scholarly journals Behavior of magmatic components in fumarolic gases related to the 2018 phreatic eruption at Ebinokogen Ioyama volcano, Kirishima Volcanic Group, Kyushu, Japan

2021 ◽  
Vol 73 (1) ◽  
Author(s):  
Takeshi Ohba ◽  
Muga Yaguchi ◽  
Urumu Tsunogai ◽  
Masanori Ito ◽  
Ryo Shingubara
Keyword(s):  
Hot Spring ◽  
Equilibrium Temperature ◽  
Phreatic Eruption ◽  
Vapor Flux ◽  
High Enthalpy ◽  
Liquid Phases ◽  
Direct Sampling ◽  
Fumarolic Gases ◽  
Apparent Equilibrium ◽  
Fumarolic Gas

AbstractDirect sampling and analysis of fumarolic gas was conducted at Ebinokogen Ioyama volcano, Japan, between December 2015 and July 2020. Notable changes in the chemical composition of gases related to volcanic activity included a sharp increase in SO2 and H2 concentrations in May 2017 and March 2018. The analyses in March 2018 immediately preceded the April 2018 eruption at Ioyama volcano. The isotopic ratios of H2O in fumarolic gas revealed the process of formation. Up to 49% high-enthalpy magmatic vapor mixed with 51% of cold local meteoric water to generate coexisting vapor and liquid phases at 100–160 °C. Portions of the vapor and liquid phases were discharged as fumarolic gases and hot spring water, respectively. The CO2/SO2 ratio of the fumarolic gas was higher than that estimated for magmatic vapor due to SO2 hydrolysis during the formation of the vapor phase. When the flux of the magmatic vapor was high, effects of hydrolysis were small resulting in low CO2/SO2 ratios in fumarolic gases. The high apparent equilibrium temperature defined for reactions involving SO2, H2S, H2 and H2O, together with low CO2/SO2 and H2S /SO2 ratios were regarded to be precursor signals to the phreatic eruption at Ioyama volcano. The apparent equilibrium temperature increased rapidly in May 2017 and March 2018 suggesting an increased flux of magmatic vapor. Between September 2017 and January 2018, the apparent equilibrium temperature was low suggesting the suppression of magmatic vapor flux. During this period, magmatic eruptions took place at Shinmoedake volcano 5 km away from Ioyama volcano. We conclude that magma sealing and transport to Shinmoedake volcano occurred simultaneously in the magma chamber beneath Ioyama volcano.

scholarly journals Trace Elements and Minerals in Fumarolic Sulfur: The Case of Ebeko Volcano, Kuriles

Geofluids ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-16 ◽  
Author(s):  
E. P. Shevko ◽  
S. B. Bortnikova ◽  
N. A. Abrosimova ◽  
V. S. Kamenetsky ◽  
S. P. Bortnikova ◽  
...  
Keyword(s):  
Low Temperature ◽  
Metal Sulfides ◽  
Native Sulfur ◽  
Ambient Temperatures ◽  
Elemental Abundances ◽  
Chalcophile Elements ◽  
Fumarolic Gases ◽  
Sulfur Deposits ◽  
Low Solubility ◽  
Fumarolic Gas

Native sulfur deposits on fumarolic fields at Ebeko volcano (Northern Kuriles, Russia) are enriched in chalcophile elements (As-Sb-Se-Te-Hg-Cu) and contain rare heavy metal sulfides (Ag2S, HgS, and CuS), native metal alloys (Au2Pd), and some other low-solubility minerals (CaWO4, BaSO4). Sulfur incrustations are impregnated with numerous particles of fresh and altered andesite groundmass and phenocrysts (pyroxene, magnetite) as well as secondary minerals, such as opal, alunite, and abundant octahedral pyrite crystals. The comparison of elemental abundances in sulfur and unaltered rocks (andesite) demonstrated that rock-forming elements (Ca, K, Fe, Mn, and Ti) and other lithophile and chalcophile elements are mainly transported by fumarolic gas as aerosol particles, whereas semimetals (As, Sb, Se, and Te), halogens (Br and I), and Hg are likely transported as volatile species, even at temperatures slightly above 100°C. The presence of rare sulfides (Ag2S, CuS, and HgS) together with abundant FeS2 in low-temperature fumarolic environments can be explained by the hydrochloric leaching of rock particles followed by the precipitation of low-solubility sulfides induced by the reaction of acid solutions with H2S at ambient temperatures. The elemental composition of native sulfur can be used to qualitatively estimate elemental abundances in low-temperature fumarolic gases.

Noble gas and stable isotope geochemistry of thermal fluids from Deception Island, Antarctica

2009 ◽  
Vol 21 (3) ◽  
pp. 255-267 ◽  
Author(s):  
Minoru Kusakabe ◽  
Keisuke Nagao ◽  
Takeshi Ohba ◽  
Jung Hun Seo ◽  
Sung-Hyun Park ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Hydrothermal System ◽  
Hot Spring ◽  
Isotope Geochemistry ◽  
Noble Gas ◽  
Deception Island ◽  
Rock Interaction ◽  
Thermal Fluids ◽  
Back Arc ◽  
Fumarolic Gas

AbstractNew stable isotope and noble gas data obtained from fumarolic and bubbling gases and hot spring waters sampled from Deception Island, Antarctica, were analysed to constrain the geochemical features of the island's active hydrothermal system and magmatism in the Bransfield back-arc basin. The 3He/4He ratios of the gases (< 9.8 × 10-6), which are slightly lower than typical MORB values, suggest that the Deception Island magma was generated in the mantle wedge of a MORB-type source but the signature was influenced by the addition of radiogenic 4He derived from subducted components in the former Phoenix Plate. The N2/He ratios of fumarolic gas are higher than those of typical mantle-derived gases suggesting that N2 was added during decomposition of sediments in the subducting slab. The δ13C values of -5 to -6‰ for CO2 also indicate degassing from a MORB-type mantle source. The H2/Ar- and SiO2 geothermometers indicate that the temperatures in the hydrothermal system below Deception Island range from ~150°C to ~300°C. The δD and δ18O values measured from fumarolic gas and hot spring waters do not indicate any contribution of magmatic water to the samples. The major ionic components and δD-δ18O-δ34S values indicate that hot spring waters are a mixture of local meteoric water and seawater. Mn and SiO2 in spring waters were enriched relative to seawater reflecting water-rock interaction at depth.

scholarly journals Evaporation of Nonequilibrium Raindrops as a Fog Formation Mechanism

2010 ◽  
Vol 67 (2) ◽  
pp. 345-364 ◽  
Author(s):  
Robert Tardif ◽  
Roy M. Rasmussen
Keyword(s):  
Sensible Heat Flux ◽  
Nonequilibrium State ◽  
Ambient Air ◽  
Equilibrium Temperature ◽  
Terminal Velocity ◽  
Fog Water ◽  
Light Rain ◽  
Vapor Flux ◽  
Patterns Of Behavior ◽  
Latent Heat Loss

Abstract To gain insights into the poorly understood phenomenon of precipitation fog, this study assesses the evaporation of freely falling drops departing from equilibrium as a possible contributing factor to fog formation in rainy conditions. The study is based on simulations performed with a microphysical column model describing the evolution of the temperature and mass of evaporating raindrops within a Lagrangian reference frame. Equilibrium defines a state where the latent heat loss of an evaporating drop is balanced by the sensible heat flux from the ambient air, hence defining a steady-state drop temperature. Model results show that the assumption of equilibrium leads to small but significant errors in calculated precipitation evaporation rates for drops falling in continuously varying ambient near-saturated or saturated conditions. Departure from equilibrium depends on the magnitude of the vertical gradients of the ambient temperature and moisture as well as the drop-size-dependent terminal velocity. Contrasting patterns of behavior occur depending on the stratification of the atmosphere. Raindrops falling in inversion layers remain warmer than the equilibrium temperature and lead to enhanced moistening, with supersaturation achieved when evaporation proceeds in saturated inversions. Dehydration occurs in layers with temperature and water vapor increasing with height due to the vapor flux from the environment to the colder drops. These contrasts are not represented when equilibrium is assumed. The role of nonequilibrium raindrop evaporation in fog occurrences is further emphasized with simulations of a case study characterized by fog forming under light rain falling in a developing frontal inversion. Good agreement is obtained between fog water content observations and simulations representing only the effects of rainfall evaporation. This study demonstrates the need to take into account the nonequilibrium state of falling raindrops for a proper representation of an important mechanism contributing to precipitation fog occurrences.

Variations in thermal state revealed by the geochemistry of fumarolic gases and hot-spring waters of the Tateyama volcanic hydrothermal system, Japan

2019 ◽  
Vol 81 (2) ◽  
Author(s):  
Kaori Seki ◽  
Takeshi Ohba ◽  
Shinnosuke Aoyama ◽  
Yuichiro Ueno ◽  
Hirochika Sumino ◽  
...  
Keyword(s):  
Hydrothermal System ◽  
Thermal State ◽  
Hot Spring ◽  
Fumarolic Gases

scholarly journals KARAKTERISTIK FLUIDA DAN GAS PANAS BUMI SEBAGAI PENGARUH PENINGKATAN AKTIVITAS VULKANIK GUNUNGAPI SLAMET (Characteristic Of Geothermal Fluid And Gas Induced By Increased Volcanic Activity Of Slamet Volcano)

2015 ◽  
Vol 5 (3) ◽  
Author(s):  
Mamay Surmayadi
Keyword(s):  
Hot Spring ◽  
Geothermal System ◽  
Volcanic Earthquake ◽  
Geothermal Systems ◽  
Geothermal Fluid ◽  
High Enthalpy ◽  
Central Java ◽  
Volcano Seismicity ◽  
The Status ◽  
Calcite Saturation

AbstrakSejak awal Maret 2014 status aktifitas Gunungapi Slamet di Jawa Tengah dinaikan dari Normal menjadi Waspada seiring dengan peningkatan jumlah gempa vulkanik. Seismisitas Gunungapi Slamet memperlihatkan gempa letusan 1106 kejadian dan gempa hembusan 6857 per hari.  Sementara itu,  gempa vulkanik dalam hanya terekam 2 kali selama periode Maret – Agustus 2014. Sumber gempa berada pada kedalaman antara 1 - 2 km di bawah kawah Gunungapi Slamet sebagai indikasi gempa permukaan. Peningkatan aktifitas vulkanik Slamet menghasilkan pelepasan gas CO2 yang berpengaruh terhadap fluida panas bumi yang ditunjukan dengan terjadinya perubahan keasaman air dari normal menjadi alkalin, pembentukan bualan gas CO2 pada air panas Pancuran 3 di Baturraden, dan peningkatan saturasi kalsit.  Bualan gas CO2 menjadi indikasi terjadinya proses pendidihan pada temperatur 273 C pada kedalaman 454 m di bawah permukaan laut. Kondisi ini menjadikan temperatur reservoir lebih tinggi sebagai indikasi sistem panas bumi Gunungapi Slamet merupakan sistem panas bumi aktif bertemperatur tinggi. Kata kunci : gempa permukaan, fluida panas bumi, bualan gas, saturasi kalsitAbstractSince the beginning of March 2014 the status of activities Slamet volcano in Central Java has been declared from Normal becomes Alert due to significant increase in the number of volcanic earthquakes. Slamet volcano seismicity shows eruption earthquakes as many as 1106, and gas emission earthquakes as many as 6857 events per day. Meanwhile, the deep volcanic earthquake recorded only 2 times during the period March to August 2014. The hypocentre of these earthquake was at a depth of 1-2 km below Slamet volcano crater as an indication of the surface earthquakes.Increased magmatic activity resulted in the release of CO2 gas effect on the geothermal fluid which is indicated by changes in water acidity from normal to alkaline, formation of CO2 bubble gas on Pancuran 3 hot spring at Baturraden area, and calcite saturation enhancement. The presence of CO2 bubble gas is indication of boiling at temperatures 273 C at a depth of 454 m below sea level. This condition makes the reservoir temperature becomes higher as indication that the geothermal system of Slamet volcano is active geothermal systems with high temperature (high enthalpy).Keywords: surface earthquake, geothermal fluid, bubble gas.

scholarly journals Source constraints for the 2015 phreatic eruption of Hakone volcano, Japan, based on geological analysis and resistivity structure

2019 ◽  
Vol 71 (1) ◽  
Author(s):  
Kazutaka Mannen ◽  
Toshikazu Tanada ◽  
Akira Jomori ◽  
Takashi Akatsuka ◽  
George Kikugawa ◽  
...  
Keyword(s):  
Ground Deformation ◽  
Phreatic Eruption ◽  
Mineral Precipitation ◽  
Hakone Volcano ◽  
Vapor Flux ◽  
Conductive Body ◽  
Before And After ◽  
Sealing Zone ◽  
Center Area ◽  
Geological Analysis

AbstractOn June 29, 2015, a small phreatic eruption occurred in the most intensively steaming area of Hakone volcano, Japan. A previous magnetotelluric survey for the whole volcano revealed that the eruption center area (ECA) was located near the apex of a bell-shaped conductive body (resistivity < 10 Ωm) beneath the volcano. We performed local, high-resolution magnetotelluric surveys focusing on the ECA before and after the eruption. The results from these, combined with our geological analysis of samples obtained from a steam well (500 m deep) in the ECA, revealed that the conductive body contained smectite. Beneath the ECA, however, the conductive body intercalated a very local resistive body located at a depth of approximately 150 m. This resistive body is considered a vapor pocket. For the 2 months prior to eruption, a highly localized uplift of the ECA had been observed via satellite InSAR. The calculated depth of the inflation source was coincident with that of the vapor pocket, implying that enhanced vapor flux during the precursory unrest increased the porosity and vapor content in the vapor pocket. In fact, our magnetotelluric survey indicated that the vapor pocket became inflated after the eruption. The layer overlaying the vapor pocket was characterized by the formation of various altered minerals, and mineral precipitation within the veins and cracks in the layer was considered to have formed a self-sealing zone. From the mineral assemblage, we conclude that the product of the 2015 eruption originated from the self-sealing zone. The 2015 eruption is thus considered a rupture of the vapor pocket only 150 m below the surface. Even though the eruption appeared to have been triggered by the formation of a considerably deeper crack, as implied by the ground deformation, no geothermal fluid or rocks from significantly deeper than 150 m were erupted.

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