ALBERT

Description: The Nevado del Ruiz volcano is considered one of the most active volcanoes in Colombia, which can potentially threaten approximately 600,000 inhabitants. The existence of a glacier and several streams channelling in some main rivers, flowing downslope, increases the risk for the population living on the flank of the volcano in case of unrest, because of the generation of lahars and mudflows. Indeed, during the November 1985 subplinian eruption, a lahar generated by the sudden melting of the glacier killed twenty thousand people in the town of Armero. Moreover, the involvement of the local hydrothermal system has produced in the past phreatic and phreatomagmatic activity, as occurred in 1989. Therefore, the physico-chemical conditions of the hydrothermal system as well as its contribution to the shallow thermal groundwater and freshwater in terms of enthalpy and chemicals require a close monitoring. The phase of unrest occurred since 2010 and culminated with an eruption in 2012, after several years of relative stability, stillmaintains amoderate alert, as required by the high seismicity and SO2 degassing. In October 2013, a sampling campaign has been performed on thermal springs and stream water, located at 2600–5000 m of elevation on the slope of Nevado del Ruiz, analyzed for water chemistry and stable isotopes. Some of these waters are typically steam-heated (low pH and high sulfate content) by the vapour probably separating from a zoned hydrothermal system. By applying a model of steam-heating, based on mass and enthalpy balances, we have estimated themass rate of hydrothermal steam discharging in the different springs. The composition of the hottest thermal spring (Botero Londono) is probably representative of a marginal part of the hydrothermal system, having a temperature of 250 °C and low salinity (Cl ~1500 mg/l), which suggest, along with the retrieved isotope composition, a chiefly meteoric origin. The vapour discharged at the steam vent “Nereidas” (3600 m asl) is hypothesized to be separated from a high temperature hydrothermal system. Based on its composition and on literature data on fluid inclusions, we have retrieved the P-T-X conditions of the deep hydrothermal system, aswell as its pH and fO2. The vapour feeding Nereidas would separate from a biphasic hydrothermal system characterized by the following parameters: t= 315 °C, P= 15 MPa, NaCl = 10 wt%, CO2=5 wt%, and similar proportion between liquid and vapour. Considering also the equilibria involving S-bearing gases and HCl, pH would approach the value of 1.5 while fO2 would correspond to the FeO-Fe2O3 buffer. Chlorine content is estimated at 10,300mg/l. Changes in the magmatic input into the hydrothermal system couldmodify its degree of vapourization and/or P-T-X conditions, thus inducing corresponding variations in vapour discharges and thermal waters. These findings, paralleled by contemporary measurements of water flow rates, could give significant clues on risk evaluation.

Description: Published

Description: 40-53

Description: 2V. Struttura e sistema di alimentazione dei vulcani

Description: JCR Journal

Description: This study focuses on the interaction among deep volcanic/hydrothermal gases, groundwater and soil gases at Vulcano Island (Aeolian Archipelago, Italy). The chemical-physical parameters of the groundwater, the total dissolved inorganic carbon (TDIC) and the isotopic composition of the CO2 dissolved in groundwater are reported and discussed. Furthermore, a comparison between soil gases and groundwater indicates that groundwater and soil gases show the same qualitative information, giving a good overall picture of the main degassing zones of a volcanic system, whereas the soil gas discharge provides an evaluation of the mass released by the deep feeding system. This approach can be a useful tool both to characterize mixing and/or interaction processes among different sources and for a monitoring of degassing activity of a volcanic system.

Description: Published

Description: 116-119

Description: 2V. Struttura e sistema di alimentazione dei vulcani

Description: 4V. Dinamica dei processi pre-eruttivi

Description: N/A or not JCR

Description: Comprehensive hydrogeochemical studies have been conducted in the Campi Flegrei volcanic aquifer since late 20th century due to the volcanic unrest. In the last decade, groundwater samples were grouped based on the dominant anion species (i.e. bicarbonate, sulfate and chloride) to explain the general hydrogeochemical processes. In this article, 44 groundwater samples are collected from Campi Flegrei aquifer to geochemically and spatially capture the main characteristics of the groundwater body. The hierarchical clustering algorithm is then performed on proportion of bicarbonate, sulfate and chloride, and the optimum number of clusters are determined regarding the results of deep hydrogeochemical investigations published in the past. The collected samples are categorized in the following groups: (1) bicarbonate-rich groundwater; (2) chlorine-rich groundwater; (3) sulfate-rich groundwater; and (4) mixed groundwater. The first group (As = 158.2 ± 169 μg/l, electric conductivity = 1,732.1 ± 1,086 μS/cm and temperature = 25.6 ± 8 ◦C) is mainly derived from poor arsenic meteoric water, but there is significant thermal/seawater contribution in the second one (As = 1,457.8 ± 2,210 μg/l, electric conductivity = 20,118.3 ± 11,139 μS/cm and temperature = 37.1 ± 20 ◦C). Interaction of the bicarbonate-rich groundwater and hydrothermal vapors gives rise to the sulfate-rich groundwater (As = 847.2 ± 679 μg/l, electric conductivity = 3,940.0 ± 540 μS/cm and temperature = 82.8 ± 3 ◦C) around Solfatara volcano. The mixed groundwater (As = 451.4 ± 388 μg/l, electric conductivity = 4,482.9 ± 4,027 μS/cm and temperature = 37.1 ± 16 ◦C) is observed where the three main groundwater groups undergo a mixing process, depending on the hydrogeology of the volcanic aquifer. Contrary to the bicarbonate- and sulfate-rich groundwater, the chlorine-rich and mixed groundwater generally occurs at low piezometric levels (approximately 〈1 m above sea level) near the coastline. The hierarchical cluster analysis provides more information about the volcanic aquifer, particularly when compositional data analysis is applied to study hydrogeochemistry of the homogeneous groundwater groups and to uncover the relationships between variables. Addressing compositional nature of data is recommended in the future studies for developing new tools that help deeper understanding of groundwater evolution in volcanic aquifers and identifying promising precursors of volcanic eruption.

Description: Published

Description: 106922

Description: 4V. Processi pre-eruttivi

Description: 2IT. Laboratori analitici e sperimentali

Description: JCR Journal

Description: Here we discussed the results of the first geochemical investigation of the fluids (groundwater and the associated gases) emerging in the southwest of Yazd Province. We carried out two surveys, one in July 2019 and the second in September 2019s, in the region of the Gariz aquifer (central Iran).Wefocused our attention to 1) the chemistry of thewater (major and minor constituents coupled to the stable isotopes of oxygen and hydrogen), 2) the chemical composition of dissolved gases in water together with 3) the isotopic composition of Helium (3He/4He) and 4) the dissolved carbon in water (δ13CTDIC). Hydrogen and oxygen isotope values of groundwater display a fairly narrow range and indicate that the waters are of meteoric origin. On the base of the major ions chemistry, the bulk of the water samples are classified as Ca-HCO3, Ca\\Cl and Na\\Cl types. The groundwater chemistry is mainly influenced by the interaction with CO2-rich fluids, leakage of chlorinated saline water into the alluvial aquifer, and silicate dissolution. High dissolved carbon contents, mainly as bicarbonate ion, reflect the noticeable interaction of the groundwater with CO2-rich fluids. CO2 is the dominant gaseous component in most samples and its amount is always greater with respect to a water in equilibrium with the atmosphere (Air Saturated Water, ASW). Such excess of CO2 contents (more than 730 cc/l STP) dissolved in groundwater also supports the presence of a deep source of CO2-rich gas. The computed δ13C(CO2) in equilibriumwith the groundwater highlight a mixing in different proportion between an inorganic deep sourced CO2 (13C-enriched) and organic CO2 (13C-depleted). We also used the helium isotopes as a tools to figure out the origin of helium in the aquifer (air vs. mantle, and crust). The collected samples show a contribution of mantle-derived He in the Gariz aquifer up to (~45%) and the crust suggesting that at regional scale the tectonic discontinuities had a connectionwith the mantle or magmatic intrusions migrated through the crust transporting mantle volatiles to shallowcrustal layers. However, we cannot infer the timing of this possible magmatism at depth in the complex tectonic evolution of the area.

Description: Ministry of Science, Research and Technology of Iran

Description: Published

Description: 107324

Description: 1TR. Georisorse

Description: JCR Journal

Description: Archaeological sites are extremely vulnerable to the impacts of weather-related events, which may lead to irreparable damages to cultural heritage. Here an assessment of the debris-flow hazard for the UNESCO site of Roman Villa del Casale (Italy) is carried out, through a combination of historical analyses, field surveys, geomorphological and hydrological investigations and two-dimensional hydraulic numerical modelling, all performed at river catchment scale. Historical analyses reveal that the site has been hit by several landslides in the far and recent past. This is presently confirmed by the high level of exposure to the impact of rain-triggered debris-flow events, due to the position of the Villa at a closure section of the related river basin and to the hydro- geomorphological characteristics of the basin itself. By applying the proposed approach, a scenario analysis is carried out. Results allow one to highlight the dynamics of the impact of debris flows, thanks to space and time- dependent maps about deposition areas, water depth and speed values, and to identify the most vulnerable archaeological elements within the study site. The numerical simulations are also used to test the efficiency of the existing hydraulic defense systems and to support the implementation of an early warning system for the site protection. Here, we also synthetize the design of the architecture of the wireless monitoring network, the sensor technology adopted to develop an effective real time environmental monitoring system and management plat-form, to construct a Wireless Sensor Network (WSN) - early warning and reporting system, which can be applied as a prevention measure.

Description: Published

Description: 102509

Description: 7A. Geofisica per il monitoraggio ambientale

Description: JCR Journal

Description: The needs of society and the emerging blue economy require access and integration of data and information for the construction of dedicated products. A “transparent and accessible ocean” is one of the key objectives of the Ocean Decade 2021–30. In this context, marine infrastructures become significant components of a global knowledge environment, enabling environmental assessment and providing the necessary data for scientifically valid actions to protect and restore ocean health, to use marine resources in a sustainable way. The data is collected, analyzed, organized, and used by people and their good use/reuse can be obtained with social practices, technological and physical agreements aimed at facilitating collaborative knowledge, decision-making, inference. The vision is a digital ocean data ecosystem made up of multiple, interoperable, and scalable components. The huge amount of data and the resulting products can drive the development of new knowledge as well as new applications and services. Predictive capabilities that derive from the digital ecosystem enable the implementation of services for real-time decision-making, multihazard warning systems, and advance marine space planning. The chapter develops following the progressive complexity and information content of products deriving from oceanic data: data cycle and data collections, data products, oceanic reanalysis. The chapter discusses the new challenges of data products and the complexity of deriving them.

Description: Published

Description: 197-280

Description: 4A. Oceanografia e clima

Description: Graciosa Island is located in the Azores Archipelago, along the so-called Terceira Rift, NE boundary of the Azores Plateau. From the hydrochemical point of view, two types of Na-Cl groundwater systems were identified: a cold aquifer system emerging at springs and exploited through boreholes for public water supply with different degrees of mineralization, and a hydrothermal system with issuing temperatures around 45 ºC. Geothermometers applied to the thermal waters point to deep temperature around 167 ºC and to immature waters, not reaching complete equilibrium with the reservoir rock. The isotopic composition and geochemistry of the thermal waters indicate mixture groundwater - seawater in different percentages and ion-exchange mechanisms that will be able to: i) increase groundwater salinity, ii) strongly change the isotopic composition to more enriched values, with different degrees of mixing.

Description: Published

Description: 630-633

Description: 2V. Struttura e sistema di alimentazione dei vulcani

Description: N/A or not JCR

Description: Carbon captured and stored in sediments and soils from vegetated tidal wetlands (mangroves, saltmarshes, freshwater and brackish marshes), where the rates of organic carbon accumulation (OC) from multiple sources is high, constitutes an active fraction of the global carbon sink (Wang et al., 2021). However, a global inventory of this coastal ‘blue carbon’ remains a challenge, as observations of accumulation rates and stock in vegetated tidal wetlands are labor intensive, expensive, scarce, and unevenly distributed, with few sediment records even for relatively well-studied temperate areas in the Northern Hemisphere (Beaumont et al., 2014). Recent reviews (Duarte et al., 2005, Wilkinson et al., 2018) report a mean carbon accumulation rate of 151 g C m yr for saltmarshes (maximum 1720 g C m yr), 41.4 g C m yr for lagoons (maximum 340 g C m yr), and 62.9 g C m yr for coastal wetlands (maximum 335.8 g C m yr) exceeding the mean burial rate of estuaries and continental shelves (17–45 g C m yr ). The accumulation of ‘blue carbon’ stored in soil and sediments within tidal wetlands, is sensitive to rapidly changing climate factors (e.g. temperature, rainfall, sea level rise, and inundation frequency), and non-climatic anthropogenic drivers (e.g. subsidence from groundwater extraction, reduction of sediment supply due to river damming, and land use change) (Pendleton et al., 2012, Macreadie et al., 2013, Arriola, 2017, Kelleway et al., 2017, Simpson et al., 2017, Ewers Lewis et al., 2018, Ruiz-Fernández et al., 2018, Cuellar-martinez et al., 2019, Macreadie and Saintilan, 2019, Negandhi et al., 2019, Rogers et al., 2019). Fast rates of relative sea level rise (RSLR) and low sediment supply are the main drivers of vertical drowning in tidal wetlands (Mariotti and Carr, 2014, Fagherazzi et al., 2020). A global review suggests that between 60 and 91% of saltmarshes will be drawing under the IPPC predicted rates of sea-level rise (Crosby et al., 2016). Carbon stable isotopic composition ( C) and C/N analysis have been used as tracers to distinguish between OC derived from autochthonous C3 and C4 saltmarsh vascular vegetation (i.e. coastal blue carbon; C 12‰ to −30‰, C/N 5.80 to 41.10; Khan et al., 2015b), and allochthonous sources including fluvial and marine particulate organic matter (POM) derived from freshwater or marine phytoplankton (C 12‰ to −30‰, C/N 5 to 9; Lamb et al., 2006), as well as past sea level indicators in coastal vegetated​ habitats in North West Europe (Wilson, 2017). Data on the spatial and historical changes of OC sources and accumulation coupled with long-term time series of climatic factors are limited for vegetated tidal wetlands in the Mediterranean, which make it hard to assess the response of OC accumulation to relative sea-level rise (RSLR) in this region. Sea level observations from satellite altimetry showed an increase in absolute sea level of 2.6 ± 0.28 mm yr across the Mediterranean Sea during the period 1993–2015, and low-lying coastal areas will be prone to marine flooding according to projections for the 21st century (Moatti and Thiébault, 2016). To better understand the spatial and temporal changes in OC accumulation and sources and assess the influence of SST and RSLR, we measured the stable isotopic composition ( C) and accretion rates in sediment records, applied the MixSIAR model to estimate the OC sources, and analyzed Sea Surface Temperature (SST) and Sea Level (SL) climatic data sets in two different tidal wetland habitats: (i) an impacted habitat affected by strong landscape and anthropogenic alterations, and (ii) an undegraded saltmarsh habitat, within a coastal lagoon (Pialassa Baiona) located in the northwestern Adriatic Sea (Mediterranean Sea).

Description: Published

Description: 102439

Description: 4A. Oceanografia e clima

Description: JCR Journal

Description: The carbon isotopic composition of dissolved C-bearing species is a powerful tool to discriminate the origin of carbon in thermal waters from volcanic and hydrothermal systems. However, the δ13C values of dissolved CO2 and TDIC (Total Dissolved Inorganic Carbon) are often different with respect to the isotopic signature that characterizes the potential carbon primary sources, i.e. deep hydrothermal reservoirs, magmatic gases and organic activity. The most commonly invoked explanation for such isotopic values is related to mixing processes between deep and shallow end-members. Nevertheless, experimental and empirical investigations demonstrated that isotopic fractionation due to secondary processes acting on the uprising fluids from the hydrothermal reservoirs is able to reproduce the measured isotopic values. In this paper,we investigated the chemistry of thermalwaters, collected at Campi Flegrei and Vulcano Island (southern Italy),whose origin is related to interaction processesamongmagmatic gases, meteoric water, seawater and hosting rocks. A special focus was dedicated to the δ13C values of dissolved CO2 (δ13CCO2(aq)) and total dissolved inorganic carbon (δ13CTDIC). The δ13CCO2(aq) and δ13CTDIC values in the water samples fromboth these systems ranged from(i) those measured in fumarolic gases, likely directly related to the deep hydrothermal-magmatic reservoir, and (ii) those typically characterizing biogenic CO2, i.e. produced by microbially-driven degradation of organic matter. A simple mixingmodel of the two end-members, apparently explaining these intermediate carbon isotopic values, contrastswith the chemical composition of the dissolved gases. On the contrary, isotopic fractionation due to secondary processes, such as calcite precipitation, affecting hydrothermal fluids during their underground circulation, seems to exhaustively justify both the chemical and isotopic data. If not recognized, these processes, which frequently occur in volcanic and hydrothermal systems, may lead to an erroneous interpretation of the carbon source, causing an underestimation of the contribution of the hydrothermal/magmatic fluids to the dissolved carbon species. These results pose extreme caution in the interpretation of intermediate δ13CCO2(aq) and δ13CTDIC values for the assessment of the carbon budget of hydrothermal- volcanic systems.

Description: Published

Description: 46–57

Description: 2V. Struttura e sistema di alimentazione dei vulcani

Description: 4V. Dinamica dei processi pre-eruttivi

Description: JCR Journal