby Bouillante system ischaracterized by higher helium gas contents (up to 494 ppm) and much lower 3He/4He values (between 3.3 Ra and
4.5 Ra), indicating a substantial crustal contribution to the volatile budget of the geothermal system. No temporalchange in the 3He/4He ratios over the last 16 years evidences a steady feeding source for both systems. A detailed
discussion of the helium data set will be presented and the results will be examined in relation to the geological andtectonic framework of the island of Guadeloupe.

©IAVCEI 2013 Scientific Assembly. All rights reserved.

558

IAVCEI 2013 Scientific Assembly - July 20 - 24, Kagoshima, Japan
Forecasting Volcanic Activity - Reading and translating the messages of nature for society

3P2_2G-O26

Room B2

Date/Time: July 23 18:30-18:45

Methane efflux from the soil and methanotrophic activity in volcanic-geothermal areas:
Examples from Italy and Greece
Antonina Lisa Gagliano1 , Walter D’Alessandro2 , Francesco Parello1 , Paola Quatrini3
1

University of Palermo, Dpt. DISTEM, Italy, 2 Istituto Nazionale di Geofisica e Vulcanologia, Italy,
3
University of Palermo, Dpt. STEMBIO, Italy
E-mail: w.dalessandro@pa.ingv.it

Methane plays an important role in the Earth’s atmospheric chemistry and radiative balance being the mostimportant greenhouse gas after carbon dioxide. It is released to the atmosphere by a wide number of sources,
both natural and anthropogenic, with the latter being twice as large as the former. It has recently been establishedthat significant amounts of geological methane, produced within the Earth’s crust, are currently released naturally
into the atmosphere. Active or recent volcanic-geothermal areas represent one of these sources of geologicalmethane. Due to the fact that methane flux measurements are laboratory intensive, very few data have beencollected until now and the contribution of this source has been often indirectly estimated. Both the Italian and theHellenic territories are geodynamically very active with many volcanic and geothermal areas. Here we report on
methane flux measurements made at Pantelleria (Italy), Sousaki and Nisyros (Greece). The total outputs of thesethree systems are about 10, 19 and 2 t a-1 respectively. These figures are up to one order of magnitude lower thanthose obtained through indirect estimations.
At the global scale, microbial oxidation in soils contributes to the total removal of methane from the atmosphere.
Environmental conditions in the soils of volcanic/geothermal areas (i.e.

low pH, high temperature, etc.)

have been considered inadequate for methanotrophic microrganisms. But recently, it has been demonstrated
that methanotrophic consumption in soils occurs also under such harsh conditions due to the presence ofthermo-acidophilic Verrucomicrobia.
Here we present the results of laboratory incubation experiments on soil samples collected at the main exhalative
areas that highlighted methanotrophic activity also at Pantelleria and Sousaki.
Soil metagenomic DNA was extracted from some of the Pantelleria samples and analysed using Temporal
Temperature Gradient Electrophoresis (TTGE) of the amplified Bacterial 16S rRNA gene in order to evaluate thetotal bacterial diversity. Soil DNA amplification with primers targeting Proteobacterial and Verrucomicrobial methane
monooxygenase genes (pmmo) revealed the presence of methanotrophs affiliated to both phyla up to a depth of
11 cm and a temperature of 80°C. The diversity of proteobacterial methanotrophs was investigated by creating aclone library of the amplified methane mono-oxygenase encoding gene, pmmoA. The clone sequences are close
to those of uncultured type I methanotrophic proteobacteria.
An attempt to isolate methanotrophs was carried out on soils from Pantelleria, sampled at different depths, byenrichment cultures on a mineral medium in a methane-enriched atmosphere. No isolates were obtained fromenrichments carried out at 65°C while incubation at 37°C allowed to isolate a few methanothropic strains that wereidentified as Methylocystis spp.

©IAVCEI 2013 Scientific Assembly. All rights reserved.

559

IAVCEI 2013 Scientific Assembly - July 20 - 24, Kagoshima, Japan
Forecasting Volcanic Activity - Reading and translating the messages of nature for society

3W_2G-P1

Date/Time: July 23 Poster

Vesicle evolution in magma conduits - implications for the processes of silicic magma
ascentAntonio M. Alvarez-Valero1 , Juan Gomez-Barreiro1 , Javier Borrajo2 , Carlos Montes3 , Nuria
Gomez-Gonzalez3 , Juan C. Gonzalo1 , Piedad Franco1 , Clemente Recio1 , Francisco Pla4 , Leo M.
Kriegsman5 , Asuncion Carnicero1 , Jose M. Ugidos1
1

Department of Geology, University of Salamanca, Spain, 2 Department of Physics, Engineering andMedical Radiology, University of Salamanca, Spain, 3 Department of Medical Physics, University
Hospital of Salamanca, Spain, 4 Department of Mathematics, University of Castilla-La Mancha, Spain,
5
Department of Geology, Naturalis Biodiversity Center, Netherlands
E-mail: aav@usal.es

Volcanoes commonly show two active processes, namely: (i) those occurring at depth, in mid-crustal level magma
storage zones that represent the initial state before eruption; and (ii) those occurring during ascent to the surface
which either may alter the course of an eruption already in progress or promote its triggering. The distinction
between both processes is essential to advance the knowledge on priming of a magmatic body and on how silicic
magmas evolve. As such, the role of gases and fluids is decisive.

Our knowledge of how gases behave and influence the eruptive style of magmas has greatly advanced
from sampling and observations of volcanic products; lab experiments; and numerical models. However the stateof magmatic gases and fluids just before the critical importance of the inception of the eruptive decompression isstill poorly understood and difficult to assess.

For this purpose, we present an integration of (i) direct sample observations from different depths under avolcano; (ii) microtomographic analysis (last generation of clinical TAC and micro-CT); and (iii) numericalsimulations of vesicle evolution in the magma conduit by utilizing -as input- the previous observed parameters.

©IAVCEI 2013 Scientific Assembly. All rights reserved.

560

IAVCEI 2013 Scientific Assembly - July 20 - 24, Kagoshima, Japan
Forecasting Volcanic Activity - Reading and translating the messages of nature for society

3W_2G-P2

Date/Time: July 23 Poster

Volatile and light lithophile trace element geochemistry of the 2010 eruption of Merapi
volcano revealed by melt inclusions
Katie Preece1 , Ralf Gertisser2 , Kim Berlo3 , Jenni Barclay1 , Richard Herd1
1

School of Environmental Sciences, University of East Anglia, Norwich, NR4 7TJ, UK, 2 School ofPhysical and Geographical Sciences, Keele University, Keele, Staffordshire, ST5 5BG, UK, 3 Departmentof Earth Sciences, University of Oxford, Oxford, OX1 3AN, UK
E-mail: K.Preece@uea.ac.uk

The 2010 eruption of Merapi (VEI 4) was the volcano’s largest since 1872. In contrast to recent prolonged
and effusive dome-forming eruptions at Merapi, such as the previous eruption in 2006, the 2010 eruption began
explosively, before a new dome was rapidly emplaced between 30 October and 4 November 2010. On 5 November,this new dome was destroyed by explosions, generating pyroclastic density currents (PDCs), predominantly
consisting of dark-coloured, glass-rich, dense blocks of basaltic andesite dome lava, which travelled ~16 km fromthe summit, immediately followed by PDCs characterised by scoriaceous and pumiceous clasts.
In this paper, we present volatile and light lithophile element data of clinopyroxene-hosted melt inclusions fromsamples of the dense dome lava, scoria and pumice from the PDCs generated during the peak of the 2010
eruption. SIMS analysis of volatiles (H2 O and CO2 ) and light lithophile elements (Li, B, Be) are augmented byelectron microprobe analysis of major elements and volatiles (Cl, S) in the same melt inclusions and groundmass
glass.
The melt inclusions are dacitic to rhyolitic in composition (63.3-71.8 wt.% SiO2 ) and have variable contents of
H2 O and CO2 , ranging between 0.1-3.8 wt.% and up to ~2500 ppm, respectively. The highest H2 O contents
are preserved in melt inclusions from scoriaceous and pumiceous clasts. Some melt inclusions from the pumicepreserve evidence of relatively high CO2 contents at medium (~2 wt.%) H2 O contents. Chlorine contents range
from 2000-5000 ppm and S is present in quantities up to 500 ppm in the melt inclusions, with the groundmass glassof pumice characterised by higher volatile concentrations than the groundmass of the dense dome. Light lithophileelement analyses show a moderate range in concentration in the melt inclusions of Li (15-68 ppm) and B (25-84ppm) and uniform Be concentrations (1-2 ppm).
Our data suggest that a simple model of equilibrium decompression-driven degassing cannot explain the H2 O andCO2 concentrations in the analysed melt inclusions. Instead, melt inclusion data record a complex pre-eruptive
storage and ascent history of the 2010 magma, highlighting open-system processes, including entrapment of melt
at multiple levels within the crust, enrichment of CO2 in some inclusions, and the influx and exsolution of Li-richvapours at shallow depths. Despite the more explosive nature of the 2010 eruption, melt inclusions reveal a similar
pre-eruptive volatile content to the 2006 eruption, suggesting that degassing behaviour rather than higher initial
volatiles contents, contributed to the paroxysmal 2010 eruption.

©IAVCEI 2013 Scientific Assembly. All rights reserved.

561

IAVCEI 2013 Scientific Assembly - July 20 - 24, Kagoshima, Japan
Forecasting Volcanic Activity - Reading and translating the messages of nature for society

3W_2G-P3

Date/Time: July 23 Poster

Volcanic gases as precursor of the 2010 Merapi explosive eruption
Hanik Humaida, Euis Sutaningsih, Kurniadi Rinekso, Yulianto Yulianto, Sri Hartiyatun, Elisabeth Sartini,
Rachmad Widyo Laksono
Geological Agency of Indonesia, Indonesia
E-mail: hanikhumaida@gmail.com

The 2010 Merapi explosive eruption, bearing a VEI 4, was not preceded by the formation of a lava dome. Thisphenomenon was contrary to what had normally been expected. The precursors of volcanic activity occurred ina short time. On October 26, 2010, Merapi erupted for the first time. The raising of its activity status prior to theeruption was determined according to the increase in the seismicity, deformation, as well as in the amount of the
volcanic gas emission. Pre-eruptive volcanic gas emission began to significantly changes in August, 2010, in which
the H2O concentration decreased from its normal condition, 90 % mol, down to 80 % mol. Such other gases asCO2, H2S, SO2, and HCl, also underwent a remarkable change of concentration. The HCl and SO2 ratio wasused as an initial indicator of increasing activity before eruption. It turns out that there occurred an increase inconcentration ratio of those two gases when compared with their normal condition, May 2010. The ratio of CO2
and SO2, CO2 and HCl, and CO2 and H2O also increased, serving as indicator that the source location of thosevolcanic gases had with the passage of time moved even deeper down, up to the moments when the volcano
was about to erupt. The decreasing CO2 and H2S ratio also indicated that, considering the fact that despite anincreasing pressure H2S is a stable sulphuric compound, a deeper source location was to be found. The CO2 gaschanged very significantly, and as it is characteristically magmatic with low solubility when compared with any othervolcanic gases, it was the first to be emitted. The CO2 gas concentration went up to 34 % mol and 62 % mol on 20
October 2010, higher when compared with its concentration in its normal condition, which was less than 10 % mol.
The flux of SO2 gas seems to give indication of the explosive eruption. From the long term monitoring, 1992-2009,it had different indicators between 1992-1998 and 1999-2009. It has slightly decreasing and increasing with theslope value -0.017 and 0.032 trend line of SO2 gas flux respectively. Given the description as such, it becomes
clear that the emission of volcanic gases was a clear early indication of Merapi eruption on October - November
2010.

©IAVCEI 2013 Scientific Assembly. All rights reserved.

562

IAVCEI 2013 Scientific Assembly - July 20 - 24, Kagoshima, Japan
Forecasting Volcanic Activity - Reading and translating the messages of nature for society

3W_2G-P4

Date/Time: July 23 Poster

Quantitative analysis of water concentration in melt inclusions by reflectance micro-FTIR
spectroscopy
Atsushi Yasuda
Earthquake Research Institute, Univ. Tokyo, Japan
E-mail: yasuda@eri.u-tokyo.ac.jp

A technique based on micro reflectance spectroscopy using a vacuum Fourier Transform infrared (FTIR)
spectrometer has been developed for the quantitative measurement of water content in melt inclusions inphenocrysts. Water in magma strongly affects how a volcano erupts. Thus it is important to determine the amountof water dissolved in the magma in order to predict how the eruption develops. Previously, a FTIR micro reflectancemeasurement was proposed to be a promising method to determine the concentration of water in volcanic glasses
rapidly because of its great advantage in sample preparation. It requires neither doubly polished wafers nor
measurement of sample thickness. However, application of the method to natural samples has been limited so
far because the resonance due to the O-H stretching vibration of dissolved water in the glass observed around3650cm-1 is weak. Moreover, requirement of smaller apertures for measurement of melt inclusions with several tens
micron in diameter significantly decreases the signal-to-noise ratio. Consequently quantitative analysis of water insuch a small melt inclusion was considered to be difficult. We overcome the difficulty by two improvements.
Firstly a vacuum FTIR apparatus was introduced. Evacuation the whole light path by a vacuum pump (<100Pa) can reduce more efficiently noisy absorption around 3650cm-1 due to water vapor than purging dry N2 gas.
Thirty-one glasses with various water content ranging from basaltic to rhyolitic composition were synthesized byan internal heated pressure vessel. Reflectance IR spectra were taken between 650-7000cm-1 on singly polishedglass samples. The maximum amplitude of the signal at around 3650 cm-1 resonance normalized to a baseline ofreflectivity was plotted against water contents of the samples determined by Karl-Fischer titration (ranging from 0.1
to 5.1 wt%), and a linear correlation was obtained. It appears that the slope of the correlation line slightly depends
on the bulk composition. When a reflectance spectrum is taken with a microscope aperture of 20x20 micron and1024 scans, the intensity of noise around 3650cm-1 is 0.02 (1σ), corresponding to approximately 0.2 wt% H2 O.
As the second improvement, we devised a correction method for spectrum interference by host crystal. When asmall melt inclusion is analyzed, some signal from host crystal may overlap the spectra of melt inclusion, resulting
in underestimation of water content in the melt inclusion. However, fortunately enough, most silicate crystals havedistinct reflection peaks in the region 800-1200cm-1 . Using those peaks, the contribution of host crystal to themeasured reflective spectra can be estimated within a precision of 10% relative.
Olivine-hosted melt inclusions collected from 2011 Shinmoe-dake eruption were studied as a practical applicationof the new technique.

©IAVCEI 2013 Scientific Assembly. All rights reserved.

563

IAVCEI 2013 Scientific Assembly - July 20 - 24, Kagoshima, Japan
Forecasting Volcanic Activity - Reading and translating the messages of nature for society

3W_2G-P5

Date/Time: July 23 Poster

Investigating pore-scale processes controlling the volatile transport in silicic magma
reservoirs.
Andrea Parmigiani1 , Christian Huber1 , Olivier Bachmann2
1

Georgia Institute of Technology, US, 2 ETH Zurich, Switzerland
E-mail: aparmigiani3@mail.gatech.edu

Our limited understanding of exsolved magmatic volatile phase (MVP) transport in magma reservoirs with variable
crystallinities does not allow us to constrain important concepts such as (1) how fast volatiles move in reservoirs,and (2) when and where they can accumulate. Consequently, we need more sophisticated physical models toshed light on the non-linear interactions between the exsolved MVP, silicate melts, and the crystal matrix. The
study reports the use of multiphase numerical modeling to calculate the mass transport of the MVP in a crystalline
skeleton that is initially saturated with a silicate melt. We focus on capillary channels formation of the MVP, asthese channels represent paths of low resistivity for rapid volatile transport in magmatic environment. The host
medium (crystalline matrix) can be homogeneous or display sudden transitions in crystallinity, in order to test two
potential configurations that are thought to be important in magma reservoirs: (1) high crystal content magmas(homogeneous crystal mushes) and (2) regions of transition between high crystal content magmas and a melt-richlayer (crystal-poor silicic cap overlying a mush zone).
The stability of these channels are studied in two different physical contexts, In the first experiment, we studied
the thermal reactive transport associated with the percolation of a hot buoyant volatile phase in an homogeneous
crystal-rich mush zone. In such a situation, we observe that an increase in porosity due to thermal dissolution of thecrystalline network can lead to a break-up of the volatiles capillary channels with a consequent decrease in volatileand heat flux through the system. Similar concepts can be applied to chemically reactive systems important for ore
deposit formations. In the second experiment, the MVP transport behavior at the transition from a high crystallinity
medium (crystallinty >0.5 where the volatiles mainly ascend buoyantly through the capillary channels) and a low
crystallinity medium (crystallinity

0.2) was studied. We find that capillary channels break as they penetrate into

the crystal-poor layer (capillary pinch-off). Moreover, the viscosity contrast between the MVP and the melt causesa sudden increase in viscous dissipation as the transport regime of the MVP shifts from capillary channels to
disconnected bubbles/slugs in the melt-rich layer. As a result, the MVP tends to accumulate in the melt-rich layer.
The accumulation of MVP in the crystal-poor layer can affect the physical properties of the latter, and greatly impact
the eruptibility of the system.

©IAVCEI 2013 Scientific Assembly. All rights reserved.

564

IAVCEI 2013 Scientific Assembly - July 20 - 24, Kagoshima, Japan
Forecasting Volcanic Activity - Reading and translating the messages of nature for society

3W_2G-P6

Date/Time: July 23 Poster

Automatic continuous observations of SO2 flux at Suwanose-jima volcano, Southwest
Japan
Masaaki Morita, Toshiya Mori
Geochemical Research Center, Graduate School of Science, The University of Tokyo, Japan
E-mail: morita@eqchem.s.u-tokyo.ac.jp
Suwanose-jima is a remote volcanic island (about 27 km2 in area) located about 200 km southwest of Kyushu
island, Japan. It is an andesitic volcano and, since 1950s, there has been intermittent Strombolian and Vulcanianeruptions. It is still one of the most active volcanoes in Japan that emits volcanic gas continuously. Sulfur dioxide
flux data of this volcano is rare because measurements have only been carried out once every few years for thelast 10 years. Previous studies revealed that the average SO2 flux of the volcano was 500–1000 ton/day withtypical daily variations ranging from 100 to 2000 ton/day [Mori et al., 2004; Oikawa et al., 2004].
Existing scanning DOAS systems have an outer cylinder with a window and a mirror/prism both rotating with a
stepper motor [Edmonds et al., 2003; Galle et al., 2010]. In this study, we made a small DOAS scanner replacing
the outer cylinder with a cylindrical quartz glass window. The advantage of this scanner is that it reduces power
consumption by using a relatively small stepper motor that only rotates the mirror.
The new device with a USB2000+ spectrometer (Ocean Optics, Inc.) was set about 4 km south-southwest of the
volcano on 20th January, 2013. It was powered by a solar panel and observed data were transmitted via cellular
phone networks. The measurements were carried out from 8 am to 5 pm everyday and each scan took about
10 to 15 minutes. An integrated SO2 column amount of each scan was multiplied by a wind velocity value fromweather GPV data by Japan Meteorological Agency. Preliminary results showed that average SO2 emission rates
were about 500–1000 ton/day with the maximum of 2000 ton/day. These values were comparable to those of otherrecent observations. Acquired time-series data of SO2 flux will be discussed with volcanic activities of the volcano.

References
Edmonds et al. (2003) Bull. Volcanol., 65(8), 578–586.
Galle et al. (2010) J. Geophys. Res., 115, D05304.
Mori et al. (2004) Annuals Disas. Prev. Res. Inst., Kyoto Univ, 47(C), 157–162.
Oikawa et al. (2004) Programme and Abstracts Volcanol. Soc. Japan, 66 (conference proceedings in Japanese).

©IAVCEI 2013 Scientific Assembly. All rights reserved.

565

IAVCEI 2013 Scientific Assembly - July 20 - 24, Kagoshima, Japan
Forecasting Volcanic Activity - Reading and translating the messages of nature for society

3W_2G-P7

Date/Time: July 23 Poster

Comparison of seismo-acoustic and SO2 measurement at Tungurahua volcano(Ecuador) between 2010 and 2012
Jean Battaglia1 , Silvana Hidalgo2 , Alexander L. Steele2 , Santiago Arellano3 , Mario Ruiz2 , Bo Galle3
1

Laboratoire Magmas et Volcans, CNRS UMR 6524, Univ. B. Pascal, IRD, Clermont-Ferrand, France,
2
Instituto Geofisico Escuela Politecnica Nacional, Ladron de Guevara E11-253 y Andalucia, Quito,
Ecuador, 3 Chalmers University of Technology, Gothenburg, Sweden
E-mail: battag@opgc.univ-bpclermont.fr

Tungurahua is an andesitic volcano located in Central Ecuador that has been erupting since 1999, with repeatedphases of enhanced activity during which explosions, ash emissions and occasional pyroclastic flows haveoccurred. Related to this activity the volcano emits SO2 gas plumes and various seismic signals like tremors andexplosion quakes. It is monitored by a network including up to 4 DOAS permanent NOVAC-1 type instruments,
5 broadband seismic stations coupled with infrasound sensors and 6 short period seismometers. We examinedthe data from these instruments for the period 2010-2012 with the aim of looking for a possible relation between
seismic and acoustic recordings and the amounts of SO2 emitted by the volcano.

NOVAC instruments only provide valid measurements under good weather and daylight conditions, leading
to intermittent and sometimes sparse time series. Daily average mass fluxes of SO2 have been extrapolated fromthe available measurements. Alternately, we determined the daily observed SO2 masses by summing all valid
recordings during the 10 hours of daily measurement. This approach strongly reduces SO2 measured emissions
during quiescence periods and provides time series having an improved correlation on a long time scale with theeruptive phases of the volcano. To complete the characterization of degassing we proceeded in two ways. We
first established the acoustic and seismic energies of individual explosions and calculated cumulative daily values.
Secondly, to quantify amplitudes of background tremor we calculated median amplitudes over sliding 10-minutewindows in different frequency bands.

We compared the temporal evolutions of the different seismic and acoustic parameters with the observed
SO2 emission estimates for 4 periods of enhanced activity starting in January, May and November 2010 and
May 2011. Since November 2011 until September 2012, the volcano presented an activity characterized by more
frequent and shorter periods of explosive activity. In general irregular correlations are found between seismicity
and degassing. Often temporal variations in SO2 emissions are poorly reproduced by both tremor and explosion
amplitudes, especially in terms of intensity. Large increases in explosive activity are rarely accompanied by large
increases in SO2 observed masses (January and May 2010). Degassing may persist despite significant drops
in seismicity, including background tremor (May 2010). On the other hand, rough qualitative correlations are
sometimes observed between SO2 emissions and explosive activity (November 2010), tremor (November 2011)
and sometimes with both tremor and explosions (May 2011). No better correlations are obtained when looking at
higher frequency tremor (above 5 Hz) as compared to the dominant 1-5 Hz band. Our results suggest that therelation between seismic activity and SO2 degassing may be strongly controlled by the conditions at the vent.

©IAVCEI 2013 Scientific Assembly. All rights reserved.

566

IAVCEI 2013 Scientific Assembly - July 20 - 24, Kagoshima, Japan
Forecasting Volcanic Activity - Reading and translating the messages of nature for society

3W_2G-P8

Date/Time: July 23 Poster

Gas geochemistry of geothermal fluids from the Copahue Caviahue Volcanic Complex(Argentina)
Mariano Agusto1 , Franco Tassi2 , Alberto Caselli1 , Orlando Vaselli3 , Dmitri Rouwet4 , Bruno Capaccioni5 ,Stefano Caliro6 , Giovanni Chiodini6 , Tom Darrah7
1

GESVA IDEAN, Dpto. Cs. GeolÃşgicas, FCEN, Universidad de Buenos, Argentina, 2 Department ofEarth Sciences, University of Florence, Italy, 3 Institute of Geosciences and Earth Resources of the
National Research Council (CNR IGG), Italy, 4 Istituto Nazionale Geofisica e Vulcanologia, Sezione di
Bologna„ Italy, 5 Department of Earth and Geological Environmental Sciences, Bologna, Italy, 6 Istituto
Nazionale di Geofisica e Vulcanologia, Osservatorio Vesuviano, Naples, Italy, 7 Division of Earth andOcean Sciences, Duke University, Durham, USA
E-mail: franco.tassi@unifi.it

Copahue volcano is part of the Caviahue Copahue Volcanic Complex (CCVC) which is located in
the southwestern sector of the Caviahue volcano tectonic depression. This depression is a basin accommodatingstresses between the southern Liquine Ofqui strike slip and northern Copahue Antinir compressive fault systems ina back arc setting with respect to the Southern Andean Volcanic Zone.
During the last 250 years at least 12 phreatic and phreatomagmatic eruptions occurred. In 2000 a phreatomagmatic
event caused ash falling that affected the nearby villages.
Since November 2011 the discharge rate of fluids from the Copahue summit has significantly increased up to December
2012 when a new phreatomagmatic eruption occurred. In this study the chemical and isotopic compositions offumaroles and bubbling gases collected in 2006 and 2007 and 2012 prior and during the last volcanic crisis
from five thermal areas surrounding the Copahue volcanic edifice are presented and discussed. The main
aims are to i) investigate the fluid source regions and their relationship with the peculiar tectonic assessmentof this volcano and ii) describe the chemical evolution of the fumarolic fluids caused by the ongoing activity.
The He isotopic ratios are the highest observed for a Southern American volcano (R/Ra up to 7.94). Nitrogen isotope
values (+5.3 to +5.5 ‰ vs. ATM) point to a source of nitrogen mainly from subducted sediments.
Despite these gases show a clear mantle isotopic signature magmatic gases are below the instrumental detection
limit being likely affected by scrubbing processes within a hydrothermal reservoir constituting the main source
feeding the CCVC gas discharges.
Gas geothermometry suggests that CO and hydrogen equilibrate in a vapor phase at 220 celsius degrees.
Rock fluid interactions controlling carbon dioxide and methane production from Sabatier reaction and propane
dehydrogenation seem to occur within the hydrothermal reservoir at temperatures ranging from 250 to 300 celsius degrees.
Fumarole gases sampled in 2006 and 2007 show relatively low nitrogen/He ratios and high R/Ra values withrespect to those measured in 2012 and prior to the 2000 phreatomagmatic eruption. Such compositional and isotopic
variations were likely caused by an injection of fresh magma that likely triggered the 2000 eruption.
Presently it is difficult to assess the effects caused to the hydrothermal system by the current phreatomagmatic activity.
This can likely be evaluated by intensifing the geochemical monitoring in the thermal areas located at thefoothills of Copahue to verify the presence of possible magmatic signals.

©IAVCEI 2013 Scientific Assembly. All rights reserved.

567

IAVCEI 2013 Scientific Assembly - July 20 - 24, Kagoshima, Japan
Forecasting Volcanic Activity - Reading and translating the messages of nature for society

3W_2G-P9

Date/Time: July 23 Poster

Volatile leakage from the crater bottom of Teishi Knoll of Izu-Tobu Volcanoes, Japan, 23
years after the 1989 submarine eruption
Kenji Notsu1 , Rumi Sohrin2 , Hideki Wada2 , Tatsuya Tsuboi2 , Hirochika Sumino3 , Toshiya Mori3 , Urumu
Tsunogai4 , Pedro Antonio Hernandez5 , Yusuke Suzuki6 , Ryoya Ikuta2 , Kohei Oorui1 , Masato Koyama7 ,Toshiaki Masuda2 , Naoyuki Fujii1
1

Center for Integrated Research and Education of Natural Hazards, Shizuoka University, Japan,
Institute of Geosciences, Faculty of Science, Shizuoka University, Japan, 3 Geochemical ResearchCenter, Grad. School Sci., The University of Tokyo, Japan, 4 Graduate School of Environmental Studies,
Nagoya University, Japan, 5 Environmental Research Division, ITER, Spain, 6 Izu Peninsula Geopark
Promotion Council, Japan, 7 Faculty of Education, Shizuoka University, Japan2

E-mail: k.notsu@nifty.com

A submarine eruption occurred off the Izu Peninsula, Japan, at about 18h 33m of 13 July 1989, forming Teishi Knoll(diameter about 450m, height 10m) on the seafloor at a depth of 90-100 m. Since the diameter and depth of Teishi
crater are about 200m and 10m respectively, the shallowest point of the crater rim is 81m deep and the deepest
point of the crater bottom is 122m deep. Teishi Knoll is the youngest volcano belonging to Izu-Tobu Volcanoes
consisting of more than 100 monogenetic volcanoes both on land and seafloor. The eruption was associated withintense gas emission. The released bubbles were collected from the crater bottom using an unmanned probe boat,
Dolphin 3K, on 27 Sep. 1989, and their chemical composition (volume per cent) was measured to be CO2 (23.8),
H2 (14.0), N2 (49.0), O2 (10.6) and CH4 (1.8) (Ossaka et al, Fall Meeting of Vol. Soc. Japan, Abstract No.50, 1992).
Soon after the eruption, the bubbling activity has decreased and disappeared until the end of 1991. To monitor the
volcanic activity of Teishi Knoll, seismic and geodesic observations and observation of colour of surface seawater
have been continued, but no survey has been carried out to examine volatile release from the crater bottom until
now.
In this work, we tried to detect volatile components of magmatic origin in seawater inside the Teishi crater bottom.
A plastic tube with an inner diameter of 12mm (TOYOX TG12) attached with stainless wire was thrown down fromthe deck of a small fishing boat (9-ton) to the depth at which seawater samples were collected. A CTD sensor andmetallic drag were connected to the lower end of the stainless wire. The seawater was continuously pumped out
using a tubing pump, introducing into several sample bottles. Inside the crater of Teishi Knoll, seawater samples
were collected at 3 different points just above the crater bottom (A:116-117m, B:114-115m, C:107-108m deep).
Shallower seawater samples were also collected above the crater (D:100m, E: 80m, F: 50m deep) for comparison.
For each seawater sample, dissolved CH4 content with its 13C/12C ratio, dissolved TIC (total inorganic carbon)
content with 14C content and 13C/12C ratio, dissolved organic carbon content, dissolved inorganic gases contents,
and dissolved rare gases contents with 3He/4He ratio, were measured. The CH4 contents of crater bottom samples(A-C) are 10-30 per cent higher than shallower samples (D-F), and 13C/12C ratios of CH4 in A-C samples seem tobe higher than D-F ones, suggesting the addition of CH4 originated from magmatic fluid through the crater bottom.
The 14C content and 3He/4He ratio of the bottom samples also show the magmatic fluid contribution through thecrater bottom. Considering that leaked contents of CH4 or CO2 through the crater bottom are very few, volatileemission from the Teishi magma has become extremely weak, 23 years after the eruption.

©IAVCEI 2013 Scientific Assembly. All rights reserved.

568

IAVCEI 2013 Scientific Assembly - July 20 - 24, Kagoshima, Japan
Forecasting Volcanic Activity - Reading and translating the messages of nature for society

3W_2G-P10

Date/Time: July 23 Poster

1. An increasing trend of diffuse CO2 emission from Teide volcano (Tenerife, CanaryIslands): geochemical evidence of magma degassing episodes
German D. Padilla1 , Nemesio M. Perez1 , Pedro A. Hernandez1 , Eleazar Padron1 , Gladys Melian1 , Dacil
Nolasco1 , Jose Barrancos1 , David Calvo2 , Fatima Rodriguez2 , Samara Dionis2 , Inigo Hernandez2 ,Giovanni Chiodini3
1

Environmental Research Division, ITER, Tenerife, Spain, 2 Volcanological Institute of the CanaryIslands (INVOLCAN), Tenerife, Spain, 3 Instituto Nazionale di Geofisica e Vulcanologia, Observatorio
Vesuviano, Naples, Italy
E-mail: german@iter.es

Multiple soil CO2 efflux surveys have been undertaken at the summit cone of Teide volcano, Tenerife, from 1997
to 2011, to determine the total CO2 emissions from the summit cone and to evaluate the temporal variationsof CO2 efflux and their relationships with volcano-seismic activity. Our results reveal significant fluctuations indegassing rate, which do not seem to be masked by atmospheric variations. These geochemical observations
provide evidence for the unrest of the volcanic system, as has been suggested previously by anomalous seismic
activity recorded in Tenerife during April 22-29, 2004. A new trend of increasing CO2 efflux and CO2/CH4 ratio in
fumarolic gas discharges was observed from 2006 to 2009, suggesting that subsurface magma movement is thecause for the observed changes in the total output of diffuse CO2 emission at summit cone of Teide.

©IAVCEI 2013 Scientific Assembly. All rights reserved.

569

IAVCEI 2013 Scientific Assembly - July 20 - 24, Kagoshima, Japan
Forecasting Volcanic Activity - Reading and translating the messages of nature for society

3W_2G-P11

Date/Time: July 23 Poster

Diffuse CO2 Monitoring at Cerro Negro Volcano, Nicaragua
BARRANCOS Jose1 , IBARRA Martha2 , MELIAN Gladys1 , ALVAREZ Julio2 , RODRIGUEZ Fatima3 ,NOLASCO Dacil1 , PADILLA German1 , CALVO David3 , DIONIS Samara3 , PADRON Eleazar3 ,HERNANDEZ Pedro A.3 , PEREZ Nemesio3 , MUNOZ Angelica2
1

Environmental Research Division, ITER, Tenerife/Spain, 2 Instituto Nicaraguense de Estudios
Territoriales, INETER, Managua/Nicaragua, 3 Volcanological Institute of the Canary Islands, INVOLCAN,
Tenerife/Spain
E-mail: jbarrancos@iter.es

Cerro Negro is an active basaltic volcano belonging to the active Central American Volcanic Arc which includes
a 1,100 Km long chain of 41 active volcanoes from Guatemala to Panama. Cerro Negro first erupted in 1850
and has experienced 21 eruptive eruptions with inter eruptive average periods between 7 and 9 years. Since thelast eruption occurred on 5 August 1999, with erupted lava flows and ash clouds together with gas emissions, acollaborative research program between INETER and ITER was established for monitoring diffuse CO2 emissions
from this volcano. Until 2012, twelve soil CO2 emission surveys covering an area of 0.6 km2 have been performedby means of the accumulation chamber method to evaluate the spatial and temporal variations of CO2 degassing
rate in relation to the eruptive cycle of Cerro Negro. A total diffuse CO2 emission output of 1,869 t/d was estimatedfor the 1999 survey; just 3 months after the 1999 eruption which can be considered within the post-eruptive phase.
For the April, 2002 and March, 2008 surveys, considered within the inter-eruptive phase, a clear decreasing
tendency on the total diffuse CO2 output was observed, with estimates of 431 and 10 t/d, respectively, except
a small increment in 2004, to 256 t/d, associated with an anomalous seismic activity. The higher anomalies arelocated around the crater of 1995 and 1999. An increasing on the total CO2 emission has been observed, from
December 2008 to February 2011, with total diffuse CO2 output estimates from 12 t/d to 43 t/d, respectively.
These temporal variations show a close relationship between diffuse CO2 emission and the eruptive cycle at Cerro
Negro. This relationship indicates that monitoring CO2 emission is an important geochemical tool for the volcanic
surveillance at Cerro Negro.

©IAVCEI 2013 Scientific Assembly. All rights reserved.

570

IAVCEI 2013 Scientific Assembly - July 20 - 24, Kagoshima, Japan
Forecasting Volcanic Activity - Reading and translating the messages of nature for society

3W_2G-P12

Date/Time: July 23 Poster

Mixing and degassing processes in the Skuggafjöll eruption, Iceland: Insights fromcoincident volatile and trace element melt inclusion analyses.
David A Neave1 , John Maclennan1 , Marie Edmonds1 , Thor Thordarson2
1

University of Cambridge, United Kingdom, 2 University of Iceland, IcelandE-mail: dan27@cam.ac.uk

In recent years the original, pre-eruptive CO2 contents of magmas have been calculated using CO2/Nb ratiosfrom mid-ocean ridge and ocean island lavas and melt inclusions which are believed to be un-degassed. While
this technique has the potential to be powerful for estimating volcanic CO2 fluxes from the solid earth to theatmosphere, very few studies currently exist with coincident measurement of volatile and trace elements in basaltic
melt inclusions. Flux calculations are based on the assumption that the CO2 and Nb contents of melt inclusions
are only controlled by varying amounts of fractionation and degassing. Here we present recently acquired SIMS
data obtained from a suite of olivine-hosted melt inclusions from the sub-glacial Skuggafjöll eruption in the Eastern
Volcanic Zone of Iceland, that indicate that the above mentioned assumption may not be valid. The Skuggafjöll
melt inclusions show strong correlations between trace element (e.g. Zr, Nb, La, Ce) concentrations and traceelement ratios (e.g. La/Yb) indicating variability in the composition of mantle melts supplied to the magmatic system
feeding the Skuggafjöll eruption. Both melt inclusions and matrix glasses contain ∼0.38 wt.% H2O, consistent with
rapid diffusive re-equilibration of H2O and eruption under ice. However, the CO2 concentration of melt inclusions
ranges from 200 to 1200 ppm with CO2/Nb values up to 410. CO2 concentrations correlate negatively with traceelement concentrations, linear regression of CO2 on Nb yields r = -0.76, in stark contrast with trends obtained fromexisting ‘un-degassed’ datasets. At face value this anti-correlation could be interpreted as a record of concurrent
crystallisation and degassing. However negative correlations are also observed between CO2 and trace element
ratios such as La/Yb. The most depleted, low La/Yb inclusions have the highest CO2 and the most enriched, highLa/Yb inclusions the lowest, suggesting that CO2 behaved differently in parental melts of different composition
during the formation of the Skuggafjöll magma. These observations may be accounted for by mixing of variably
degassed melts shortly prior to eruption. The most depleted inclusions record entrapment pressures of 2 kbar
using H2O-CO2 equilibrium. These melt inclusions are taken here to represent un-degassed melts on the basis of
their high CO2/Nb (>350). Consequently, they can be used to estimate total pre- and syn-eruptive CO2 emission
from the eruption. The low CO2 in enriched melt inclusions suggests that degassing has taken place to lower
their CO2/Nb. This implies that the depleted and enriched components of the Skuggafjöll magma have been
stored different pressures, and hence depths, in the crust. These observations have important implications for theinterpretation of melt inclusion data and suggest that magma mixing, as well as degassing, may be important incontrolling the volatile content of erupted melts.

©IAVCEI 2013 Scientific Assembly. All rights reserved.

571

IAVCEI 2013 Scientific Assembly - July 20 - 24, Kagoshima, Japan
Forecasting Volcanic Activity - Reading and translating the messages of nature for society

3W_2G-P13

Date/Time: July 23 Poster

Magma reservoir-vent system within Miyake-jima volcano revealed by GPS observationsof crustal deformation associated with the emission of volcanic gas
Jun Oikawa1 , Shigeru Nakao2 , Takeshi Matsushima3
1

University of Tokuo, Japan, 2 Kagoshima University, Japan, 3 Kyushyu University, Japan
E-mail: oikawa@eri.u-tokyo.ac.jp

Analysis of GPS data during the degassing stage of volcanic activity at Miyake-jima volcano, Japan, in 2000
indicates a source of crustal deformation on the south side of the summit crater wall at a depth of 5.2 km. The rateof volume fluctuation wa -3.8x105 m3 /month from September 2000 to January 2001 and -0.8x105 m3 /month fromFebruary to June 2001. As the volume is equivalent to the volume occupied by the volatile components dissolvedin the magma, it is proposed that contraction of the magma reservoir reflects degassing of its volatile components.
The observations indicate that the magma reservoir is connected to the summit crater by a magma-filled vent.
Convection within the vent carries volatile-rich magma upward to the crater, where volcanic gas is released bydegassing. The depleted magma is then carried into the magma reservoir, which contracts due to the loss ofvolume originally occupied by the volcanic gas.

©IAVCEI 2013 Scientific Assembly. All rights reserved.

572

IAVCEI 2013 Scientific Assembly - July 20 - 24, Kagoshima, Japan
Forecasting Volcanic Activity - Reading and translating the messages of nature for society

3W_2G-P14

Date/Time: July 23 Poster

Research on mud volcano in northern tianshan based on geochemistry causes
Xiaoqi Gao
Earthquake Administrator of Xinjiang Uygur Autonomous Region, China
E-mail: Gaoxq06@126.com

Mud volcano is a kind of structural geology phenomena under certain hydrogeology environment. Appearance of
mud volcano related to oil-gas belt. Gas and groundwater close to surface in some region, under pressure fromunderground, bring sediment to surface alone crack. This is the forming process of mud volcano. According to
mud volcano brought plenty of valuable information to the ground, therefore, many researchers called it "Heaven
granted well".
The consistency of mud is related to distribution of underground water. There are different kinds of mud volcano
such as: mud cone,mud shield,mud basin,mud pool and mud hole according to different mud consistency.
Mud volcano in China mainly located in Xianjiang and Taiwan. Moreover, there are some small mud volcanoes
in Tata River near Chaidamu basin margin in Qinghai province,Qu river in Sichuan basin and southern region of
Jiangsu province. Most diameter of these mud volcano pretty small.
Mud volcano in Xinjiang located in the Midwest region of Northern Tianshan,five of them were representative suchas: Horgus,Dushanzi,Wenquan,Poplar vally and Sailetike. Poplar vally and Sailetike mud volcano are the largest
mud volcanic clusterin Asia. These mud volcanoes located in axis of Northern Tianshan piedmont depression
anticline structure and exposure strata is mainly sandstone which full of underground water. The features of theseunderground water are as follow:high depression, high salinity and rich in petroleum and gas.
Mud volcanoes in Taiwan are more than twenty and mainly located in Gaoxiong and Hengchun, what’s more,
seventeen of these are in activating stage. The geological feature of these mud volcanoes are very typical andshow brilliant scenery such as flaming.
The author tested gas,fluid and solid components of mud volcanoes in the Midwest region of Northern Tianshan
from 2006 to 2012, and found geochemistry features of these mud volcanoes:
1.Mud volcanoes in Horgus,Dushanzi,Poplar vally and Sailetike have similar geochemistry features while in
Dushanzi showed some significant differences in Dushanzi.
2.The gas component of mud volcano mainly is alkane gas with about 35.6%-72.0% except mud volcano in
Wenquan.
3.The gas of mud volcanoes showed typical crust-derived helium with low 3He/4He and R/Ra value about
0.09-0.049.

©IAVCEI 2013 Scientific Assembly. All rights reserved.

573