ALBERT

Description: Deeply-sourced fluids are released in volcanically and tectonically active regions through conduits such as fumaroles, natural springs, and permeable soils. The origin and transport of the fluids in volcanic and tectonic systems are a key research theme in Earth Sciences, which is of particular importance for geo-hazard mitigation and resource exploration. This Research Topic aims to present recent advances in fluid geochemistry and its application in volcanically and tectonically active regions. Under this context, 10 papers covering a series of research themes in fluid geochemistry were published in this Research Topic, as briefly summarized below. People living close to active fault zones are threatened by earthquake hazard and therefore monitoring the status of active faults is important to mitigate the damage caused by future earthquakes. Caracausi et al. reported data from a novel infrastructure designed for multidisciplinary and continuous monitoring of the Alto Tiberina fault, Italy. Monitoring results (including seismic, geodetic, and geochemical data) from The Alto Tiberina Near Fault Observatory (TABOO-NFO) would shed new light on earthquake prediction studies in other countries. Fidani et al. conducted a comprehensive statistical analysis of CO2 time series registered at the Gallicano test site, Italy, and identified the correlations between low- magnitude earthquakes and CO2 anomalies in spring waters. Li et al. studied the spatial variations in soil Rn and CO2 emissions in the Wuzhong-Lingwu region, NW China, as well as the possible controlling factors of earthquakes, stress state, and deep-to-shallow crustal structures. Their findings offer new insight into combining geochemical characteristics of soil gas and seismological methods to estimate regional seismic hazards. Under the context of continuous collision between Indian and Asian continents, the Tibetan Plateau and its surrounding regions have drawn increasing concern from the Earth science community because of intensive and frequent earthquake events. Liu et al. reported the first estimates of diffuse soil CO2 flux (~1.2 Mt yr–1) for the Anninghe-Zemuhe fault in the Southeast Tibetan Plateau and found close relationships between spatial variations in soil CO2 fluxes and that of regional seismic activity. Based on the geochemistry of hot spring waters, Liu et al. explored the controls of the Jinshajiang fault zone (SW China) on hydrothermal fluid circulation, water-rock interaction, and earthquakes, which highlighted the role of hot spring water discharging from fracture zones in receiving the hydrological information on seismic activity. Also published in this Research Topic, Liu et al. presented an example of post-earthquake hydrological changes based on carbon isotope data of spring waters collected after the 2021 Mw 7.4 Maduo earthquake in eastern Tibetan Plateau. They quantitatively identified enhanced mobilization of the shallow soil organic carbon following the 2021 Maduo earthquake and suggested that earthquakes could disturb the circulation of subsurface fluids and their interaction with the country rocks and sediments on short timescales. Wang et al. investigated origin and circulation of geothermal waters in the Karakoram strike-slip fault zone in western Tibet. Their results show that geothermal water is correlated with the epicenter and focal depth of earthquakes, especially for high-temperature spring water with deeper circulation and extremely high Li, B, Fe, and As concentrations. Three papers in this Research Topic focus on the degassing of historically active volcanoes. Gherardi et al. investigated helium isotopes on gas extracted by crushing from melt and fluid inclusions in minerals from Plinian and inter-Plinian tephra and lavas of Vesuvius, Italy. Their results show that i) 3He/4He values are buffered within an extended, deep-seated reservoir at about 10 km filled with magma rising from the mantle, and ii) magma ponding at crustal depth could be considered a key mechanism that might have the potential to homogenize the helium isotope signal. Located in the hinterland of Northeast Asia, the active Arxan volcanic field remains less studied for the characteristics of its present-day volcanic degassing. Pan et al. focused on diffuse soil CO2 fluxes and found that annual CO2 emission flux from the volcanic field to the atmosphere is ~0.63 × 105 t and is comparable to that of the Iwojima volcano in Japan. This is the first flux estimate for soil CO2 emissions of the Arxan volcanic field. Cui et al. presented a geochemical study on the hot spring water and gases from the Arxan volcanic field. They identified ~3%–23% mantle helium inputs and thus heat supply in the hydrothermal fluids, suggesting that the residual mantle-derived melts beneath the Arxan volcanic field are still releasing fluids/volatiles and heating the overlying hydrothermal systems.

Description: Published

Description: 1304789

Description: OST5 Verso un nuovo Monitoraggio

Description: JCR Journal

Description: The Campanian Volcanic Zone (CVZ) comprises multiple active volcanoes and includes the highly productive Campi Flegrei and Ischia caldera systems. These caldera volcanoes have produced probably the largest eruptions in Europe in the past 200 ka, such as the Monte Epomeo Green Tuff (MEGT; Ischia) at ca. 56 ka and the Campanian Ignimbrite (CI; Campi Flegrei) at ca. 40 ka, which form widespread isochrons across the Mediterranean region. These closely-spaced volcanic centres erupt phonolitic to trachytic glass compositions that are similar, and thus it can be challenging to correlate tephra deposits to specific volcanic sources. Here we present a detailed tephrostratigraphy for pre-CI eruption activity using the units preserved within a sequence at the coastal Acquamorta outcrop, on the western side of the CI caldera rim. Both the MEGT and CI units are present in the section, and they bracket twelve eruption units that were logged and sampled. New major and trace element glass chemistry data have been acquired for these Acquamorta tephra deposits. Three eruption deposits from Ischia and nine from Campi Flegrei are identified, which helps constrain the tempo of volcanic activity of these centres between the large caldera-forming eruptions. The three Ischia tephra deposits between the MEGT and the CI are indistinguishable based on both major and trace element glass chemistry and cannot be correlated to a specific or known eruption in this interval, such as the Schiappone tephra. The compositional variations between the Campi Flegrei eruptions reveal temporal shifts in the composition of the tephra deposits that reflect changes in the magmatic system prior to the CI eruption. These deposits indicate that there were at least nine eruptions at Campi Flegrei within 16 ka of the enormous CI eruption, and suggest that there was no significant period of repose before the caldera generating eruption.

Description: Published

Description: 107915

Description: OSV2: Complessità dei processi vulcanici: approcci multidisciplinari e multiparametrici

Description: JCR Journal

Description: This reprint "The November 23rd, 1980 Irpinia-Lucania, Southern Italy Earthquake: Insights and Reviews 40 Years Later” presents a collection of 13 scientific contributions proposed by 44 researchers with different expertise and multidisciplinary approach highlighting the most important aspects of the Irpinia-Lucania earthquake (Ms 6.9, Io X MCS) from a seismological and geological point of view, without neglecting the reconstruction of cultural heritage, the resilience of the population, and the socioeconomic development of the internal areas of the Southern Apennines after the earthquake. The 1980 earthquake struck Irpinia-Lucania region (Southern Italy) and it is remembered in Italy not only for being the strongest earthquake recorded in the last 100 years causing devastation of entire regions and severe loss of human life, but also for the destruction of the cultural heritage in the epicentral area. This volume, far from being exhaustive, nevertheless wants to be an important point of reference for the new generations of researchers who will have both a historical and multidisciplinary approach to the knowledge of this earthquake.

Description: Published

Description: Active volcanoes are a continuous threat for several regions worldwide and cause socio-economic and environmental issues, including the Virunga Volcanic Province (D.R. Congo). There, more than 2 million people are permanently exposed to the hazards of the most active volcanoes in Africa: Nyiragongo and Nyamulagira. However, there is a clear lack of information regarding the impacts of these hazards and how they may be affected by social vulnerability. In this study, a household survey based on semi-structural interviews was performed for rural communities in Virunga. This research aims to (i) investigate the impacts of volcanic hazards on rural communities facing distinct levels of social vulnerability, (ii) understand the adaptive strategies developed by these communities to address these impacts, and finally (iii) identify the main grievances with respect to volcanic hazards raised by these rural communities. The most vulnerable households are those directly affected by volcano-tectonic hazards such as lava flows, mazukus, volcanic gases, ash fallout, and seismic activity. Indirect dangers related to water and food contamination by volcanic emissions are also stronger for the most vulnerable households. Respondents reported that most edible plants and waters are strongly affected by direct volcanic emissions. Drinking waters, which come from traditional drainage, rainfall, and streams, are generally not suitable for human consumption in the study area. Community suggestions for addressing issues related to volcanic-tectonic hazards include efforts to improve water and food quality, enhancement of the sanitary system, timely information on the volcanic activity, volcano monitoring, and capacity building for volcanologists.

Description: Published

Description: 103566

Description: JCR Journal

Description: Services from the Continuously Operating Reference Stations (CORS) of the Global Navigation Satellite System (GNSS) provide data and insights to a range of research areas such as physical sciences, engineering, earth and planetary sciences, computer science, and environmental science. Even though these fields are varied, they are all linked through the GNSS operational application. GNSS CORS have historically been deployed for three-dimensional positioning but also for the establishment of local and global reference systems and the measurement of ionospheric and tropospheric errors. In addition to these studies, CORS is uncovering new, emerging scientific applications. These include real-time monitoring of land subsidence via network real-time kinematics (NRTK) or precise point positioning (PPP), structural health monitoring (SHM), earthquake and volcanology monitoring, GNSS reflectometry (GNSS-R) for mapping soil moisture content, precision farming with affordable receivers, and zenith total delay to aid hydrology and meteorology. The flexibility of CORS infrastructure and services has paved the way for new research areas. The aim of this study is to present a curated selection of scientific papers on prevalent topics such as network monitoring, reference frames, and structure monitoring (like dams), along with an evaluation of CORS performance. Concurrently, it reports on the scientific endeavours undertaken by the Geomatics Research Group at the University of Palermo in the realm of GNSS CORS over the past 15 years.

Description: Published

Description: 5343

Description: JCR Journal

Description: Campi Flegrei (CF) is an active and densely populated caldera in Southern Italy, which has manifested signs of significant unrest in the last 50 years. Due to the high volcanic risk, monitoring networks of the most sensitive unrest indicators have been implemented and improved over time. Precious database constituted by geophysical and geochemical data allowed the study of the caldera unrest phases. In this paper we retrace the caldera history in the time span 2000-2020 by analyzing displacement, seismicity and geochemical time series in a unified framework. To this end, Principal Component Analysis (PCA) was firstly applied only on geochemical data because of their compositional nature. The retrieved first three components were successively analyzed via PCA together with the geophysical and thermodynamical variables. Our results suggest that three independent processes relay on geochemical observations: a heating/pressurizing of the hydrothermal system, a process related to magmatic fluids injection at the hydrothermal system roots, and third process probably connected with a deeper magmatic dynamic. The actual volcano alert state seems mainly linked to the variation of the hydrothermal system activity. Our approach made it possible to explore the interrelation among observations of different nature highlighting the importance of the relative driving processes over time.

Description: Published

Description: 18445

Description: JCR Journal

Description: On December 26, 2018 (2:19 UTC), during a volcanic eruption on the Mt. Etna eastern flank (Sicily, southern Italy), the largest instrumental earthquake ever recorded in the volcano ruptured the Fiandaca Fault, with epicenter between Fleri and Pennisi villages (hypocenter at ca. 300 m a. s. l., Mw 4.9). This was the mainshock of an earthquake swarm and it was accompanied by widespread surface faulting and extensive damage along a narrow belt near the fault trace. Few hours after the mainshock, an episodic aseismic creep event occurred along the Aci Platani Fault, a SE extension of the Fiandaca Fault, which caused several damages in the Aci Platani village. We surveyed and mapped the coseismic and aseismic ground ruptures, and collected structural data on their geometry, displacement, and fault zone fabric. We compared the mapped surface ruptures with topography, lithology, and morphology of the buried top of the sedimentary basement. We conclude that the geometry of the volcanic pile influenced the surface expression of faulting during the December 26, 2018 event. The top surface of the marly clay basement should be considered as a detachment surface for shallow sliding blocks. The earthquake occurred on top of a depression of the sedimentary basement forcing the sliding eastward, causing at surface the re-arrangement of the fault strand pattern and deformation style, switching from shear faulting to a tensile failure. The Fleri earthquake therefore provides an unprecedented dataset for 1) understanding active faulting in the European largest onshore volcano, 2) modeling its complex dynamics, and 3) contributing to a more refined surface faulting hazard assessment at Mt. Etna. Results from this investigation might be useful for characterizing capable faulting in similar volcano-tectonic settings worldwide.

Description: Published

Description: 25-41

Description: JCR Journal

Description: As part of the second phase of the Regional Carbon Cycle Assessment and Processes project (RECCAP2), we present an assessment of the carbon cycle of the Atlantic Ocean, including the Mediterranean Sea, between 1985 and 2018 using global ocean biogeochemical models (GOBMs) and estimates based on surface ocean carbon dioxide (CO2) partial pressure (pCO2 products) and ocean interior dissolved inorganic carbon observations. Estimates of the basin-wide long-term mean net annual CO2 uptake based on GOBMs and pCO2 products are in reasonable agreement (−0.47 ± 0.15 PgC yr−1 and −0.36 ± 0.06 PgC yr−1, respectively), with the higher uptake in the GOBM-based estimates likely being a consequence of a deficit in the representation of natural outgassing of land derived carbon. In the GOBMs, the CO2 uptake increases with time at rates close to what one would expect from the atmospheric CO2 increase, but pCO2 products estimate a rate twice as fast. The largest disagreement in the CO2 flux between GOBMs and pCO2 products is found north of 50°N, coinciding with the largest disagreement in the seasonal cycle and interannual variability. The mean accumulation rate of anthropogenic CO2 (Cant) over 1994–2007 in the Atlantic Ocean is 0.52 ± 0.11 PgC yr−1 according to the GOBMs, 28% ± 20% lower than that derived from observations. Around 70% of this Cant is taken up from the atmosphere, while the remainder is imported from the Southern Ocean through lateral transport.

Description: To investigate the long-term stability of deep rocks, a three-dimensional (3D) time-dependent model that accounts for excavation-induced damage and complex stress state is developed. This model com- prises three main components: a 3D viscoplastic isotropic constitutive relation that considers excavation damage and complex stress state, a quantitative relationship between critical irreversible deformation and complex stress state, and evolution characteristics of strength parameters. The proposed model is implemented in a self-developed numerical code, i.e. CASRock. The reliability of the model is validated through experiments. It is indicated that the time-dependent fracturing potential index (xTFPI) at a given time during the attenuation creep stage shows a negative correlation with the extent of excavation- induced damage. The time-dependent fracturing process of rock demonstrates a distinct interval effect of the intermediate principal stress, thereby highlighting the 3D stress-dependent characteristic of the model. Finally, the influence of excavation-induced damage and intermediate principal stress on the time-dependent fracturing characteristics of the surrounding rocks around the tunnel is discussed. Ó 2024 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/).

Description: The Lindero deposit is located in the Puna plateau, northwest Argentina, at the southern end of the Central Volcanic Zone of the Central Andes. The high-K calc-alkaline dioritic composition of the subvolcanic intrusions, the shallow emplacement depth (〈 1.5 km), and the gold-rich and copper-depleted mineralization style suggest that the Lindero deposit is a porphyry gold deposit. Porphyry gold deposits are scarce worldwide and the factors controlling their formation are still poorly known. Here we present a detailed study of fluid inclusions in order to characterize the mineralizing fluids that precipitated the Au mineralization at Lindero. Different types of fluid inclusions in quartz veins (A-type and banded quartz), which are associated with the K-silicate alteration, were analyzed using Raman spectroscopy, microthermometry, and LA-ICP-MS (laser ablation inductively coupled plasma mass spectrometry). Four inclusion types can be recognized in quartz veins: (i) Salt melt inclusions, which are characterized by a dense packing of daughter minerals (mainly Fe-chloride, sylvite, halite, anhydrite, and hematite), by a distorted vapor bubble, and by the lack of liquid phase; (ii) Halite-bearing inclusions which contain liquid, vapor, and halite; (iii) Two-phase aqueous inclusions that contain liquid and vapor; (iv) Vapor-rich inclusions containing only vapor. The inclusion types are related to different stages of hydrothermal evolution. Stage 1 is the main mineralization stage, characterized by vapor-rich inclusions coexisting with salt melt inclusions. Salt melt inclusions commonly show total homogenization temperature (ThL) 〉 1000 °C. This Na-K-Fe-Cl-rich highly saline brine (~ 90 wt% NaCl eq.) was of magmatic origin and responsible for the Au mineralization. Two later stages involving cooler fluids (ThL 〈 300 °C) and gradually lower salinities (from 36.1 to 0.2 wt% NaCl eq.) trapped by halite-bearing and two-phase aqueous inclusions during stages 2 and 3, respectively, correspond to a late magmatic-hydrothermal system, that is probably related to a deep supercritical fluid exsolution. Salt melt inclusions represent the most likely parental fluid of K-silicate alteration and associated Au mineralization at Lindero. This uncommon type of fluid must have played an important role in Au transport and precipitation in shallow porphyry gold deposits.