ALBERT

Description: The late Miocene Monte Capanne and Porto Azzurro plutons are investigated by means of coupled U-Pb zircon and 40Ar/39Ar white mica dating to test the occurrence of long-lived magmatic systems in the upper crust. Zircon crystallized for 〉 1 Myr in both plutonic systems, with supersolidus conditions overlapping for ~220 kyr indicating previously unrecognized co-existence of the two reservoirs. The development of the Porto Azzurro high T-aureole is post-dated by continuous igneous zircon crystallization until ~ 6.0 Ma. By linking crystallization to post-emplacement cooling of late-stage pulses in both western and eastern Elba we constrain long-lived sizeable reservoirs (possibly the same reservoir) in the Tyrrhenian upper crust between ~8 and 6 Ma.

Description: In press

Description: OST1 Alla ricerca dei Motori Geodinamici

Description: JCR Journal

Description: In this body of work, we showcase a historic virtual geotrail on the eastern flank of the iconic Mt. Etna volcano (Italy), along a series of outstanding geological sites and features subsequent to an important eruption that took place in 1928. A geohistoric account of such a major eruption, is of great interest, since it is the only event since 1669 to have caused the destruction of a town (Mascali) in the Etna region. Volcanologists, educators, the lay public, tourists and volcano explorers can now access a series of “virtual geostops” belonging to this virtual geotrail, such that “visitors” can virtually fly above these sites by scanning a QR code on the printed or electronic version of the present manuscript, as well as on the poster provided as additional material for this manuscript. The virtual geostops that comprise the virtual geotrail were developed using the structure-frommotion (SfM) photogrammetry technique from images captured by using unmanned aerial vehicles (UAVs). The main result of our work is the virtual geotrail, subdivided in two parts and composed of eight geostops, each showing outstanding examples of geological features resulting from volcanic phenomena that took place also during 1979. Our approach is designed to support classical field trips, and it can undoubtedly become complementary to traditional field teaching in earth sciences, both now and in the future.

Description: Published

Description: 377

Description: 1V. Storia eruttiva

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

Description: 2TM. Divulgazione Scientifica

Description: JCR Journal

Description: Stromboli is an open-conduit active volcano located in the southern Tyrrhenian Sea and is the easternmost island of the Aeolian Archipelago. It is known as “the lighthouse of the Mediterranean” for its continuous and mild Strombolian-type explosive activity, occurring at the summit craters. Sometimes the volcano undergoes more intense explosions, called “major explosions” if they affect just the summit above 500 m a.s.l. or “paroxysms” if the whole island is threatened. Effusive eruptions are less frequent, normally occurring every 3–5 years, and may be accompanied or preceded by landslides, crater collapses and tsunamis. Given the small size of the island (maximum diameter of 5 km, NE–SW) and the consequent proximity of the inhabited areas to the active craters (maximum distance 2.5 km), it is of paramount importance to use all available information to forecast the volcano’s eruptive activity. The availability of a detailed record of the volcano’s eruptive activity spanning some centuries has prompted evaluations on its possible short-term evolution. The aim of this paper is to present some statistical insights on the eruptive activity at Stromboli using a catalogue dating back to 1879 and reviewed for the events during the last two decades. Our results confirm the recent trend of a significant increase in major explosions, small lava flows and summit crater collapses at the volcano, and might help monitoring research institutions and stakeholders to evaluate volcanic hazards from eruptive activity at this and possibly other open-vent active basaltic volcanoes.

Description: This research was funded by Project FIRST—ForecastIng eRuptive activity at Stromboli volcano: timing, eruptive style, size, intensity, and duration, INGV–Progetto Strategico Dipartimento Vulcani 2019 (Delibera n. 144/2020; Scientific Responsibility: S.C.).

Description: Published

Description: 4822

Description: 1V. Storia eruttiva

Description: JCR Journal

Description: In the last two decades, the rapid growth in continuous Global Navigation Satellite Systems (GNSS) networks and improvements in Interferometric Synthetic Aperture Radar (InSAR) imaging allowed the acquisition of continuous and spatially extensive datasets over large regions of Earth, significantly increasing the range of geoscience applications. In addition, the promising results obtained by the scientific community and the free availability of data, which permitted drastic cost reductions, have drawn increasing interest from the administrative managing office for the mapping and monitoring of ground deformation issues. This Special Issue aims to provide a general overview of some geoscience applications of GNSS and InSAR techniques which are commonly used to study the surface deformation related to co- and post-seismic deformation, subsurface movements of magma beneath active volcanoes, soil deformation (e.g., natural/anthropic uplift or subsidence), monitoring of landslide, monitoring of industrial settlements, the motion of ice sheets, etc. The GNSS technique provides a set of 3D geodetic observations at a limited number of points on the ground surface. The continuous technological development in GNSS equipment currently allows collecting measurements at higher rates (up to 100 Hz), offering a wide range of new applications for solid and fluid Earth investigations. The InSAR technique provides a spatially dense set of geodetic observations of ground deformation in the viewing geometry of the satellite sensor, and with a temporal sampling limited to the satellite orbital revisit (up to 6 days with the Sentinel constellations). Any deformation of the ground surface can be measured by comparing two radar images of the same area, collected at different times from approximately the same position in space. InSAR processing advancements also allowed multi-temporal analyses, which sensibly improved the investigation of long-term deformation events. GNSS and InSAR measurements can complement each other and are generally combined to infer the 3D surface deformation over a target region. A review of more than 190 studies dealing with InSAR and GNSS combined measurements has been proposed in Del Soldato et al. [1]. The ground deformation measurements coming from both techniques have been combined for different purposes [1], evidencing how their joint use has been readily employed by the scientific community as well as by stakeholders and environmental managers. In turn, the increasing range of applications started to push the development of new approaches aimed at fast and robust combinations of GNSS and InSAR measurements. In such a frame, Xiong et al. [2] proposed an iterative least squares approach for virtual observation (VOILS) based on the maximum a posteriori estimation criterion of Bayesian theorem while Parizzi et al. [3] developed an approach accounting for the spectral properties of the errors of InSAR and GNSS measurements, hence preserving all spatial frequencies of the deformation detected by the two techniques. Both methods have been tested and validated with both synthetic and real data. Achieved results highlighted that both methods led to significant improvement of the spatial accuracy of the combined deformation field, therefore allowing accurate detection of the ongoing deformations. Several studies included in this Special Issue focused on the co-seismic deformation related to moderate to large earthquakes. De Novellis et al. [4] focused on the March 2021 Thessaly seismic sequence (Central Greece) highlighting the activation of unknown distinct blind fault segments in a sort of domino effect within the seismogenic crustal volume. Caporali et al. [5] analyzed the seismic sequence of November 2019 in Albania and inferred a NE-dipping reverse seismogenic fault located at a depth of 8 ± 2 km. Sakkas [6] focused on the 30 October 2020 Mw6.9 Samos Island (Aegean Sea) earthquake and suggested that the earthquake nucleated on a two-segments north-dipping listric fault characterized by a predominant dip-slip component and a minor lateral one. The complex deformation field associated with the April 2016 Kumamoto (Japan) seismic sequence was analyzed by He et al. [7] which modelled a four-segment fault geometry with right-lateral strike-slip kinematics coupled with a minor normal slip component. Valerio et al. [8] focused on the 7 November 2019 Mw5.9 earthquake hitting the East-Azerbaijan region and proposed a shallow NE-SW striking and SE-dipping fault as the seismogenic source. All these studies clearly proved that GNSS and InSAR data analysis and modelling are extremely useful tools in helping to constrain the causative fault of moderate to large earthquakes, especially in the case of blind and unknown faults, therefore providing useful information on the seismic hazard estimation of the investigated areas. Active faults can be also affected by long-term creeping during the interseismic period. Geodetic observations are used to investigate co- and post-seismic deformations as well as transient deformations at least when these phenomena yield deformations high enough to be discriminated from long-term trends. However, there could be the possibility that the whole amount of observed long-term deformation could be partially or totally caused by inelastic processes instead of related to the building of elastic stress preparing the next earthquakes. Cambiotti et al. [9] focused on this topic by proposing a novel inverse method aimed at the discrimination of regional deformation and of long-term fault creep by inverting available GNSS measurements. Sparacino et al. [10] performed a seismic and geodetic moment-rates comparison for the western Mediterranean to identify that regions where the total deformation-rate budget is entirely released by crustal seismicity, and the ones where the excess deformation-rate can be released either in aseismic slip across active faults or through large future earthquakes. Achieved results by both studies proven that the geodetic measurements represent an essential part of the seismic-hazard analysis on highly deforming regions. Other studies included in this Special Issue focused on the surface deformation related to the migration of fluids along the magmatic system of active volcanoes. Galvani et al. [11] analyzed twenty years of GNSS and levelling measurements collected on Ischia Island (Italy) and found a deflating source located at a depth of 4 km below the southern flank of Mt. Epomeo. Battaglia et al. [12] studied the subsidence of Dallol volcano (Erta Ale ridge of Afar, Ethiopia) and inferred a deflating source located beneath the volcano edifice at a depth ranging in the 0.5–1.5 km interval and characterized by a volume decrease between −0.63 and −0.26 × 106 km3/year. Boixart et al. [13] focused on the Sabancaya volcano (southern Perú), detecting an active deep source of deformation located between the Sabancaya and Hualca volcanoes with a volume change rate of 26 × 106–46 × 106 m3/yr. These studies evidenced that GNSS and InSAR techniques can detect and track with high detail the spatial and temporal evolution of the magmatic system during a volcanic crisis. Both techniques are essential tools for the continuous monitoring of active volcanoes as well as to understand magmatism, refine volcano models, and mitigate volcanic hazards. Another topic addressed in this Special Issue is that of land subsidence which can occur for both natural and anthropic causes. Land subsidence represents a relevant issue that might affect highly developed urban and industrialized areas. Cando Jácome et al. [14] focused on the land subsidence due to the underground mining which is causing the collapse of many buildings in the urban area of Zaruma in Ecuador. The authors proposed a forecasting methodology for the continuous monitoring of the long-term soil subsidence in target areas, largely improving the traditional detection performed with total stations and geodetic marks. Mohamadi et al. [15] designed a PS-InSAR-based workflow on the detection of unusual vertical surface motions in urban areas in order to create temporal vulnerability maps for building collapse monitoring. Both studies highlight that the development of methodologies for the continuous monitoring of the land subsidence is strictly required to improve security standards aimed at the building collapse risk reduction in densely urbanized areas.

Description: Published

Description: 1104

Description: 2T. Deformazione crostale attiva

Description: JCR Journal

Description: Two paroxysmal explosions occurred at Stromboli on July 3 and August 28, 2019, the first of which caused the death of a young tourist. After the first paroxysm an effusive activity began from the summit vents and affected the NW flank of the island for the entire period between the two paroxysms. We carried out an unsupervised analysis of seismic and infrasonic data of Strombolian explosions over 10 months (15 November 2018–15 September 2019) using a Self- Organizing Map (SOM) neural network to recognize changes in the eruptive patterns of Stromboli that preceded the paroxysms. We used a dataset of 14,289 events. The SOM analysis identified three main clusters that showed different occurrences with time indicating a clear change in Stromboli’s eruptive style before the paroxysm of 3 July 2019. We compared the main clusters with the recordings of the fixed monitoring cameras and with the Ground-Based Interferometric Synthetic Aperture Radar measurements, and found that the clusters are associated with different types of Strombolian explosions and different deformation patterns of the summit area. Our findings provide new insights into Strombolian eruptive mechanisms and new perspectives to improve the monitoring of Stromboli and other open conduit volcanoes.

Description: This work was supported by the project Progetto Strategico Dipartimentale INGV 2019 “Forecasting eruptive activity at Stromboli volcano: timing, eruptive style, size, intensity and duration” (FIRST). This work is also supported by a Marie Sklodowska-Curie Innovative Training Network Fellowship of the European Commission’s Horizon 2020 Programme under Contract Number 765710 INSIGHTS. This work benefited from the EU (DG ECHO) Project EVE n. 826292. This work has been partially supported by the “Presidenza del Consiglio dei Ministri–Dipartimento della Protezione Civile” (Presidency of the Council of Ministers–Department of Civil Protection; Scientific Responsibility: N.C.). However, this publication does not necessarily represent the official opinion and policies of the department.

Description: Published

Description: 1287

Description: 4V. Processi pre-eruttivi

Description: JCR Journal

Description: La Palma is one of the youngest of the Canary Islands, and historically the most active. The recent activity and unrest in the archipelago, the moderate seismicity observed in 2017 and 2018 and the possibility of catastrophic landslides related to the Cumbre Vieja volcano have made it strongly advisable to ensure a realistic knowledge of the background surface deformation on the island. This will then allow any anomalous deformation related to potential volcanic unrest on the island to be detected by monitoring the surface deformation. We describe here the observation results obtained during the 2006–2010 period using geodetic techniques such as Global Navigation Satellite System (GNSS), Advanced Differential Synthetic Aperture Radar Interferometry (A-DInSAR) and microgravimetry. These results show that, although there are no significant associated variations in gravity, there is a clear surface deformation that is spatially and temporally variable. Our results are discussed from the point of view of the unrest and its implications for the definition of an operational geodetic monitoring system for the island

Description: This research was mainly funded by the Spanish Ministerio de Ciencia, Innovación y Universidades research project DEEP-MAPS, grant agreement number RTI2018-093874-B-I00. It was also partially supported by the CSIC project 201530E019 and the project GEOSIR, grant agreement AYA2010-17448 from the Spanish Ministerio de Ciencia e Innovación.

Description: Published

Description: 2566

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

Description: JCR Journal

Description: The recent signs of reawakening at Campi Flegrei caldera (Southern Italy) received a great deal of attention due to the issues related to the volcanic risk management in a densely populated area. This paper explores relations between ground deformations, seismicity and geochemical time series in the time span 2004–2016. The aim is to unravel primary processes of unrest and the related indicators which may change in time. Data structure and interactions among variables were examined applying the clustering analysis, the correlations and the Granger causality test. The hierarchical agglomerative clustering detected two sub-periods which were further investigated. In both sub-period causal links were observed between variables while correlations did not appear and vice versa. Thus, well established formal approaches are required to study causal relations. Granger test results indicate that during 2004–2011 the awakening unrest could be mainly ascribed to hydrothermal system pressure fluctuations, probably induced by deep-rooted fluids injection, and that ground deformation together with CO2/H2O appears the most suitable geo-indicators. The 2011–2016 sub-period is characterized by enhanced dynamical connectivity. Granger test results suggest that the unrest is driven by a more localized and shallower thermohydromechanical engine. CO/CO2, He/CH4 and ground deformation velocity are mutually interacting appearing the most suitable geo-indicators.

Description: INGV Project PRIN n. 20174 × 3P29 FLUIDS

Description: Published

Description: 185

Description: 5V. Processi eruttivi e post-eruttivi

Description: 6V. Pericolosità vulcanica e contributi alla stima del rischio

Description: JCR Journal

Description: We present a novel inverse method for discriminating regional deformation and long-term fault creep by inversion of GNSS velocities observed at the spatial scale of intraplate faults by exploiting the different spatial signatures of these two mechanisms. In doing so our method provides a refined estimate of the upper bound of the strain accumulation process. As case study, we apply this method to a six year GNSS campaign (2003–2008) set up in the southern portion of the Pollino Range over the Castrovillari and Pollino faults. We show that regional deformation alone cannot explain the observed deformation pattern and implies high geodetic strain rate, with a WSW-ENE extension of 86±41×10−9/yr. Allowing for the possibility of fault creep, the modelling of GNSS velocities is consistent with their uncertainties and they are mainly explained by a shallow creep over the Pollino fault, with a normal/strike-slip mechanism up to 5 mm/yr. The regional strain rate decrease by about 70 percent and is characterized by WNW-ESE extension of 24±28×10−9/yr. The large uncertainties affecting our estimate of regional strain rate do not allow infering whether the tectonic regime of the area is extensional or strike-slip, although the latter is slightly more likely

Description: Published

Description: 2921

Description: 2T. Deformazione crostale attiva

Description: JCR Journal

Description: Seismic and geodetic moment-rate comparisons can reveal regions with unexpected potential seismic hazards. We performed such a comparison for the Southeastern Iberia—Maghreb region. Located at the western Mediterranean border along the Eurasia–Nubia plate convergence, the region has been subject to a number of large earthquakes (M ≥ 6.5) in the last millennium. To this end, on the basis of available geological, tectonic, and seismological data, we divided the study area into twenty-five seismogenic source zones. Many of these seismogenic source zones, comprising the Western Betics, the Western Rif mountains, and the High, Middle, and Saharan Atlas, are characterized by seismic/geodetic ratio values lower than 23%, evidencing their prevailing aseismic behavior. Intermediate seismic/geodetic ratio values (between 35% and 60%) have been observed for some zones belonging to the Eastern Betics, the central Rif, and the Middle Atlas, indicating how crustal seismicity accounts only for a moderate fraction of the total deformation-rate budget. High seismic/geodetic ratio values (〉 95%) have been observed along the Tell Atlas, highlighting a fully seismic deformation.

Description: The research performed in this study was partially supported by the Spanish CGL2015-65602-R, CGL2016-80687-R and RTI2018-093874-B-100 projects, and the Programa Operativo FEDER Andalucía 2014-2020 – call made by the University of Jaén 2018.

Description: Published

Description: 952

Description: 2T. Deformazione crostale attiva

Description: JCR Journal

Description: Gases present in the Earth crust are important in various branches of human activities. Hydrocarbons are a significant energy resource, helium is applied in many high-tech instruments, and studies of crustal gas dynamics provide insight in the geodynamic processes and help monitor seismic and volcanic hazards. Quantitative analysis of methane and CO2 migration is important for climate change studies. Some of them are toxic (H2S, CO2, CO); radon is responsible for the major part of human radiation dose. The development of analytical techniques in gas geochemistry creates opportunities of applying this science in numerous fields. Noble gases, hydrocarbons, CO2, N2, H2, CO, and Hg vapor are measured by advanced methods in various environments and matrices including fluid inclusions. Following the “Geochemical Applications of Noble Gases”(2009), “Frontiers in Gas Geochemistry” (2013), and “Progress in the Application of Gas Geochemistry to Geothermal, Tectonic and Magmatic Studies” (2017) published as special issues of Chemical Geology and “Gas geochemistry: From conventional to unconventional domains” (2018) published as a special issue of Marine and Petroleum Geology, this volume continues the tradition of publishing papers reflecting the diversity in scope and application of gas geochemistry.

Description: Published

Description: 976190

Description: 6A. Geochimica per l'ambiente e geologia medica

Description: JCR Journal

Description: Strombolian activity varies in magnitude and intensity and may evolve into a threat for the local populations living on volcanoes with persistent or semi-persistent activity. A key example comes from the activity of Stromboli volcano (Italy). The “ordinary” Strombolian activity, consisting in intermittent ejection of bombs and lapilli around the eruptive vents, is sometimes interrupted by high-energy explosive events (locally called major or paroxysmal explosions), which can affect very large areas. Recently, the 3 July 2019 explosive paroxysm at Stromboli volcano caused serious con- cerns in the local population and media, having killed one tourist while hiking on the volcano. Ma- jor explosions, albeit not endangering inhabited areas, often produce a fallout of bombs and lapilli in zones frequented by tourists. Despite this, the classification of Strombolian explosions on the basis of their intensity derives from measurements that are not always replicable (i.e., field surveys). Hence the need for a fast, objective and quantitative classification of explosive activity. Here, we use images of the monitoring camera network, seismicity and ground deformation data, to charac- terize and distinguish paroxysms, impacting the whole island, from major explosions, that affect the summit of the volcano above 500 m elevation, and from the persistent, mild explosive activity that normally has no impact on the local population. This analysis comprises 12 explosive events occurring at Stromboli after 25 June 2019 and is updated to 6 December 2020.

Description: This research was funded by the Project FIRST-ForecastIng eRuptive activity at Strom- boli volcano: Timing, eruptive style, size, intensity, and duration, INGV-Progetto Strategico Dipar- timento Vulcani 2019, (Delibera n. 144/2020; Scientific Responsibility: S.C.). This work was finan- cially supported by the “Presidenza del Consiglio dei Ministri—Dipartimento della Protezione Civile” (Presidency of the Council of Ministers–Department of Civil Protection) (DPC-UNIFI Agreement 2019–2021; Scientific Responsibility: N.C.). The contents of this paper represent the authors’ ideas and do not necessarily correspond to the official opinion and policies of the “Presi- denza del Consiglio dei Ministri–Dipartimento della Protezione Civile” (Presidency of the Council of Ministers–Department of Civil Protection).

Description: Published

Description: 944

Description: 6V. Pericolosità vulcanica e contributi alla stima del rischio

Description: JCR Journal

Description: Stromboli volcano has a persistent activity that is almost exclusively explosive. Predomi- nated by low intensity events, this activity is occasionally interspersed with more powerful episodes, known as major explosions and paroxysms, which represent the main hazards for the inhabitants of the island. Here, we propose a machine learning approach to distinguish between paroxysms and major explosions by using satellite-derived measurements. We investigated the high energy explosive events occurring in the period January 2018–April 2021. Three distinguishing features are taken into account, namely (i) the temporal variations of surface temperature over the summit area, (ii) the magnitude of the explosive volcanic deposits emplaced during each explosion, and (iii) the height of the volcanic ash plume produced by the explosive events. We use optical satellite imagery to compute the land surface temperature (LST) and the ash plume height (PH). The magnitude of the explosive volcanic deposits (EVD) is estimated by using multi-temporal Synthetic Aperture Radar (SAR) intensity images. Once the input feature vectors were identified, we designed a k-means unsupervised classifier to group the explosive events at Stromboli volcano based on their similarities in two clusters: (1) paroxysms and (2) major explosions. The major explosions are identified by low/medium thermal content, i.e., LSTI around 1.4 ◦C, low plume height, i.e., PH around 420 m, and low production of explosive deposits, i.e., EVD around 2.5. The paroxysms are extreme events mainly characterized by medium/high thermal content, i.e., LSTI around 2.3 ◦C, medium/high plume height, i.e., PH around 3330 m, and high production of explosive deposits, i.e., EVD around 10.17. The centroids with coordinates (PH, EVD, LSTI) are: Cp (3330, 10.7, 2.3) for the paroxysms, and Cme (420, 2.5, 1.4) for the major explosions.

Description: This research was partially funded by the Project FIRST—ForecastIng eRuptive activity at Stromboli volcano: timing, eruptive style, size, intensity, and duration, INGV—Progetto Strategico Dipartimento Vulcani 2019, (Delibera n. 144/2020).

Description: Published

Description: 4080

Description: 6V. Pericolosità vulcanica e contributi alla stima del rischio

Description: JCR Journal

Description: The comparison between crustal stress and surface strain azimuthal patterns has provided new insights into several complex tectonic settings worldwide. Here, we performed such a comparison for Egypt taking into account updated datasets of seismological and geodetic observations. In north-eastern Egypt, the stress field shows a fan-shaped azimuthal pattern with a WNW–ESE orientation on the Cairo region, which progressively rotated to NW–SE along the Gulf of Aqaba. The stress field shows a prevailing normal faulting regime, however, along the Sinai/Arabia plate boundary it coexists with a strike–slip faulting one (σ1 ≅ σ2 〉 σ3), while on the Gulf of Suez, it is characterized by crustal extension occurring on near-orthogonal directions (σ1 〉 σ2 ≅ σ3). On the Nile Delta, the maximum horizontal stress (SHmax) pattern shows scattered orientations, while on the Aswan region, it has a WNW–ESE strike with pure strike–slip features. The strain-rate field shows the largest values along the Red Sea and the Sinai/Arabia plate boundary. Crustal stretching (up to 40 nanostrain/yr) occurs on these areas with WSW–ENE and NE–SW orientations, while crustal contraction occurs on northern Nile Delta (10 nanostrain/yr) and offshore (~35 nanostrain/yr) with E–W and N–S orientations, respectively. The comparison between stress and strain orientations over the investigated area reveals that both patterns are near-parallel and driven by the same large-scale tectonic processes.

Description: This research was partially funded by the Programa Operativo FEDER Andalucía 2014-2020—A call made by the University of Jaén 2018.

Description: Published

Description: 1398

Description: 2T. Deformazione crostale attiva

Description: JCR Journal

Description: A comparative analysis of geodetic versus seismic moment-rate estimations makes it possible to distinguish between seismic and aseismic deformation, define the style of deformation, and also to reveal potential seismic gaps. This analysis has been performed for Egypt where the present-day tectonics and seismicity result from the long-lasting interaction between the Nubian, Eurasian, and Arabian plates. The data used comprises all available geological and tectonic information, an updated Poissonian earthquake catalog (2200 B.C.–2020 A.D.) including historical and instrumental datasets, a focal-mechanism solutions catalog (1951–2019), and crustal geodetic strains from Global Navigation Satellite System (GNSS) data. The studied region was divided into ten (EG-01 to EG-10) crustal seismic sources based mainly on seismicity, focal mechanisms, and geodetic strain characteristics. The delimited seismic sources cover the Gulf of Aqaba–Dead Sea Transform Fault system, the Gulf of Suez–Red Sea Rift, besides some potential seismic active regions along the Nile River and its delta. For each seismic source, the estimation of seismic and geodetic moment-rates has been performed. Although the obtained results cannot be considered to be definitive, among the delimited sources, four of them (EG-05, EG-06, EG-08, and EG-10) are characterized by low seismic-geodetic moment-rate ratios (〈20%), reflecting a prevailing aseismic behavior. Intermediate moment-rate ratios (from 20% to 60%) have been obtained in four additional zones (EG-01, EG-04, EG-07, and EG-09), evidencing how the seismicity accounts for a minor to a moderate fraction of the total deformational budget. In the other two sources (EG-02 and EG-03), high seismic-geodetic moment-rates ratios (〉60%) have been observed, reflecting a fully seismic deformation

Description: This research has been partially funded in the frame of the Programa Operativo FEDER Andalucía 2014–2020-call made by the University of Jaén, 2018.

Description: Published

Description: 7836

Description: 2T. Deformazione crostale attiva

Description: JCR Journal

Description: In July and August 2019, Stromboli volcano underwent two dangerous paroxysms previously considered “unexpected” because of the absence of significant changes in usually monitored parameters. We applied a multidisciplinary approach to search for signals able to indicate the possibility of larger explosive activity and to devise a model to explain the observed variations. We analysed geodetic data, satellite thermal data, images from remote cameras and seismic data in a timespan crossing the eruptive period of 2019 to identify precursors of the two paroxysms on a medium-term time span (months) and to perform an in-depth analysis of the signals recorded on a short time scale (hours, minutes) before the paroxysm. We developed a model that explains the observations. We call the model “push and go” where the uppermost feeding system of Stromboli is made up of a lower section occupied by a low viscosity, low density magma that is largely composed of gases and a shallower section occupied by the accumulated melt. We hypothesize that the paroxysms are triggered when an overpressure in the lower section is built up; the explosion will occur at the very moment such overpressure overcomes the confining pressure of the highly viscous magma above it.

Description: Published

Description: 4064

Description: 4V. Processi pre-eruttivi

Description: JCR Journal

Description: This paper presents a detailed geological map at the 1:20,000 scale of the Tocomar basin in the Central Puna (north-western Argentina), which extends over an area of about 80 km2 and displays the spatial distribution of the Quaternary deposits and the structures that cover the Ordovician basement and the Tertiary sedimentary and volcanic units. The new dataset includes litho-facies descriptions, stratigraphic and structural data and new 234U/230Th ages for travertine rocks. The new reconstructed stratigraphic framework, along with the structural analysis, has revealed the complex evolution of a small extensional basin including a period of prolonged volcanic activity with different eruptive centres and styles. The geological map improves the knowledge of the geology of the Tocomar basin and the local interplay between orogen-parallel thrusts and orogen-oblique fault systems. This contribution represents a fundamental support for in depth research and also for encouraging geothermal exploration and exploitation in the Puna Plateau region.

Description: Published

Description: id 5492

Description: 1TR. Georisorse

Description: JCR Journal

Description: In situ and remote-sensing measurements have been used to characterize the run-up phase and the phenomena that occurred during the August–November 2014 flank eruption at Stromboli. Data comprise videos recorded by the visible and infrared camera network, ground displacement recorded by the permanent-sited Ku-band, Ground-Based Interferometric Synthetic Aperture Radar (GBInSAR) device, seismic signals (band 0.02–10 Hz), and high-resolution Digital Elevation Models (DEMs) reconstructed based on Light Detection and Ranging (LiDAR) data and tri-stereo PLEIADES-1 imagery. This work highlights the importance of considering data from in situ sensors and remote-sensing platforms in monitoring active volcanoes. Comparison of data from live-cams, tremor amplitude, localization of Very-Long-Period (VLP) source and amplitude of explosion quakes, and ground displacements recorded by GBInSAR in the crater terrace provide information about the eruptive activity, nowcasting the shift in eruptive style of explosive to effusive. At the same time, the landslide activity during the run-up and onset phases could be forecasted and tracked using the integration of data from the GBInSAR and the seismic landslide index. Finally, the use of airborne and space-borne DEMs permitted the detection of topographic changes induced by the eruptive activity, allowing for the estimation of a total volume of 3.07 ± 0.37 × 106 m3 of the 2014 lava flow field emplaced on the steep Sciara del Fuoco slope.

Description: This work has been financially supported by the “Presidenza del Consiglio dei Ministri – Dipartimento della Protezione Civile” (Presidency of the Council of Ministers – Department of Civil Protection) within the framework of the InGrID2015-2016 and SAR.NET2017 projects (Scientific Responsibility: NC); this publication, however, does not reflect the position and the official policies of the Department. FDiT has been supported by a post-doc fellowship founded by the “Università degli Studi di Firenze – Ente Cassa di Risparmio di Firenze” (D.R. n. 127804 (1206) 2015; “Volcano Sentinel” project). This work has been financially supported by "Volcano Sentinel—extension” project (Call: “Settore ricerca scientifica e innovazione tecnologica”; founded by: Ente Cassa di Risparmio di Firenze. Scientific Responsibility: FeDiT).

Description: Published

Description: id 2035

Description: 5V. Processi eruttivi e post-eruttivi

Description: JCR Journal

Description: Here we present the results of the inversion of a new geodetic data set covering the 2012 Emilia seismic sequence and the following 1 year of postseismic deformation. Modeling of the geodetic data together with the use of a catalog of 3-D relocated aftershocks allows us to constrain the rupture geometries and the coseismic and postseismic slip distributions for the two main events (Mw 6.1 and 6.0) of the sequence and to explore how these thrust events have interacted with each other. Dislocation modeling reveals that the first event ruptured a slip patch located in the center of the Middle Ferrara thrust with up to 1 m of reverse slip. The modeling of the second event, located about 15 km to the southwest, indicates a main patch with up to 60 cm of slip initiated in the deeper and flatter portion of the Mirandola thrust and progressively propagated postseismically toward the top section of the rupture plane, where most of the aftershocks and afterslip occurred. Our results also indicate that between the two main events, a third thrust segment was activated releasing a pulse of aseismic slip equivalent to a Mw 5.8 event. Coulomb stress changes suggest that the aseismic event was likely triggered by the preceding main shock and that the aseismic slip event probably brought the second fault closer to failure. Our findings show significant correlations between static stress changes and seismicity and suggest that stress interaction between earthquakes plays a significant role among continental en echelon thrusts.

Description: Published

Description: 4742–4766

Description: 1T. Deformazione crostale attiva

Description: 2T. Sorgente Sismica

Description: 3T. Storia Sismica

Description: JCR Journal