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IMEX_SfloW2D v2: a depth-averaged numerical flow model for volcanic gas–particle flows over complex topographies and water
No full textWe present developments to the physical model and the open-source numerical code IMEX_SfloW2D (de' Michieli Vitturi et al., 2019). These developments consist of a generalization of the depth-averaged (shallow-water) fluid equations to describe a polydisperse fluid–solid mixture, including terms for sedimentation and entrainment, transport equations for solid particles of different sizes, transport equations for different components of the carrier phase, and an equation for temperature/energy. Of relevance for the simulation of volcanic mass flows, vaporization and entrainment of water are implemented in the new model. The model can be easily adapted to simulate a wide range of volcanic mass flows (pyroclastic avalanches, lahars, pyroclastic surges), and here we present its application to transient dilute pyroclastic density currents (PDCs). The numerical algorithm and the code have been improved to allow for simulation of sub- to supercritical regimes and to simplify the setting of initial and boundary conditions. The code is open-source. The results of synthetic numerical benchmarks demonstrate the robustness of the numerical code in simulating transcritical flows interacting with the topography. Moreover, they highlight the importance of simulating transient in comparison to steady-state flows and flows in 2D versus 1D. Finally, we demonstrate the model capabilities to simulate a complex natural case involving the propagation of PDCs over the sea surface and across topographic obstacles, through application to Krakatau volcano, showing the relevance, at a large scale, of non-linear fluid dynamic features, such as hydraulic jumps and von Kármán vortices, to flow conditions such as velocity and runout.Ministero dell'Istruzione, dell'Università e della Ricerca (“Fondo finalizzato al rilancio degli investimenti delle amministrazioni centrali dello Stato e allo sviluppo del Paese”, legge 145/2018), Horizon 2020 (EUROVOLC Transnational Access Grant) and the Natural Environment Research Council (grant nos. NE/T002026/1 and NE/S003509/1)Published6309–6336OSV2: Complessità dei processi vulcanici: approcci multidisciplinari e multiparametriciJCR Journa
Deep magma degassing and volatile fluxes through volcanic hydrothermal systems: Insights from the Askja and Kverkfjöll volcanoes, Iceland
No full textMantle volatiles are transported to Earth’s crust and surface by basaltic volcanism. During subaerial eruptions,
vast amounts of carbon, sulfur and halogens can be released to the atmosphere during a short time-interval, with
impacts ranging in scale from the local environment to the global climate. By contrast, passive volatile release at
the surface originating from magmatic intrusions is characterized by much lower flux, yet may outsize eruptive
volatile quantities over long timescales. Volcanic hydrothermal systems (VHSs) act as conduits for such volatile
release from degassing intrusions and can be used to gauge the contribution of intrusive magmatism to global
volatile cycles. Here, we present new compositional and isotopic (δD and δ18O-H2O, 3He/4He, δ13C-CO2, Δ33S-
δ34S-H2S and SO4) data for thermal waters and fumarole gases from the Askja and Kverkfj¨oll volcanoes in central
Iceland. We use the data together with magma degassing modelling and mass balance calculations to constrain
the sources of volatiles in VHSs and to assess the role of intrusive magmatism to the volcanic volatile emission
budgets in Iceland.
The CO2/ΣS (10 30), 3He/4He (8.3–10.5 RA; 3He/4He relative to air), δ13C-CO2 ( 4.1 to 0.2 ‰) and Δ33S-
δ34S-H2S ( 0.031 to 0.003 ‰ and 1.5 to +3.6‰) values in high-gas flux fumaroles (CO2 > 10 mmol/mol) are
consistent with an intrusive magmatic origin for CO2 and S at Askja and Kverkfj¨oll. We demonstrate that deep
(0.5–5 kbar, equivalent to ~2–18 km crustal depth) decompression degassing of basaltic intrusions in Iceland
results in CO2 and S fluxes of 330–5060 and 6–210 kt/yr, respectively, which is sufficient to account for the
estimated CO2 flux of Icelandic VHSs (3365–6730 kt/yr), but not the VHS S flux (220–440 kt/yr). Secondary,
crystallization-driven degassing from maturing intrusions and leaching of crustal rocks are suggested as additional
sources of S. Only a minor proportion of the mantle flux of Cl is channeled via VHSs whereas the H2O flux
remains poorly constrained, because magmatic signals in Icelandic VHSs are masked by a dominant shallow
groundwater component of meteoric water origin. These results suggest that the bulk of the mantle CO2 and S
flux to the atmosphere in Iceland is supplied by intrusive, not eruptive magmatism, and is largely vented via
hydrothermal fields.Published107776OSV2: Complessità dei processi vulcanici: approcci multidisciplinari e multiparametriciJCR Journa
Spatiotemporal Evolution of Ground Subsidence and Extensional Basin Bedrock Organization: An Application of Multitemporal Multi-Satellite SAR Interferometry
No full textSince the early 1990s, the European (ESA) and Italian (ASI) space agencies have managed and distributed a huge amount of satellite-recorded SAR data to the research community and private industries. Moreover, the availability of advanced cloud computing services implementing different multi-temporal SAR interferometry techniques allows the generation of deformation time series from massive SAR images. We exploit the information provided by a large PS dataset to determine the temporal trend of ground deformation and the relative deformation rate with millimetric accuracy to analyze the spatial and temporal distribution of land subsidence induced by water pumping from a deep confined aquifer in the Northern Valle Umbra Basin (Central Italy), exploiting 24 years of Permanent Scatterers—interferometric SAR data archives. The SAR images were acquired between 1992 and 2016 by satellites ERS1/2 and ENVISAT, the Sentinel 1 ESA missions and the COSMO-SkyMed ASI mission. We observed ground velocities and deformation geometries between 1992 and 2016, with displacements of more than 70 cm and velocities of up to 55 mm/yr. The results suggest that the shape and position of the surface ground displacement are controlled by the fault activity hidden under the valley deposits.Published1052T. Deformazione crostale attivaJCR Journa
The SAVEMEDCOASTS-2 webGIS: The Online Platform for Relative Sea Level Rise and Storm Surge Scenarios up to 2100 for the Mediterranean Coasts
No full textHere we show the SAVEMEDCOASTS-2 web-based geographic information system (webGIS)
that supports land planners and decision makers in considering the ongoing impacts of Relative
Sea Level Rise (RSLR) when formulating and prioritizing climate-resilient adaptive pathways for the
Mediterranean coasts. The webGIS was developed within the framework of the SAVEMEDCOASTS
and SAVEMEDCOASTS-2 projects, funded by the European Union, which respond to the need to
protect people and assets from natural disasters along the Mediterranean coasts that are vulnerable
to the combined effects of Sea Level Rise (SLR) and Vertical Land Movements (VLM). The geospatial
data include available or new high-resolution Digital Terrain Models (DTM), bathymetric data, rates
of VLM, and multi-temporal coastal flooding scenarios for 2030, 2050, and 2100 with respect to
2021, as a consequence of RSLR. The scenarios are derived from the 5th Assessment Report (AR5)
provided by the Intergovernmental Panel on Climate Change (IPCC) and encompass different Representative
Concentration Pathways (RCP2.6 and RCP8.5) for climate projections. The webGIS reports
RSLR scenarios that incorporate the temporary contribution of both the highest astronomical tides
(HAT) and storm surges (SS), which intensify risks to the coastal infrastructure, local community,
and environment.Published2071OSA4: Ambiente marino, fascia costiera ed Oceanografia operativaJCR Journa
Integrated Access to Multidisciplinary Data Through Semantically Interoperable Services in a Metadata-Driven Platform for Solid Earth Science
No full textThe ability to use data produced by different sources (social networks, governments, weather sensors etc.) is widely recognized as a key to capitalize the value of data. In the scientific field, such usage may incredibly boost the innovation and foster new discoveries. However, one of the main hurdles is currently represented by the difficulties in achieving the required interoperability to provide integrated access to multi-disciplinary data. The current work presents a metadata-driven approach that uses in a combined way metadata, semantics, and services as key components for providing integrated access to heterogeneous data sources. The integration occurs within a central data integration system, which is driven by a rich metadata catalogue and that can present the data provided by the different data sources in a harmonised way to the end user, by means of RESTful APIs. A real application demonstrating metadata-driven semantic and service interoperability for achieving homogeneous access to multi-disciplinary heterogeneous data sources is illustrated in the case of EPOS, a Research Infrastructure for Solid Earth Science. The advantages in terms of ease of maintenance, of flexibility in plugging different standard without perturbating communities’ long-lasting technical practices, and of ability to track provenance are discussed. Future work for providing open-source implementation of a system built following the proposed approach is also envisaged.Published235–247OST5 Verso un nuovo Monitoraggi
Deterministic and stochastic chaos characterize laboratory earthquakes
No full textWe analyze frictional motion for a laboratory fault as it passes through the stability transition from stable sliding to unstable motion. We study frictional stick-slip events, which are the lab equivalent of earthquakes, via dynamical system tools in order to retrieve information on the underlying dynamics and to assess whether there are dynamical changes associated with the transition from stable to unstable motion. We find that the lab seismic cycles characteristics of a low-dimensional system with average dimension similar to that of natural slow earthquakes (5). We also investigate local properties of the attractor and find maximum instantaneous dimension 10, indicating that some regions of the phase space require a high number of degrees of freedom (dofs). Our analysis does not preclude deterministic chaos, but the lab seismic cycle is best explained by a random attractor based on rate- and state-dependent friction whose dynamics is stochastically perturbed.
We find that minimal variations of 0.05\% of the shear and normal stresses applied to the experimental fault influence the large-scale dynamics and the recurrence time of labquakes. While complicated motion including period doubling is observed near the stability transition, even in the fully unstable regime we do not observe truly periodic behavior. Friction's nonlinear nature amplifies small scale perturbations, reducing the predictability of the otherwise periodic macroscopic dynamics. As applied to tectonic faults, our results imply that even small stress field fluctuations (150 kPa) can induce coefficient of variations in earthquake repeat time of a few percent. Moreover, these perturbations can drive an otherwise fast-slipping fault, close to the critical stability condition, into a mixed behavior involving slow and fast ruptures.Published117995OST4 Descrizione in tempo reale del terremoto, del maremoto, loro predicibilità e impattoJCR Journa
The Premodern Descriptive Earthquake Catalogs of von Hoff (1840–1841), Perrey (1845–1850), and Mallet (1853–1855) Under a Magnifying Glass
No full textThe global premodern descriptive catalogs of von Hoff (1840–1841), Perrey (1845–1850), and Mallet (1853–1855), all covering the period from Antiquity to 1842, have been used to populate the preinstrumental section of parametric catalogs since the late 1960s. The earthquake lists of these three authors have been individually analyzed to compile a comprehensive inventory of the sources on which they relied. Conversely to previous analyses and uses that were focused—primarily if not exclusively—on their seismological content, both in the compilation of the inventory and in this article the hundreds of items supplying earthquake records are in the foreground. After having merged these three sets of sources and having obtained a comprehensive list of about 5000 earthquakes and two times more source entries, similarities and differences are evidenced. This comprehensive analysis is meant to catch and explain how the preference given to one source among many available may have affected the interpretation of the collected records and influenced the accuracy and reliability of the earthquake lists by von Hoff, Perrey, and Mallet, and consequently of their contribution to the construction of the global modern parametric earthquake catalogs.Published2456-2468OST2 Deformazione e Hazard sismico e da maremotoJCR Journa
Editorial: Near-earth electromagnetic environment and natural hazards disturbances
No full textThroughout history, human communities have faced consistent threats from natural hazards like earthquakes, volcanic eruptions, and tsunamis. Yet, scientists strive to understand the process behind hazard formation and to predict their occurrences. Since the 1980s, space technology has allowed satellites to capture abnormal electromagnetic (EM) emissions, plasma density irregularities, and energetic particle precipitations near seismic fault zones, volcanic belts, and tsunami-prone coasts. Extensive efforts have been dedicated to rock-rupture processing experiments and ground-space comparative studies. EM precursors have shown promising potential for short-term earthquake prediction. In 2004, France launched the DEMETER satellite, operational until 2010, followed by China’s China Seismo-Electromagnetic Satellite (CSES) in February 2018, focusing on earthquake monitoring from space.
This Research Topic serves two main purposes. Firstly, it validates and calibrates data from ground-based instruments and satellite platforms to explore the space’s EM environment including the EM field, plasma parameters, energetic particle flux, and distributions. Secondly, it emphasizes cross-disciplinary studies of natural hazard monitoring, including earthquakes, volcanoes, etcetera. By combining modeling and observation, the goal is to develop innovative methodologies for studying natural hazards and the interconnected mechanisms of the Lithosphere-Atmosphere-Ionosphere system.Published1307941OST4 Descrizione in tempo reale del terremoto, del maremoto, loro predicibilità e impattoJCR Journa
Buried Alive: Imaging the 9 November 2022, Mw 5.5 Earthquake Source on the Offshore Adriatic Blind Thrust Front of the Northern Apennines (Italy)
No full textThe prompt identification of faults responsible for moderate-to-large earthquakes is fundamental for understanding the likelihood of further, potentially damaging events. This is increasingly challenging when the activated fault is an offshore buried thrust, where neither coseismic surface ruptures nor GPS/InSAR deformation data are available after an earthquake. We show that on 9 November 2022, an Mw 5.5 earthquake offshore Pesaro ruptured a portion of the buried Northern Apennines thrust front (the Cornelia thrust system [CTS]). By post-processing and interpreting the seismic reflection profiles crossing this thrust system, we determined that the activated fault (CTS) is an arcuate 30-km-long, NW-SE striking, SW dipping thrust and that older structures at its footwall possibly influenced its position and geometry. The activation of adjacent segments of the thrust system is a plausible scenario that deserves to be further investigated to understand the full earthquake potential of this offshore seismogenic source.Publishede2022GL1022994T. Sismicità dell'Italia5T. Sismologia, geofisica e geologia per l'ingegneria sismica2TR. Ricostruzione e modellazione della struttura crostale2IT. Laboratori analitici e sperimentaliJCR Journa
Volcanic Emissions, Plume Dispersion, and Downwind Radiative Impacts Following Mount Etna Series of Eruptions of February 21–26, 2021
No full textDuring the extended activity of Mount Etna volcano in February–April 2021, three distinct
paroxysmal events took place from February 21 to 26, which were associated with a very uncommon transport
of the injected upper-tropospheric plumes toward the north. Using a synergy of observations and modeling,
we characterized the emissions and three-dimensional dispersion for these three plumes, monitored their
downwind distribution and optical properties, and estimated their radiative impacts at selected locations. With
a satellite-based source inversion, we estimate the emitted sulfur dioxide (SO2) mass at an integrated value of
55 kt and plumes injections at up to 12 km altitudes, which qualifies this series as an extreme event for Mount
Etna. Then, we combine Lagrangian dispersion modeling, initialized with measured temporally resolved
SO2 emission fluxes and altitudes, with satellite observations to track the dispersion of the three individual
plumes. The transport toward the north allowed the height-resolved downwind monitoring of the plumes
at selected observatories in France, Italy, and Israel, using LiDARs and photometric aerosol observations.
Volcanic-specific aerosol optical depths (AODs) in the visible spectral range ranging from about 0.004 to 0.03
and local daily average shortwave radiative forcing (RF) ranging from about −0.2 to −1.2 W m −2 (at the top of
atmosphere) and from about −0.2 to −3.0 W m −2 (at the surface) are found. The composition (possible presence
of ash), AOD, and RF of the plume have a large inter-plume and intra-plume variability and thus depend
strongly on the position of the sampled section of the plumes.Publishede2021JD0359747A. Geofisica per il monitoraggio ambientaleJCR Journa