OA Earth-prints Repository
Not a member yet
16457 research outputs found
Sort by
New Record Ocean Temperatures and Related Climate Indicators in 2023
No full textThe global physical and biogeochemical environment has been substantially altered in response to increased atmospheric greenhouse gases from human activities. In 2023, the sea surface temperature (SST) and upper 2000 m ocean heat content (OHC) reached record highs. The 0–2000 m OHC in 2023 exceeded that of 2022 by 15 ± 10 ZJ (1 Zetta Joules = 1021 Joules) (updated IAP/CAS data); 9 ± 5 ZJ (NCEI/NOAA data). The Tropical Atlantic Ocean, the Mediterranean Sea, and southern oceans recorded their highest OHC observed since the 1950s. Associated with the onset of a strong El Niño, the global SST reached its record high in 2023 with an annual mean of ~0.23°C higher than 2022 and an astounding > 0.3°C above 2022 values for the second half of 2023. The density stratification and spatial temperature inhomogeneity indexes reached their highest values in 2023.PublishedOSA4: Ambiente marino, fascia costiera ed Oceanografia operativaJCR Journa
Simulated Seismicity as a Tool for Studying the Long-Term Seismogenic Process: An Italy–Japan Comparison
No full textIn this study, we aimed to assess the capacity of a physics-based earthquake simulator to
improve our understanding of the seismogenic process. In this respect, we applied a previously tested
earthquake simulator to two well-known and completely different seismogenic fault systems, namely
the Italian Apennines and the Nankai subduction in Japan, for which long historical records of strong
earthquakes are available. They are characterized by different fault mechanisms, fault sizes, and
slip rates. Because of the difference in slip rates, the time scale of the seismicity patterns is different
for the two systems (several hundreds of years for the Apennines and a few tens of years for the
Nankai Fault). The results of simulations that produced synthetic catalogues of 100,000 years show
these significant long-term seismicity patterns characterizing the seismic cycles for both seismogenic
areas as follows: The average stress and the occurrence rate of earthquakes increase in the long
term as the next major earthquake approaches; while the average stress increases uniformly, the
occurrence rate stops increasing well in advance of the mainshocks; the b-value exhibits a long-term
increase before major earthquakes and a fast decrease shortly before the mainshocks. Even if no
specific statistical tool was applied for the quantification of the similarities between the seismicity
patterns of the two seismic areas, such similarities are clearly justified by the large number of seismic
cycles included in the 100,000-year synthetic catalogues. The paper includes a discussion on the
capability of the simulation algorithm to reliably represent the real long-term seismogenic process.
This question is difficult to answer because the available historical observations are of too short a
duration to provide significant statistical results. In spite of the limitations characterizing the use of
earthquake simulators for time-dependent earthquake hazard assessment, and the lack of convincing
mechanistic explanations of the specific seismic patterns reproduced by our simulator algorithm, our
results encourage further investigations into the application of simulators for the development of
seismogenic models, including short-term features.Published7900OST1 Alla ricerca dei Motori GeodinamiciOST3 Vicino alla fagliaJCR Journa
Publication Preview Source Reprocessing of XBT profiles from the Ligurian and Tyrrhenian seas over the time period 1999–2019 with full metadata upgrade
No full textThe advent of open science and the United Nations Decade of Ocean Science for Sustainable Development are revolutionizing the ocean data sharing landscape for an efficient and transparent ocean information and knowledge generation. This blue revolution raised awareness on the importance of metadata and community standards to actionate interoperability of the digital assets (data and services) and guarantee that data driven science preserve provenance, lineage and quality information for its replicability. Historical data are frequently not compliant with these criteria, lacking metadata information that was not retained crucial at the time of the data generation and further ingestion into marine data infrastructures. The present data review is an example attempt to fill this gap through a thorough data reprocessing starting from the original raw data and operational log sheets. The data gathered using XBT (eXpendable BathyThermograph) probes during several monitoring activities in the Tyrrhenian and Ligurian Seas between 1999 and 2019 have been first formatted and standardized according to the latest community best practices and all available metadata have been inserted, including calibration information never applied. Secondly, a new automatic Quality Control (QC) procedure has been developed and a new interpolation scheme applied. The reprocessed (REP) dataset has been compared to the present data version, available from SeaDataNet data access portal through the saved query Url https://cdi.seadatanet.org/search/welcome.php?query=1866&query_code={4E510DE6-CB22-47D5-B221-7275100CAB7F}, processed according to the pioneering work of Manzella et al. (2003) conducted in the framework of the EU Mediterranean Forecasting System Pilot Project (Pinardi et al., 2003). The maximum discrepancy among the REP and SDN data versions resides always within the surface layer (REP profiles are warmer than SDN ones) until 150 m depth, generally when the thermocline settles (from May to November). The overall bias and root mean square difference are equal to 0.002 °C and 0.041 °C, respectively. Such differences are mainly due to the new interpolation technique (Barker and McDougall, 2020), the lack of filtering and the application of the calibration correction in the REP dataset. The REP dataset (Reseghetti et al., 2023; https://doi.org/10.13127/rep_xbt_1999_2019) is available and accessible through the INGV ERDDAP server (http://oceano.bo.ingv.it/erddap/index.html), which allows machine to machine data access in compliance with the FAIR (Findable, Interoperable, Accessible, Reusable) principles (Wilkinson et al., 2016).In pressOSA4: Ambiente marino, fascia costiera ed Oceanografia operativaJCR Journa
Evolution in unrest processes at Campi Flegrei caldera as inferred from local seismicity
No full textChanges in seismicity with time and location are diagnostic signals for understanding the dynamics of volcanic
unrest. We used these signals at the Campi Flegrei caldera, in southern Italy, to investigate how structural
changes have determined three styles of unrest since 1982, distinguished by a ground uplift (measured at Pozzuoli, near the centre of the caldera) of 178 cm in 1982–84; a subsidence of 93 cm in 1985–2005; and an uplift of 118 cm between 2005 and November 2023. Double-difference seismic locations and concentrations of seismic energy release have revealed impermeable horizons that correspond to the cap rock and self-sealed base of the
geothermal system at depths of 1.5 and 3 km, respectively. Most earthquakes have been shallower than 3 km,
consistent with the brittle upper crust being stretched over a zone of pressurization below the geothermal system.
The 1982–84 uplift decayed after a major seismic swarm on April 1st, 1984, breached the lower impermeable
horizon, which increased the flux of escaping gas and reduced the source pressure. Continued gas escape promoted subsidence until the lower horizon had resealed itself and initiated a new episode of uplift while gas from depth re-accumulated beneath. Compared with 1982–84, a greater proportion of recent seismicity has occurred at shallower depths below the actively degassing fumaroles of Solfatara-Pisciarelli, north-east of Pozzuoli. The associated high seismic b-values, between 1 and 2, are consistent with high fluid pressures and, hence, with locations more favourable to fracturing. Continued uplift may thus persist until fracturing of the shallow crust allows faster rates of gas release and depressurization of the pressure source.Published118530OSV2: Complessità dei processi vulcanici: approcci multidisciplinari e multiparametriciJCR Journa
From the detection of monitoring anomalies to the probabilistic forecast of the evolution of volcanic unrest: an entropy-based approach
No full textOwing to the current lack of plausible and exhaustive physical pre-eruptive models, often volcanologists rely on the observation of monitoring anomalies to track the evolution of volcanic unrest episodes. Taking advantage from the work made in the development of Bayesian Event Trees (BET), here we formalize an entropy-based model to translate the observation of anomalies into probability of a specific volcanic event of interest. The model is quite general and it could be used as a stand-alone eruption forecasting tool or to set up conditional probabilities for methodologies like the BET and of the Bayesian Belief Network (BBN). The proposed model has some important features worth noting: (i) it is rooted in a coherent logic, which gives a physical sense to the heuristic information of volcanologists in terms of entropy; (ii) it is fully transparent and can be established in advance of a crisis, making the results reproducible and revisable, providing a transparent audit trail that reduces the overall degree of subjectivity in communication with civil authorities; (iii) it can be embedded in a unified probabilistic framework, which provides an univocal taxonomy of different kinds of uncertainty affecting the forecast and handles these uncertainties in a formal way. Finally, for the sake of example, we apply the procedure to track the evolution of the 1982–1984 phase of unrest at Campi Flegrei.Published5OSV1: Verso la previsione dei fenomeni vulcanici pericolosiJCR Journa
Sovranità digitale: DPO, protezione dei dati e cybersicurezza
No full textLa sovranità digitale ha tra le sue iniziali priorità la difesa del perimetro cibernetico al cui interno si trova anche il dato personale, vero asset strategico di ogni pubblica amministrazione (PA) l'insieme delle quali formano i punti di contatto tra cittadino e Stato. La protezione del dato richiede diverse abilità specialistiche distribuite spesso tra più figure.
Digital sovereignty has among its initial priorities the defense of the cyber perimeter, within which personal data is also found—a true strategic asset for every public administration (PA). Together, these administrations form the points of contact between citizens and the State. Data protection requires various specialized skills, often distributed among multiple roles.Published96-99OS: Terza mission
Hydrology Drives Crustal Deformation and Modulates Seismicity in the Matese Massif (Italy)
No full textWe analyze the interplay between hydrology, deformation and seismicity in the Matese massif, located in the Italian Southern Apennines. We find that this area is characterized by the concurrent action of two hydrologically-driven processes: the first is the deformation detected by GNSS data in the shallowest part (above the elevation of the major springs) of the Earth crust, in phase with the hydrological forcing; the second is the triggering of seismicity at depth with a delay suggesting a downward diffusive process.
We study the first process by applying a Principal Component Analysis to the GNSS displacements time series, aiming to identify a common signal describing the largest data variance. We find that the maximum horizontal displacements associated with the first principal component (PC1) are larger than 1 cm in two GNSS sites and the PC1 temporal evolution is well correlated and in phase with the flow of the largest spring of the region, which we consider as proxy of the water content of the massif. This suggests that the main source of horizontal deformation is the water content fluctuations in the shallow portion of the Matese aquifer, in particular within fractures located in correspondence of the main mapped faults. The deformation rates caused by this process are one order of magnitude larger than the tectonic ones.
Finally, we infer the second process by observing the correlation between the background seismicity and the spring discharge with a time lag of 121 days. In our interpretation, downward diffusive processes, driven by aquifer water content variations, propagate pore pressure waves that affect the faults strength favoring the occurrence of micro-earthquakes. This is supported by the values of hydraulic diffusivity (1.5 m^2/s) and rock permeability (3.2-3.8⋅10^−13 m^2), which are compatible with what is observed in karstified limestones.Published1899–1912OST2 Deformazione e Hazard sismico e da maremotoJCR Journa
Seismic monitoring using the telecom fiber network
No full textLaser interferometry enables to remotely measure microscopical length changes of deployedtelecommunication cables originating from earthquakes. Long reach and compatibility with datatransmission make it attractive for the exploration of both remote regions and highly-populated areaswhere optical networks are pervasive. However, interpretation of its response still suffers from a limitednumber of available datasets. We systematically analyze 1.5 years of acquisitions on a land-basedtelecommunication cable in comparison to co-located seismometers, with successful detection ofevents in a broad magnitude range, including very weak ones. We determine relations between acable’s detection probability and the events magnitude and distance, introducing spectral analysis offiber data as a tool to investigate earthquake dynamics. Our results reveal that quantitative analysis ispossible, confirming applicability of this technique both for the global monitoring of our planet and thedaily seismicity monitoring of populated areas, in perspective exploitable for civilian protectionPublished178OST2 Deformazione e Hazard sismico e da maremotoOST5 Verso un nuovo MonitoraggioJCR Journa
Ionosonde Measurement Comparison during an Interplanetary Coronal Mass Ejection (ICME)- and a Corotating Interaction Region (CIR)-Driven Geomagnetic Storm over Europe
No full textA comparison of three types of ionosonde data from Europe during an interplanetary coronal mass ejection (ICME)- and a corotating interaction region (CIR)-driven geomagnetic storm event is detailed in this study. The selected events are 16–20 March 2015 for the ICME-driven storm and 30 May to 4 June 2013 for the CIR-driven one. Ionospheric data from three European ionosonde stations, namely Pruhonice (PQ), Sopron (SO) and Rome (RO), are investigated. The ionospheric F2-layer responses to these geomagnetic events are analyzed with the ionospheric foF2 and h’F2 parameters, the calculated deltafoF2 and deltahF2 values, the ratio of total electron content (rTEC) and Thermosphere, Ionosphere, Mesosphere, Energetics and Dynamics (TIMED) satellite Global Ultraviolet Imager (GUVI) thermospheric [O]/[N2] measurement data. The storm-time and the quiet-day mean values are also compared, and it can be concluded that the quiet-day curves are similar at all the stations while the storm-time ones show the latitudinal dependence during the development of the storm. As a result of the electron density comparison, during the two events, it can be concluded that the sudden storm commencement (SSC) that characterized the ICME induced a traveling atmospheric disturbance (TAD) seen in the European stations in the main phase, while this is not seen in the CIR-driven ionospheric storm, which shows a stronger and more prolonged negative effect in all the stations, probably due to the season and the depleted O/N2 ratio.Published344OSA3: Climatologia e meteorologia spazialeJCR Journa
Earthquakes Parameters from Citizen Testimonies: A Retrospective Analysis of EMSC Database
No full textWe aim to compute macroseismic parameters (location and magnitude) using the BOXER
code for the first time on the citizen testimonies, that is, individual intensity data points
(IDPs) at the global scale collected and made available by the LastQuake system of the
European–Mediterranean Seismological Centre (EMSC). IDPs available for different earthquakes
are selected to eliminate those that are geographically inconsistent with most
data; then they are clustered spatially based on various methods. For each cluster with
at least three IDPs, a macroseismic data point (MDP), corresponding to an intensity value
assessed for given localities as in classical macroseismic studies, is computed by various
central tendency estimators (average, median, and trimmed averages). Finally, macroseismic
parameters are obtained by MDP distribution using two location methods of BOXER
code. For each earthquake, we used raw and corrected intensities and 132 different combinations
of grouping methods, estimators, and BOXER methods. We assigned a ranking
to the combinations that best reproduce instrumental parameters and used such a ranking
to select preferred combinations for each earthquake. We analyzed retrospectively
the reliability of the parameters as a function of time and space. The results are essentially
identical using original and corrected intensities and show higher reliability for BOXER’s
method 1 than for method 0; they are dependent on the geographical area, and generally
improve over time and with the number of IDPs collected. These findings are useful for
the future real-time analyses, and for evaluating the location and magnitude of earthquakes
whenever a sufficient number of IDPs are available and with a distribution such
that MDPs can be derived and the BOXER method applied.Published969–996OST4 Descrizione in tempo reale del terremoto, del maremoto, loro predicibilità e impattoJCR Journa