Fumaroles Research Articles

Microseismicity spectral features analysis of the Mutnovsky volcano fumarole fields area

Time-frequency analysis of 40-hour seismic records of the temporary seismological network, performed using a systematic visual inspection of seismograms, spectrograms, and signal spectra in small time windows (from 30 s to 10 min), made it possible to identify several manifestations of volcanic seismicity in the Mutnovsky fumarole field area, as well as some non-volcanic signals. The former includes signals interpreted as a volcano-tectonic earthquake (only a single event was found), multiple swarms of hybrid and long-period earthquakes, as well as a stable (constant for 40 hours) microseismic signal likely related to the gas-hydrothermal activity of fumarole fields in the northeastern crater of the volcano. For specific stations of the network, the differences between simultaneously recorded signals were considered, an assessment was made of the influence of natural factors characteristic of the study area: hydrogeological and meteorological.

Exceptional preservation of organic matter and iron-organic colloidal mineralization in hydrothermal black smoker-type sulfide mineralization from the Paleoarchean seafloor

Fossil organic matter (OM) in Paleoarchean rocks is an invaluable tracer of ancient life, yet it is often contentious due to low preservation potentials of its original organic molecular characteristics under generally high metamorphic grades. This study reports on exceptionally preserved OM within black smoker-type sulfide mineralizations from the 3.24 billion-years-old Sulphur Springs volcanic-hosted massive sulfide deposit, East Pilbara Terrane, northwestern Australia. Fine scale mineralogical and organic molecular variations – documented by SEM and TEM techniques, Raman and FTIR Spectroscopy, as well as ToF-SIMS analysis – trace the formation of millimetre-scale pyritic hydrothermal orifices. Overmature OM (≳200–250 °C) enriched in aromatic hydrocarbons occurs within earliest formed colloform-banded pyrite that could have precipitated at high temperature upon mixing of hot hydrothermal fluids with cold seawater. In contrast, mature OM (within the catagenesis window; ∼100–150 °C) with lower proportions of aromatic hydrocarbons occasionally occurs alongside pyrite within barite near the inner paleofluid conduits of the hydrothermal orifices. A deposition of this OM generation from cooler fluids enriched in sulfate during waning hydrothermal activity is corroborated by its association with original mineralogy, particularly the occurrence of isolated nanoinclusions of OM within hydrothermal barite away from grain boundaries or fissures and cracks, which renders impossible an origin from post-depositional hydrocarbon migration. When compared to the overmature OM within colloform-banded pyrite, the better-preserved inner OM not only contains less abundant, smaller, and less ordered aromatic hydrocarbons, but also higher amounts of aliphatic molecules with longer chain lengths and higher proportions of carbonyl and amide functional groups. Although the latter characteristics are consistent with contributions by microbial biomass, abiotic origins are equally plausible because hydrothermal processes can produce OM with similar organic molecular attributes. Irrespective of these uncertainties on the ultimate sourcing of OM, common intergrowths of the cooler OM with nanoscopic iron oxides – hematite and lesser magnetite – hint at its hydrothermal deposition from colloidal particles that have been stabilized by iron-organic complexation. Further research is required to ascertain the significance of this process for the hydrothermal cycling and release of organic carbons and bound iron into the Paleoarchean oceans. Collectively, our results show that ancient marine hydrothermal systems can preserve OM with differing degrees of thermal degradation, which allows for insights into its sourcing, cycling, and deposition.

Historical issues of hydrotherapy in thermal–mineral springs of the Hellenic world

Many springs have been recorded in Greece; some of them are characterized as thermo-mineral springs and are associated with their position between Eurasia and Africa, the volcanic activity, and the presence of tectonic faults. The therapeutic use of water (hydrotherapy) has been recorded in ancient Greece since at least 1000 BC. Asclepius was the god of medicine in ancient Greek religion and priests operated his worship centers (Asclepieia) offering medical services in areas with proper climatic conditions. In historical times, Hippocrates from the Aegean island of Kos (460–375 BC) is considered the father of scientific medicine as well as hydrotherapy. During the Hellenistic period, the significance of water in health was widely recognized. In the Roman era, many doctors evolved hydrotherapy treatment and the use of hot baths continued in the early Byzantine period until the sixth century AD. Finally, during the Ottoman period, the kind of respiratory bath, named Hamam, was the dominant form in public baths. Their temperature ranges between 20.5 and 83 °C, and the dominant hydrochemical type is Na-Cl. This review describes the history of hydrotherapy in Greece through the centuries, the physicochemical characteristics of thermal springs, as well as contemporary and future trends and challenges are presented.

Evolution of magma supply system beneath a submarine lava dome after the 7.3-ka caldera-forming Kikai-Akahoya eruption

Kikai caldera in SW Japan, which is a submarine volcano, has undergone repeated caldera-forming eruptions. After the 7.3-ka caldera-forming Kika-Akahoya eruption, basaltic and rhyolitic subaerial eruptions occurred at Inamura-dake, Iwo-dake and Showa-Iwojima volcanic centers on the caldera rim. Fumarole activity still continues at Iwo-dake. Recent submarine surveys have revealed that a 600 m high central lava dome grew inside the Kikai caldera, with a volume of 32 km3. In addition, several satellite volcanic cones formed to the east and the west of this central lava dome. These features inside the submarine caldera would postdate the 7.3-ka Akahoya eruption. However, the formation mechanism of these submarine volcanic edifices is yet to be well understood. Here we present the whole-rock and mineral chemistry of dredged rocks from the central lava dome and satellite volcanic cones inside the submarine caldera. The results are used to constrain magmatic conditions that formed these submarine volcanic edifices. Most rhyolites from the central lava dome and the western satellite volcanic cones are compositionally distinct from those of the Akahoya eruption and the old Iwo-dake volcanic stage (5.2–3.9 ka) rhyolites. Instead, the chemical compositions of these submarine rhyolites overlap with those of the volcanic products of the young Iwo-dake, which is active since 2.2 ka. The compositional similarity suggests that the central lava dome tapped the same magma supplying the young Iwo-dake volcanism. By contrast, the dredge samples from the eastern satellite volcanic cones exhibit binary chemical trends: one group having chemical composition that overlaps with those of the young Iwo-dake rhyolites; the other group being chemically similar to the rhyolites from the old Iwo-dake and the Akahoya eruption. The magma temperature estimated from Fe-Ti oxide thermometry (922 °C on average) is almost equal to those estimated for subaerially erupted rhyolites at Iwo-dake during the young Iwo-dake volcanic stage and the Showa-Iwojima eruption in 1934–1935. The oxygen fugacity estimated from Fe-Ti oxygen barometry is 0.8 log unit higher than Ni-NiO buffer (NNO + 0.8), on average, which is lower than that estimated for the subaerially erupted rhyolites. A magmatic hygrometer estimated H2O content of the melt ranging 2.2–3.5 wt%. Polybaric crystallization from H2O-saturated melts may have occurred beneath the submarine lava dome at depths of 2–4 km. These results suggests that a separate magma supply system with basaltic and rhyolitic magmas may exist beneath the submarine central lava dome and that underlying basaltic magma, such as that beneath Iwo-dake and Showa-Iwojima, may have heated rhyolitic magmas stored at depths of 2–4 km. Additionally, the lack of mafic enclaves, which are by contrast commonly observed in the subaerially erupted rhyolites at Iwo-dake and Showa-Iwojima on the caldera rim, implies that direct interaction between basaltic and rhyolitic magmas is limited beneath the center of the submarine caldera.

Groundwaters and deep-seated fluid circulation around Aso Volcano, Southwest Japan, revealed by multivariate statistical analysis of the geochemical data

To understand the fluid circulation under volcanoes and their surrounding area, geochemical compositions of 590 groundwater and spring/river water samples from the central Kyusyu in SW Japan, including hot and mineral spring waters around Aso and Kuju Volcanoes, have been analyzed for 12 major solutes as well as oxygen‑hydrogen and helium isotopic ratios. To extract independent processes and sources involved in formation of the groundwaters, whitened data-based k-means cluster analysis (KCA) has been applied to the data set of 12 major solutes. Eight clusters have been identified by KCA, which were mapped geographically and were compared with the isotopic compositions, temperature, and pH that were not included in KCA. By the geographical mapping, a concentric zonal structure of the clusters emerges in the Aso caldera, which resulted broadly from two fluid cycling systems from caldera rim and central cones. In the entire study area including Aso and Kuju Volcanoes, the mapping also shows geographical provenance, and the distribution of each cluster shows characteristics related to geological features, such as upwelling of deep-seated fluids along the prominent tectonic lines. On the other hand, the Piper diagram-based classification is significantly different from the KCA results and exhibits neither a concentric zonal structure within the Aso caldera nor a regional geographical provenance. These results suggest that multivariate statistical analysis such as KCA is potentially useful for investigating the origins of groundwaters and shows the advantages over classical Piper diagram-based evaluations.

Father Cícero’s water: is it really for drinking?

PurposeThis teaching case aims to provide in-class discussions on the commercialization and consumption of goods in spiritual markets. This teaching case is a narrative based on facts with a fictitious plot reporting the journeys of the launch, commercialization and consumption of mineral water in bottles in the shape of Father Cícero – a religious leader in Northeast Brazil – produced by Blue Spring Mineral Water in Juazeiro do Norte’s pilgrimage spiritual market.Design/methodology/approachPrimary and secondary data sources were gathered. Two focus groups with pilgrims and semi-structured interviews with Blue Spring leaders and a local Church representative were conducted as primary data. As secondary data, a dossier was created holding content from newspapers and blogs online on the focal product and data from the company’s official website and social networks.FindingsThroughout the case, the strategies and challenges of the production and commercialization of this religiously appealing product and the consumer practices adopted by different consumer profiles are unfolded.Originality/valueThis case intends to be a useful pedagogical tool to discuss the creation, production, commercialization and consumption of goods in spiritual markets. The case allows students to experience Blue Spring’s managers’ point of view regarding the decisions of production and commercialization of the focal product. In a broad sense, this case intends to inform future marketers of the importance of balancing commercialization in religious contexts.

Isolated occurrence of halophytic vegetation on mineral springs in the Eastern and Western Carpathians

Isolated occurrence of halophytic vegetation on mineral springs in the Eastern and Western Carpathians

Crenological Features of the Świętokrzyskie Voivodeship

On the basis analysis of 53 hydrographic maps in the scale 1:50,000, an inventory of crenological objects in the Świętokrzyskie Voivodeship was made. A total of 462 of them were identyfied. Most of them are permanent springs, precisely 346, followed by: 60 permanent springs with intakes, then 34 periodic springs, 10 spring groups, 5 bog springs, 3 mineral springs, 3 observed springs and 1 other outflow. Moreover, the studies revealed the diversity and specificity of the region in terms of crenology. Total discharge of all springs is small as it was estimated at 459.04 dm3•s–1. The most efficient springs reach about 40 dm3•s–1 and only eight exceed 20 dm3•s–1. The total discharge of the 10 most efficient outflows amount to 258.6 dm3 s-1, which accounts for 56.3% of the output in the Świętokrzyskie Voivodeship. In terms of the number of crenological objects, there is a clear difference between the mountain and highland identyfied. In the area of the Świętokrzyski National Park, 25 outflows were registered. Their total output is 6.5 dm3•s–1. At the same time, on the northern slopes of the Świętokrzyski National Park, 21 crenological objects with a total discharge of 5.5 dm3•s–1 were identyfied.

GEOLOGICAL STUDY ABOUT THE HYDROMINERAL AND GEOTHERMAL DEPOSIT CĂLIMĂNEŞTI-CĂCIULATA

This paper presents a geological study in the Călimăneşti-Căciulata area regarding mineral and geothermal waters. The detailed geological map at a scale of 1: 50000, made on the basis of detailed geological maps, is the starting material in this study. The types of water sources targeted are mineral springs, boreholes and surface water in the area. The database includes both geological and tectonic elements, as well as measurements of deuterium (δD (‰)) and overall salt content (∆d (mg/l)) expressed as the difference in density between a distilled water taken as a standard and water sample. In the case of surface water, due to the evaporation produced during the summer months which results in an enrichment in both deuterium and salts, there is a positive correlation between the values δD and Δd. If there are relationships with groundwater, correlation coefficients are low or even negative. For different water sources in the Călimănești-Căciulata area (average values), there is a good correlation between the deuterium concentration values and the global salt content. Regarding the seasonal variations, the general behavior of the groundwater in the Călimănești-Căciulata area is typical for the waters from the meteoric circuit, both according to the average values of the deuterium concentrations and according to their variations in time. The possibility of defining mixing lines of groundwater sources in this area is a criterion for integration into a single hydrodynamic system, which was formed by mixing, in different proportions, water infiltrated at high altitudes (mountain area) and water. of local infiltration, in accordance with tectonic lines and geological formations.

Kalithallite, K3Tl3+Cl6⋅2H2O, a new mineral with trivalent thallium from the Tolbachik volcano, Kamchatka, Russia

AbstractA new mineral kalithallite, K3Tl3+Cl6⋅2H2O, was found in an active fumarole belonging to the Northern fumarole field at the First scoria cone of the Northern Breakthrough of the Great Tolbachik Fissure Eruption, Tolbachik volcano, Kamchatka, Russia. Kalithallite is a product of the relatively low-temperature (70–150°C) interactions involving high-temperature sublimate minerals, volcanic gas and atmospheric water vapour. The associated minerals are cryobostryxite, KZnCl3⋅2H2O, halite, sylvite, opal and gypsum. Kalithallite forms lamellar to tabular crystals up to 5 × 30 × 40 μm combined in open-work aggregates up to 1 mm across. It is transparent, colourless in individuals and white to pale cream coloured or pale beige in aggregates, with vitreous lustre. Dcalc = 3.01 g cm–3. Kalithallite is optically uniaxial (–), ɛ = 1.656(3) and ω = 1.662(3). The chemical composition (wt.%, electron-microprobe data, H2O calculated by stoichiometry) is: K 17.72, Zn 0.85, Tl 38.76, Cl 35.91, H2Ocalc 5.99, total 99.23. The empirical formula calculated on the basis of K+Zn+Tl+Cl = 10 apfu is K2.72Zn0.06Tl1.14Cl6.08⋅2H2O. Kalithallite is tetragonal, I4/mmm, a = 15.9333(5), c = 18.1088(7) Å, V = 4595.2(4) Å3 and Z = 14. The strongest reflections of the powder X-ray diffraction (XRD) pattern [d,Å(I)(hkl)] are: 5.98(100)(202); 5.64(36)(220); 3.984(20)(400); 3.528(30)(224); 3.315(22)(422); 2.890(15)(334); and 2.817(24)(206, 440). Kalithallite is isotypical to synthetic K3Tl3+Cl6⋅2H2O. The crystal structure was refined from the powder XRD data using the Rietveld method, RBragg = 0.55%, Rp = 0.56%, and Rwp = 0.75%. The structure contains Tl3+Cl6 octahedra and K-centred polyhedra of three types: KCl8, KCl8(H2O) and KCl7(H2O)2. The mineral is named as a kalium–thallium ordered compound.

In-package pasteurization of dried basil leaves using radiofrequency heating

Recent foodborne illness outbreaks associated with the consumption of low moisture foods such as spices have emphasized concerns over microbial food safety. In-package RF pasteurization method was evaluated for inactivation of Salmonella enterica in dried basil leaves. Samples were packed in polystyrene bottle provided with a steam venting film and was either positioned vertically (electrode gap = 16 cm) or horizontally (electrode gap = 10.5 cm) for RF treatment. The horizontally placed container achieved rapid heating of dried basil leaves as compared to the vertical placement and achieved more than six log reduction of both microorganisms within 35 s of RF treatment. E. faecium was more heat resistant than Salmonella, indicating its suitability as a surrogate for RF pasteurization of dried basil leaves. Quality analysis revealed no significant (P > 0.05) change in color, total phenolics, antioxidants, and volatile composition of dried basil leaves after RF treatment. Pasteurization of final packaged food product with steam vent minimizes cross-contamination and improves food safety.

Analysis of Natural Organic Matter in Water from Cold and Hot Mineral Springs in South Korea Using 15T FT-ICR-MS.

The natural organic matter (NOM) properties in water from cold and hot mineral springs in South Korea are not well documented. We analyzed the characteristics of NOM in water from 25 cold and hot mineral springs located across South Korea. The NOM of each sample was concentrated using solid-phase extraction and analyzed using 15T Fourier-transform ion cyclotron resonance mass spectrometry. The origin of NOM was identified using van Krevelen diagrams. This study suggests that an analytical method to evaluate the characteristics of water in each region of South Korea can be established and used as a baseline for further research.

Radiation exposure of microorganisms living in radioactive mineral springs

The TIRAMISU collaboration gathers expertise from biologists, physicists, radiochemists and geologists within the Zone-Atelier Territoires Uranifères (ZATU) in France to study the response of microorganisms living in naturally radioactive mineral springs. Mineral springs are isolated ecosystems, extremely stable over geological time scales, which display different physicochemical and radiological parameters compared to their surroundings. Water and sediment samples collected in 27 mineral springs of the volcanic Auvergne region (Massif Central, France) have been analyzed for their microbial biodiversity and radionuclide content. Among the microorganisms present, diatoms (a microalgae species), widely used as environmental bioindicators of water quality, have shown to display an exceptional abundance of teratogenic forms in the most radioactive springs studied (radon activity up to 3700 Bq/L). The current work presents a first assessment of the dose received by the diatoms inhabiting naturally radioactive mineral springs. The radiological risk for microorganisms living in freshwater environments was estimated using the ERICA tool. Most of the sampled mineral springs were highly above the risk threshold of 10 mGy/h due to the large concentrations of radium in the sediments (up to 50 Bq/g). The complete radiological data on water and sediments are used as inputs to Monte Carlo simulations at micro- (GATE) and nano- (Geant4-DNA) scale in order to assess the direct and indirect damages on the diatom DNA.

Assessment of the effect of COVID-19 Lockdown on Water Quality of Baldi River Sahastradhara Sulphur Spring, Dehradun, Uttarakhand, India

Due to imposed restrictions during COVID-19 lockdown on air- rail - road traffic and industrial activities,early signs of improvement in water quality of several Indian rivers were noticed in terms of higher dissolvedoxygen and lower biochemical oxygen demand and total Coliforms, on account of least discharge of industrialeffluents and restricted human outdoor movement. In the backdrop of above, this study was aimed toassess the water quality index (WQI) of Baldi River -Sahastradhara Sulphur Spring, Dehradun, India, byfollowing the U.S. National Sanitation Foundation, NSF-WQI model, during lockdown (April to June 2020)and after unlocking process (July – September, 2020). The spatial and seasonal variations in ten waterquality parameters of Baldi River -Sahastradhara Sulphur Spring were investigated by monitoring thewater quality at three locations; Baldi river upstream, Sahastradhara proper and Baldi river downstream. Duringthe entire study period, improved water quality was observed, in terms of high DO ranging from 9.17±0.035to 8.38±0.028 mg/L and comparatively low BOD ranging from 1.68±0.032 to 2.31± 0.031 and low totalcoliform counts ranging from 06±1.09 to 31±2.75 MPN/100 mL. The NSF-WQI water quality status ofBaldi River -Sahastradhara Sulphur Spring was found to be Good all the time and the computed WQI atBaldi river upstream, Sahastradhara proper and downstream were 85.53, 83.48 and 82.30 during lockdownperiod (summer). However, during unlocking process (monsoon), due to continued weekend restrictions,on account of minimum tourists activities the water quality was still computed Good that NSF-WQI werefound to be 83.20, 80.58 and 79.27, at the studied locations respectively.

Magmatic Carbon and Helium in Springs Reveals the Vitality of a Dormant Volcano, Taranaki, New Zealand

AbstractA challenge in monitoring long‐dormant volcanoes is to discover early signs of reawakening. Mineral springs on Taranaki volcano (2,518 m, New Zealand) have elevated carbonate concentrations, δ13CDIC ∼ −5‰ (VPDB) and He isotopes from 5.13 to 5.92 RA, indicating a magmatic volatile source. Stable isotopes demonstrate water recharge occurs near the volcano's summit. Volatile anions and silica are low in a cold (5oC) flank spring at 1,000 m a.s.l., yet elevated in warm springs (25–32oC) associated with travertine deposits at 250–300 m, suggesting a weak hydrothermal component along the flow path. Tritium dating of the cold spring water yields a mean residence time of 7.8 years. This short residence time and magmatic volatile signatures suggest magmatic CO2 persistently flushes Taranaki's upper edifice. Cold spring geochemistry thus reveals volcanic activity at this dormant volcano that otherwise lacks obvious geophysical signs of unrest.

Early Precursory Changes in the 3He/4He Ratio Prior to the 2021 Tajogaite Eruption at Cumbre Vieja Volcano, La Palma, Canary Islands

AbstractWe report significant changes in the 3He/4He ratio measured at the Dos Aguas CO2‐rich cold mineral spring (La Palma, Canary Islands) that represent early precursory signals of the 2021 Tajogaite eruption at Cumbre Vieja volcano. Air‐corrected 3He/4He ratio has an average value of 9.80 RA in the last 30 years (1991–2021). Helium isotope ratios higher than the average value were observed during the period 2008–2013 suggesting an input of 3He‐rich less‐degassed magma beneath La Palma lithosphere. Magma ascended in 2017–2018 toward another reservoir located beneath Cumbre Vieja at 10–15 km depth, causing detectable seismic swarms located between 15 and 25 km, followed in 2020 by additional inputs of 3He‐rich less‐degassed magma that intruded at depth. Finally, in 2021 the buoyancy of magma and the pressure of the exsolved gases overcame the lithospheric resistance and a volcanic eruption took place between 19 September and 13 December 2021.

Study on Hydrochemical Characteristics and Formation Process of Antu Mineral Water in Changbai Mountain, China

Changbai Mountain is the source region of the Songhua, Tumen, and Yalu Rivers. It is a famous concentrated distribution area of high-quality mineral water in China, which has a great economic value. Antu County is one of the main distribution areas of basalt and mineral water in Changbai Mountain. The distribution of mineral water has a strong hydraulic relationship with surface water, which constitutes abundant recharge reserves. It is important to study the hydrochemical characteristics and the relationship between surface water and mineral water to provide a theoretical basis for further discussion on the formation process and rational utilization of mineral water resources in Changbai Mountain. A total of 18 water samples in the period of abundant and dry water were collected, including rainwater, mineral water, and surface water. Geostatistics was utilized to analyze the hydrochemical characteristics. Hydrochemical component tracing and stable environmental isotope technology with end-number calculation reveals the transformation relationship between mineral and surface water. The results indicate that: (1) The hydrochemical type is mainly HCO3-Ca-Na and HCO3-Ca-Mg type. The average content of H2SiO3 is 50.78 mg/L, which reach the standard of high quality metasilicate mineral water. (2) The mineral water formation process is dominated by the water-rock interaction in silicate mineral weathering. Metasilicate came from hydrolytic reaction of silicate and aluminosilicate under acidic conditions. (3) Atmospheric precipitation is the main recharge source, and the recharge area locates in the south nature reserve of the study area. The average retention time of mineral water is 35.5 years, and the recharge ratio of mineral water to surface water is up to 83.7%. This study will provide a theory guide for the protection and rational utilization of groundwater resources in study area and a reference for mineral spring formation study in basalt mountain area.

Red Jacket Bathed Here: Creating Race and Nation at Early National Mineral Springs

Beginning after the American Revolution, bourgeouis white northern Americans began to tell Indian origin stories about their mineral springs and spa towns. Appearing in guidebooks, periodicals, fiction, poetry, travel narratives, and scientific discourse, these origin stories had some identifiable roots in Native American practices but were largely an invention of elite white culture. They served as a neat intellectual resolution to some of the central problems of national legitimacy and national identity formation that faced the most privileged Americans. They imagined alternative non-British origin stories for shared Anglo-American cultural practices, which enabled elite white northerners to construct an alternative elite American national identity. They also established the legitimacy of white claims to an American landscape that was still in the process of being expropriated from Indians, and served to explain and deny the continued presence of Indians in white leisure spaces. The cultural script of Indian origins for Anglo-American summer leisure practices at mineral springs resolved a complex and interconnected set of cultural ambivalences through the simple, emblematic figure of an Indian at a spring.

Thermal unrest of a fumarolic field tracked using VIIRS imaging bands: The case of La fossa crater (Vulcano Island, Italy)

Detecting precursory signals before an eruption is one of the main objectives of applied volcanology. Among these signals, the variation of the emitted heat flux is certainly an important indicator of a state of disequilibrium within the magmatic system. Here we report the results of a detailed analysis of VIIRS (Visible Infrared Imaging Radiometer Suite) imaging bands (at 375 m spatial resolution) focused on measuring the Volcanic Radiative Power (VRP) emitted by the fumarole field of La Fossa crater (Vulcano Island, Italy) over the past decade (2012–2022). The analysis reveals that the long-term, steady-state VRP (baseline ∼0.17 MW) was perturbed in 2020–2021 when a prolonged period of lower than normal (<-2σ) radiant flux preceded the major unrest phase that began in mid-September 2021. By early October the anomalous VRP had peaked at ∼1.2 MW (6–8 times the baseline) then started to gradually decline in the following months. A subsequent thermal pulse was recorded in May–July 2022 and was accompanied by a period of seawater discoloration that affected the Baia di Levante (a shallow sea bay ∼1.4 km north of La Fossa crater). The concomitance of these phenomena suggests the occurrence of a second pressurization phase driven by the arrival of deep magmatic fluids within both the central and distal degassing fumarolic zones. These results provide a complementary, important contribution to the understanding of the unrest of La Fossa crater and highlight the potential of VIIRS in detecting pre-eruptive signals at other poorly-monitored volcanoes characterized by high-temperature fumarolic activity.

Feasibility study and 3E analysis of blowdown heat recovery in a combined cycle power plant for utilization in Organic Rankine Cycle and greenhouse heating

Greenhouse heating plays a key role in the growth and yield of greenhouse crops in cold regions. Moreover, heat loss and energy wastage are abundant in the industry. Therefore, these two subjects are combined in this study to analyze the feasibility of using the steam vent and waste drain flow of a blowdown tank in a combined cycle power plant (CCPP) to provide the required additional heating in a greenhouse by installing a radiant floor heating (RFH) system. For this purpose, a tunnel greenhouse with an east-west orientation is modeled in steady states. In addition, a CCPP integrated with the Organic Rankine Cycle (ORC) is modeled on the energy, exergy, and economic (3E) analysis to comprehensively evaluate the system. The effect of greenhouse heating was analyzed in three months of the year with highest heating demand. According to the results of analyzing four scenarios, the RFH system managed to increase the greenhouse temperature up to 7.5 °C. The results indicated an increase in energy efficiency and exergy efficiency of the system by 0.04% and 0.05%, respectively. Based on the economic analysis, the payback period in the proposed scenario was determined 4.81 years.