Search results for "volcan"

The impact of Mt. Etna volcanic emissions on the atmospheric deposition: developments and improvements during three decades of studies

2022

Volcanic emissions are an important source of gases and particles to the atmosphere. Mount Etna discharges a permanent volcanic plume consisting of water vapor and gaseous species (CO2, SO2, HCl and HF, mainly), metals, acid droplets, and solid particles. This plume interacts with meteoric water during precipitations events, so the chemical signature of the plume is impressed on the rainwater. Over the past 32 years, the impact of Etna's emissions on atmospheric deposition has been investigated in many research projects by our team. Sampling methodologies and analytical procedures have been improved over the years. The first study of the concentration of water-soluble inorganic ions in week…

Plume composition changes during the birth of a new lava lake - Nyamulagira volcano, DR Congo

2016

Nyamulagira, in the Virunga Volcanic Province (VVP), Democratic Republic of Congo, is one of the most active volcanoes in Africa. The volcano is located about 25 km north-northwest of Lake Kivu in the Western Branch of the East African Rift System (EARS) with a distance of only 15 km to Nyiragongo, which is well known for its decades-old active lava lake. Nyamulagira is a shield volcano with a 3058 m high and 2000 m wide summit caldera. The volcano is characterized by frequent eruptions, which occur both from the summit crater and from the flanks (31 flank eruptions over the last 110 years). Due to the low viscosity lava, although significantly higher than the one of Nyiragongo, wide lava f…

Impact of Etna’s volcanic emission on major ions and trace elements composition of the atmospheric deposition

2022

Mt. Etna, on the eastern coast of Sicily (Italy), is one of the most active volcanoes on the planet and it is widely recognized as a big source of volcanic gases (e.g., CO2 and SO2), halogens, and a lot of trace elements, to the atmosphere in the Mediterranean region. Especially during eruptive periods, Etna’s emissions can be dispersed over long distances and cover wide areas. A group of trace elements has been recently brought to attention for their possible environmental and human health impacts, the Technology-critical elements. The current knowledge about their geochemical cycles is still scarce, nevertheless, recent studies (Brugnone et al., 2020) evidenced a contribution from the vol…

Chemistry and fluxes of major and trace element from worldwide passive degassing volcanoes: a critical review

2015

Volcanic emissions represent one of the most important natural sources of trace elements (e.g. As, Cd, Cu, Hg, Pb, Sb, Tl and Zn) into the atmosphere, sequentially influencing the hydrosphere, lithosphere and biosphere. The human health hazard during episodic volcanic eruptions generally follows from deposition of coarse and fine particles (2.5-10 and < 2.5 μm) that produces effects such as asthma and lung and respiratory disease. Regarding passive degassing volcanoes, the harmful effects of fluorine fumigation are known both for vegetation (foliar necrosis) and human/animals (fluorosis), but only a few studies have been focused on the effects of potentially toxic trace elements. From a …

A Low-Cost Smartphone Sensor-Based UV Camera for Volcanic SO2 Emission Measurements

2017

Recently, we reported on the development of low-cost ultraviolet (UV) cameras, based on the modification of sensors designed for the smartphone market. These units are built around modified Raspberry Pi cameras (PiCams; ≈USD 25), and usable system sensitivity was demonstrated in the UVA and UVB spectral regions, of relevance to a number of application areas. Here, we report on the first deployment of PiCam devices in one such field: UV remote sensing of sulphur dioxide emissions from volcanoes; such data provide important insights into magmatic processes and are applied in hazard assessments. In particular, we report on field trials on Mt. Etna, where the utility of these devices in quantif…

Devices and methods to measure H2 and CO2 concentrations in gases released from soils and low temperature fumaroles in volcanic areas

2009

A model of degassing for Stromboli volcano

2010

International audience; A better understanding of degassing processes at open-vent basaltic volcanoes requires collection of new datasets of H2O–CO2–SO2 volcanic gas plume compositions, which acquisition has long been hampered by technical limitations. Here, we use the MultiGAS technique to provide the best-documented record of gas plume discharges from Stromboli volcano to date. We show that Stromboli's gases are dominated by H2O (48–98 mol%; mean, 80%), and by CO2 (2–50 mol%; mean, 17%) and SO2 (0.2–14 mol%; mean, 3%). The significant temporal variability in our dataset reflects the dynamic nature of degassing process during Strombolian activity; which we explore by interpreting our gas m…

A CO2-gas precursor to the March 2015 Villarrica volcano eruption

2017

We present here the first volcanic gas compositional time-series taken prior to a paroxysmal eruption of Villarrica volcano (Chile). Our gas plume observations were obtained using a fully autonomous Multi-component Gas Analyser System (Multi-GAS) in the 3 month-long phase of escalating volcanic activity that culminated into the 3 March 2015 paroxysm, the largest since 1985. Our results demonstrate a temporal evolution of volcanic plume composition, from low CO$_2$/SO$_2$ ratios (0.65-2.7) during November 2014-January 2015 to CO$_2$/SO$_2$ ratios up to ≈ 9 then after. The H$_2$O/CO$_2$ ratio simultaneously declined to <38 in the same temporal interval. We use results of volatile saturatio…

Spatially resolved SO2 flux emissions from Mt Etna

2016

Abstract We report on a systematic record of SO2 flux emissions from individual vents of Etna volcano (Sicily), which we obtained using a permanent UV camera network. Observations were carried out in summer 2014, a period encompassing two eruptive episodes of the New South East Crater (NSEC) and a fissure‐fed eruption in the upper Valle del Bove. We demonstrate that our vent‐resolved SO2 flux time series allow capturing shifts in activity from one vent to another and contribute to our understanding of Etna's shallow plumbing system structure. We find that the fissure eruption contributed ~50,000 t of SO2 or ~30% of the SO2 emitted by the volcano during the 5 July to 10 August eruptive inter…

Sulfur Degassing From Steam-Heated Crater Lakes: El Chichón (Chiapas, Mexico) and Víti (Iceland)

2018

The composition of the gases released by El Chichón (Chiapas, Mexico) and Víti (Askja volcano, Iceland) volcanic lakes is examined by Multi-GAS for the first time. Our results demonstrate that H2S and SO2 are degassed by these pH 2–3 lakes. We find higher CO2/H2S and H2/H2S ratios in the lakes' emissions (31–5,685 and 0.6–35, respectively) than in the fumarolic gases feeding the lakes (13–33 and 0.08–0.5, respectively), evidencing that only a fraction (0.2–5.4% at El Chichón) of the H2S(g) contributed by the subaquatic fumaroles ultimately reaches the atmosphere. At El Chichón, we estimate a H2S output from the crater lake of 0.02–0.06 t/day. Curiously, SO2 is also detected at trace levels …