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I terremoti nell'area di Chiusdino e della Val di Merse/Materiali per una storia dei terremoti a Chiusdino e in Val di Merse
No full textChi scrive si è occupata di ricerca storica sui terremoti di Siena e del Senese dall’ultimo decennio del Novecento partecipando a iniziative che vanno dal recupero del patrimonio informativo della “tradizione sismologica” all’analisi critica delle schede di Baratta, alle ricerche storiche su singoli terremoti, al censimento di terremoti “sconosciuti” e all’esplorazione di temi tangenziali alla sismologia storica, come le reazioni e risposte pubbli- che e private, amministrative e culturali, civili e religiose delle comunità poste a confronto col terremoto. In questi anni non sono mai state avviate ricerche specifiche su Chiusdino e la Val di Merse. Sono però stati occasionalmente raccolti dati sul territorio in questione e di essi si proverà qui a dar conto. Dopo un’introduzione sugli studi di sismologia storica italiana e il loro retroterra culturale si analizza la “storia sismica” di Chiusdino (avanzamento gennaio 2022), si riporta uno stato di avanzamento su tre più significativi terremoti che abbiano interessato la Val di Merse (Provincia di Siena) tra il 1000 e oggi e si fornisce un breve excursus sulle vicende sismiche che hanno coinvolto a vario titolo la comunità di Chiusdino, tra monitoraggio dei terremoti, iniziative di solidarietà e “invenzione della tradizione”. In appendice una Cronologia di testimonianze storiche sui terremoti a Chiusdino.Accademia Galganiana (Chiusdino, SI).Published69-964T. Sismicità dell'ItaliaN/A or not JC
An Analytic Expression for the Volcanic Seismic Swarms Occurrence Rate. A Case Study of Some Volcanoes in the World
No full textSeismic swarms are defined as a group of earthquakes occurring very close in time and space but without any distinctively large event triggering their occurrence. Up to now no simple law has been found to describe the swarm occurrence rate. Here we find an expression able to fit the average occurrence rate on some volcanic areas. This expression exhibits some differences in respect to the classical Omori law. Namely the c parameter of the Omori law is equal to zero and the power law decay of the average occurrence rate of the earthquakes is followed by an exponential decaying regime. Both the results can be interpreted in term of fluid injection and/or movements. Indeed this is a more impulsive phenomenon compared to the occurrence of a large earthquake, with a duration compatible with a c = 0. The exponential decay following the power law one could be explained by a viscoelastic relaxation of the stress induced by the injection and/or movements of fluids in the earth crust.Publishede2022EA002534OSV2: Complessità dei processi vulcanici: approcci multidisciplinari e multiparametriciJCR Journa
The Sicilian Countryside in the Early Middle Ages: Human–Environment Interactions at Contrada Castro
No full textWithin the project ‘Harvesting Memories: Ecology and Archaeology of Monti Sicani Landscapes’, this paper aims to reconstruct human–environment interactions in the inland areas of Western Sicily during the Early Middle Ages through a comparative analysis of environmental archaeological data. We analyse carpological and anthracological finds and faunal remains originating from different layers of the rural settlement of Contrada Castro (Corleone, Palermo), excavated in 2017–2019. The site was mainly occupied between the Byzantine and Islamic periods (late 8th to 11th c. AD). The examination of wood charcoal enabled the identification of plant species selected and exploited in the landscape of the site for each main chronological period. The archaeobotanical data indicated a precise, qualitative picture on the historical vegetation of this area, accompanied with the agricultural practices of the communities. The zooarchaeological data added further information on the reconstruction of rural economy and animal exploitation patterns. An integrated comparison of the characteristic landscape and the archaeobotanical and zooarchaeological data presented the dynamics of agricultural strategy, wood exploitation, and management of animal resources of an early medieval rural community in Western SicilyPublished240-2557SR AMBIENTE – Servizi e ricerca per la societàJCR Journa
Accuracy of hmF2 estimations, including IRI-2020 options and ionograms validated parameters, compared to ISR measurements at Millstone Hill
No full textSeveral empirical formulations used over time to estimate the fundamental ionospheric parameter hmF2 have been compared in this study. These are the first formulation proposed by Shimazaki (1955) (SHI-1955) as a function of the propagation parameter M(3000)F2, the more accurate BSE-1979 formula proposed by Bilitza et al. (1979) and firstly adopted by the International Reference Ionosphere (IRI) model, and the newest Altadill-Magdaleno-Torta-Blanch (AMTB-2013) (Altadill et al., 2013) and SHU-2015 (Shubin, 2015) models, obtained with a different approach with no explicit dependence on any ionospheric parameter and added as alternative options in the IRI-2016. The evaluation of the accuracy of the available formulation is performed by comparing the modeled values of hmF2 with those simultaneously obtained with independent measurements from the Incoherent Scatter Radar (ISR) installed at the Millstone Hill ionospheric station. The database considered consists of 3626 measurements, thus allowing the evaluation of the results for different heliogeophysical conditions. SHI-1955 and BSE-1979 formulations are evaluated also using input data manually scaled from ionograms recorded at the same location, with the aim of evaluating their accuracy when updated with validated data rather than modeled ones. The SHU-2015 is confirmed the best option in any condition, while AMTB-2013 turns out to perform poorly during night, when SHI-1955 and BSE-1979 fed by validated data can be used for trend analyses due to the high correlation with ISR data. Despite this, BSE-1979 performs better with modeled parameters as input, in terms of RMSE and mean deviation from ISR data. The use of SHI-1955 with CCIR-modeled M(3000)F2 is discouraged under daytime conditions even for long trend analyses.Published3202-3211OSA3: Climatologia e meteorologia spazialeJCR Journa
Mantellic degassing of helium in an extensional active tectonic setting at the front of a magmatic arc (central Mexico)
No full textThe physicochemical and isotopic characteristics of groundwater and dissolved gas of central Mexico provide valuable information about the geologic
and tectonic context of the area. Low–high-enthalpy manifestations (up to 98 °C
in springs and more than 100 °C in geothermal wells) are distributed within the
San Juan del Río, Querétaro, and Celaya hydrologic basins, located at the boundary between the current Mexican magmatic arc and an extensional continental
area with intraplate volcanism called Mesa Central Province. Groundwaters in
the study area represent a mixture between the cold water end-member with a
Ca2+-Mg2+-HCO3- composition and a hydrothermal end-member enriched in Na+ , K+ , SO4 2−, and Cl-. Cold and hot groundwaters δ2
H and δ18O plot along the same evaporation lines and do not exhibit a magmatic input. Dissolved and free gas do not
show a typical volcanic composition signature. He and Ne isotope composition
provide evidence of an important contribution of non-atmospheric noble gases.
Although helium composition mainly has a crustal origin (21–83%), the mantellic
contribution (1–39%) is higher than expected for an area lacking recent volcanism.
A volatile-rich magma aging at depth was discarded as the source of this mantellic helium signature but points out a recent mantellic contribution. Thus, we
propose that mantellic helium comes from the sublithospheric mantle into the
shallow crust through the highly permeable tectonic boundaries between the
geologic provinces, namely the N−S Taxco−San Miguel de Allende and ChapalaTula fault systems. Mantellic helium flow rates through these fault systems were
estimated to have values ranging from 0.1 m/yr to 2.9 m/yr. This He flux range
implies that aside from subduction, mantle volatile degassing enhanced by
crustal fault systems is the main degassing process in the region studied.Published335–3473V. Proprietà chimico-fisiche dei magmi e dei prodotti vulcaniciJCR Journa
A Reliable Procedure to Estimate the Rupture Propagation Directions from Source Directivity: The 2016–2018 Central Italy Seismic Sequence
No full textWe present a new approach to estimate the predominant direction of rupture propagation
during a seismic sequence. A fast estimation of the rupture propagation direction is
essential to knowthe azimuthal distribution of shaking around the seismic source and the
associated risks for the earthquake occurrence. The main advantage of the proposed
method is that it is conceptually reliable, simple, and fast (near real time). The approach
uses the empirical Green’s function technique and can be applied directly to the waveforms
without requiring the deconvolution of the instrumental response and without
knowing a priori the attenuation model and the orientation of the activated fault system.
We apply the method to the 2016–2017 Amatrice-Visso-Norcia high-energy and long-lasting
earthquake series in central Italy,which affected a large area up to 80 kmalong strike,
withmore than 130,000 events of small-to-moderate magnitude recorded until the end of
August 2022. Most of the selected events analyzed in this study have a magnitude
greater than 4.4 and only four seismic events have a magnitude in the range of 3.3–3.7.
Our results show that the complex activated normal fault system has a rupture direction
mainly controlled by the pre-existing normal faults and by the orientation of the reactivated
faults. In addition, the preferred direction of rupture propagation is also controlled
by the presence of fluid in the pre-existing structural discontinuities. We
discuss the possible role of fluids as a cause of bimaterial interface. Another important
finding from our analysis is that the spatial evolution of seismicity is controlled by the
directivity.Published1912–1924JCR Journa
TESLA, A Tool for Automatic Earthquake Low-Frequency Spectral Level Estimation: The Study of 2013 St. Gallen Earthquake Fault-Plane Solutions
No full textOne of the challenges of seismicity monitoring is to achieve multiparametric catalogs complete down to small magnitude using automatic procedures. This can be obtained using seismic networks with high performance and robust, automatic algorithms able to process large data sets, limiting the manual operations of the analysts. The characterization of microseismicity is fundamental to study its spatial and temporal evolution and to define the seismic activity of fault systems. Among the source parameters of microseismic events, focal mechanisms are not generally calculated and, when available in the seismic catalog, their reliability may be dubious. We propose a new tool, named Tool for automatic Earthquake low‐frequency Spectral Level estimAtion (TESLA), to automatically calculate the P‐ and S‐wave low‐frequency spectral levels. Indeed, it has been shown that these levels can be inverted together with P‐phase polarities to better constrain the focal mechanism or to estimate the seismic moment. TESLA is designed to invert the P‐ and S‐displacement spectra searching the optimal signal window to use for the spectral analysis. Using a signal window of fixed duration, although variable according to the earthquake magnitude, is not always the appropriate choice, especially when microseismicity is analyzed. TESLA performs three main tasks for both P and S phases: (1) a systematic exploration of several signal windows to use for the computation of displacement spectra, (2) the spectral analysis for all the selected signal windows, and (3) the evaluation of the best‐displacement spectra through quantitative criteria and the estimation of the low‐frequency spectral levels. The tool is first validated and then applied to the 2013 St. Gallen, Switzerland, induced seismic sequence to calculate the P and S low‐frequency spectral level ratios, which are inverted to estimate focal mechanisms. Our results show the robustness of the tool to process microseismicity and the benefit of using it to automatically analyze large waveform data sets.Published2441-2455JCR Journa
Effects of Hydrothermal Alteration and Mineralization on the Paleomagnetic Properties of Rocks from IODP Expedition 376 at Brothers Volcano
No full textThe 3-D subseafloor architecture of submarine hydrothermal systems is largely unknown, particularly at arc volcanoes. The alteration of volcanic rocks in these systems produces dramatic changes in their magnetic prop- erties. Here, we present the first comprehensive study of paleomagnetic measurements from oriented samples of hydrothermally altered dacites from Brothers volcano (Kermadec arc), drilled during International Ocean Discovery Program (IODP) Expedition 376. These data have enabled insight into the progressive evolution of magnetic minerals in subseafloor volcanic rocks affected by variable types and degrees of hydrothermal alteration in response to varying fluid temperatures, chemistry, and associated mineralization; from initial chlo- ritization typical of relatively low-temperature interaction with seawater to extremely altered rocks affected by higher-temperature, very acidic magmatic fluids.
Hydrothermally altered samples show a significant reduction in natural remanent magnetization intensity (10–4 to 10–2 A/m) compared with unaltered samples (1–10 A/m), suggesting that primary titanomagnetite grains are destroyed during the hydrothermal alteration process. Except for a small region in proximity to the mineral- ized stockwork zone, no chemical remanent magnetization is observed in association with hydrothermal altera- tion, consistent with the widespread formation of diamagnetic and/or paramagnetic minerals such as pyrite, rutile, and leucoxene, which do not carry any natural remanent magnetization.
Demagnetization experiments show that most of the oriented samples possess a stable characteristic rema- nent magnetization induced by the residual primary magnetic minerals formed at the time the rocks cooled on the sea floor. Partially chloritized dacites, however, are characterized by large magnetic susceptibilities, low Koenigsberger ratios, and very low magnetic coercivities, consistent with initial dissolution of smaller, single- domain magnetic grains, indicating that intensely hydrothermally altered rocks are better paleomagnetic indica- tors than initially chloritized samples at the periphery of the hydrothermal systems.
The significant magnetic contrast between fresh and hydrothermally altered rocks, in addition to a thick layer (>300 m) of demagnetized rocks observed at Brothers volcano, confirms the empirical results that magnetic anomalies are important geophysical tools to determine the geometry of hydrothermal systems at submarine arc volcanoes.Published1605–1627OSA1: Variazioni del campo magnetico terrestre, imaging crostale e sicurezza del territorioJCR Journa
Slip localization on multiple fault splays accommodating distributed deformation across normal fault complexities
No full textDeformation across structural complexities such as along-strike fault bends may be accommodated by distributed faulting, with multiple fault splays working to transfer the deformation between two principal fault segments. In these contexts, an unsolved question is whether fault activity is equally distributed through time, with multiple fault splays recording the same earthquakes, or it is instead localized in time and space across the distributed faults, with earthquakes being clustered on specific fault splays. To answer this question, we studied the distributed deformation across a structural complexity of the Mt. Marine fault (Central Apennines, Italy), where multiple fault splays accommodate the deformation throughout the change in strike of the fault. Our multidisciplinary (remote sensing analysis, geomorphological-geological mapping, geophysical and paleoseismological surveys) study identified five principal synthetic and antithetic fault splays arranged over an across-strike distance of 500 m, all of which showing evidence of multiple surface-rupturing events during the Late Pleistocene-Holocene. The fault splays exhibit different and variable activity rates, suggesting that fault activity is localized on specific fault splays through space and time. Nonetheless, our results suggest that multiple fault splays can rupture simultaneously during large earthquakes. Our findings have strong implications on fault-based seismic hazard assessments, as they imply that data collected on one splay may not be representative of the behaviour of the entire fault. This can potentially bias seismic hazard calculations.This work was realized under the agreement between the University of Chieti-Pescara (Dep. INGEO) and the National Institute of Geophysics and Vulcanology (INGV): “Ridefinizione delle Zone di Attenzione delle Faglie Attive e Capaci emerse dagli studi di microzonazione sismica effettuati nel territorio dei Centri abitati di Barete e Pizzoli in provincia de L'Aquila, interessati dagli eventi sismici verificatisi a far data dal 24 agosto 2016”, funded by the Commissioner structure for post-earthquake reconstruction of the Italian Government.Published230075OST2 Deformazione e Hazard sismico e da maremotoJCR Journa
FAIR Research Objects for realizing Open Science with RELIANCE EOSC project
No full textThe numerous benefits of Open Science (OS) and of the four FAIR foundational principles
-Findable, Accessible, Interoperable and Reusable- are increasingly valued in academia,
although what OS and FAIR entail is still largely misunderstood. In such conditions putting
in practice OS and applying the FAIR principles is challenging and underrated. However,
realising OS is perfectly within grasp provided that an infrastructure supporting the
management of the research lifecycle is available. RoHub is precisely a Research
Object (RO) management platform implementing three complementary technologies:
Research Objects, Data Cubes and Artificial Intelligence-based Text Mining services.
RoHub enables researchers to collaboratively manage, share and preserve their research
while they are still working on it (rather than after the work is finished). In this paper, three
communities from Earth Sciences, namely Geohazards, Sea Monitoring and Climate
Change, demonstrate how RoHub helped them to understand each other and to work
openly, and more importantly how communities of practice play an important role in
facilitating reuse and interdisciplinary collaboration. These findings are illustrated with
several use cases from these various communities.Publishede1087655IT. Osservazioni satellitariN/A or not JC