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Impact of the Earthquake Rupture on Ground-Motion Variability of the 24 August 2016 M w 6.2 Amatrice, Italy, Earthquake
No full textThe devastating 24 August 2016 M w 6.2 earthquake that struck Amatrice, Italy, marked the beginning of a prolonged seismic sequence dominated by three subsequent M w ≥ 6.0 events in the central Apennines region. The earthquake destroyed Amatrice's historic center, claiming the lives of 299 individuals and causing widespread damage in the neighboring villages. The severity of the ground shaking, with a recorded maximum acceleration of 850 cm= s 2 on the east-west component at the Amatrice station, was far greater than the predicted acceleration based on the Italian ground-motion model (GMM). As pointed out by several investigations, the observed ground-motion amplitude and its spatial variability during the earthquake can be linked to specific rupture characteristics, including slip distribution and rupture directivity effects revealed by the observed data (Tinti et al., 2016; Pischiutta et al., 2021). In this study, we conducted physics-based 3D numerical simulations of ground motion for the Amatrice earthquake for frequencies up to 3 Hz. We employed a series of kinematic rupture models and a well-constrained local 3D velocity model incorporating surface topography. The kinematic rupture realizations were generated using multiscale hybrid and fully stochastic models, following the technique proposed by Graves and Pitarka (2016). We focused on assessing the sensitivity of near-fault ground-motion amplitudes to earthquake rupture characteristics, in particular, the spatial slip pattern. To evaluate the quality of our simulations, we employed goodness-of-fit measurements performed in comparisons of simulated and recorded ground motions. The simulated ground motions compare well with the recorded data and predictions from GMMs for Italy, ITA18 (Lanzano et al., 2019). However, we found that the simulated interevent ground-motion variability (randomness in the source process) of peak ground velocity, σ (PGV) is higher than the constant σ (PGV) predicted by conventional GMMs. Our simulations using several rupture scenarios demonstrate that the near-fault groundmotion amplification pattern is directly related to the slip distribution pattern. KEY POINTS • The near-fault ground-motion amplification pattern is related to the size and distribution of the slip. • The rupture directivity is controlled by location of the rupture initiation relative to the large slip patches. • Peak ground velocity interevent variability is distance dependent and higher at shorter distances than that of constant ground-motion models.PublishedJCR Journa
A journey to learn about our planet among air, water, earth and fire: a selection of articles from the INGVterremoti blog
No full textPublishe
How artificial intelligence can enhance monitoring of volcanoes from space
No full textThe ability to collect and analyze satellite data in near real-time (NRT) is fundamental for monitoring volcanic hazards and identifying the needed mitigation actions. This capability depends mainly on the availability of satellite data, which can range from a few minutes (SEVIRI, MODIS) to several days (MSI, OLI). Volcanology has embraced artificial intelligence (AI), incorporating both Machine Learning (ML) and Deep Learning (DL), allowing computers to learn from historical data and build a knowledge base of volcanic processes. An AI-based platform has been developed for NRT monitoring of volcanic activity, utilizing satellite imagery and offline analysis. ML and DL algorithms automatically evaluate volcano status from extensive multi-spectral satellite data flows. Built-in modules work together towards a common goal and are activated based on AI logic. These modules are adept at diverse tasks, from forecasting eruption initiation to quantifying erupted products using satellite thermal measurements. This platform represents an unprecedented convergence between technological innovation and the scientific community’s experience overcoming limitations of traditional approaches by inferring knowledge from large amounts of heterogeneous satellite data. It enables informed, timely, and sophisticated management of volcanic activity, significantly contributing to enhancing safety measures and minimizing the impact of volcanic events on communities and infrastructure.Published308OST5 Verso un nuovo MonitoraggioJCR Journa
MVC_2023
No full textL'Istituto Nazionale di Geofisica e Vulcanologia (INGV) è componente del Servizio Nazionale di Protezione Civile, ex articolo 6 della legge 24 febbraio 1992 n. 225 ed è Centro di Competenza per i fenomeni sismici, vulcanici e i maremoti per il Dipartimento della Protezione Civile Nazionale (DPC). L’Osservatorio Vesuviano, Sezione di Napoli dell’INGV, ha nei suoi compiti il monitoraggio e la sorveglianza H24/7 delle aree vulcaniche attive campane (Vesuvio, Campi Flegrei e Ischia). Tali attività sono disciplinate dall’Accordo-Quadro (AQ) sottoscritto tra il DPC e l’INGV per il periodo 2022-2025 e sono dettagliate nell’Allegato Tecnico del suddetto AQ. Il presente Rapporto sul Monitoraggio dei Vulcani Campani rappresenta l’attività svolta dall’Osservatorio Vesuviano e dalle altre Sezioni INGV impegnate nel monitoraggio dell’area vulcanica campana nel 2023.Istituto Nazionale di Geofisica e Vulcanologia
Dipartimento della Protezione CivileUnpublishedOSV1: Verso la previsione dei fenomeni vulcanici pericolosiOSV2: Complessità dei processi vulcanici: approcci multidisciplinari e multiparametriciOSV3: Sviluppo di nuovi sistemi osservazionali e di analisi ad alta sensibilitàOSV4: Preparazione alle crisi vulcanich
On floating point precision in computational fluid dynamics using OpenFOAM
No full textThanks to the computational power of modern cluster machines, numerical simulations can provide, with an unprecedented level of details, new insights into fluid mechanics. However, taking full advantage of this hardware remains challenging since data communication remains a significant bottleneck to reaching peak performances. Reducing floating point precision is a simple and effective way to reduce data movement and improve the computational speed of most applications. Nevertheless, special care needs to be taken to ensure the quality and convergence of computed solutions, especially when dealing with complex fluid simulations. In this work, we analyse the impact of reduced (single and mixed compared to double) precision on computational performance and accuracy for computational fluid dynamics. Using the open source library OpenFOAM, we consider incompressible, compressible, and multiphase fluid solvers for testing on relevant benchmarks for flows in the laminar and turbulent regime and in the presence of shock waves. Computational gain and changes in the scalability of applications in reduced precision are also discussed. In particular, an ad hoc theoretical model for the strong scaling allows us to interpret and understand the observed behaviours, as a function of floating point precision and hardware specifics. Finally, we show how reduced precision can significantly speed up a hybrid CPU–GPU implementation, made available to OpenFOAM end-users recently, that simply relies on a GPU linear algebra solver developed by hardware vendors.Published1-16OSV1: Verso la previsione dei fenomeni vulcanici pericolosiJCR Journa
Seismotectonic Setting of the Andes along the Nazca Ridge Subduction Transect: New Insights from Thermal and Finite Element Modelling
No full textThis article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BYPublished257OST1 Alla ricerca dei Motori GeodinamiciJCR Journa
Dynamics of magmatic intrusion: what can we learn from the comparison of analog and numerical models?
No full textThis study investigates the dynamics of magmatic intrusions based on the joint analysis of analog and numerical models.By injecting different fluids from the bottom of a solidified gelatin block, we simulate the propagation of magmatic intrusions through the crust and record their shapes, trajectories, and velocity as they rise towards the surface. Additionally, we make use of a 2D fluid-filled crack propagation model constrained by our experimental observations. The numerical simulations demonstrate that our viscous fluid-filled crack experiments, conducted with silicon-oil injections, propagate in the same regime as typical basaltic intrusions. The comparison between analog and numerical results allow us to define the domain of validity of the numerical model and its limit of applicability. This study provides new insights into the processes that control the propagation of magmatic intrusions and our ability to reproduce them using analog and numerical models.Published67-87OSV1: Verso la previsione dei fenomeni vulcanici pericolosiN/A or not JC
Insights Into Venus' Crustal Plateaus From Dyke Trajectories Below Craters
No full textOn Venus, radar observations of the surface have highlighted two categories of craters: bright-floored, interpreted as pristine, and dark-floored, interpreted as being partially filled by lava. While volcanic resurfacing occurs within and outside craters in the plains, it seems mainly concentrated within the interior of dark-floored craters in the crustal plateaus, suggesting that the magma is negatively buoyant there. Indeed, crater unloading may facilitate vertical ascent of a negatively buoyant magma by decompressing the underlying crust. However, the crater topography also generates a shear stress which would tend to horizontalize the vertical propagation of a dyke. We use numerical simulations of magma ascent in an axisymmetric crater stress field to demonstrate that, depending on the crust thickness and the magma-crust density contrast, a negatively buoyant magma can indeed erupt only in the crater interior while remaining stored in the crust elsewhere. In particular, we identify four different behaviors depending on if and where a magma-filled crack ascending below a crater reaches the surface. We draw a regime diagram as a function of two characteristic dimensionless numbers. For eruption to occur only in the crater interior requires a crust thinner than 45 km and a limited range of magma-crust density contrasts, between 40 and 280 kg m−3 for crust thicknesses between 20 and 45 km, the permissible range decreasing for increasing crustal thicknesses. These results suggest that the crustal plateaus may not be particularly thick and could be slightly differentiated, but probably not very felsic.Publishede2023JE008189OSV2: Complessità dei processi vulcanici: approcci multidisciplinari e multiparametriciJCR Journa
Pre-Earthquake Oscillating and Accelerating Patterns in the Lithosphere–Atmosphere–Ionosphere Coupling (LAIC) before the 2022 Luding (China) Ms6.8 Earthquake
No full textThe coupling processes among the lithosphere, atmosphere, and ionosphere (LAI) during the earthquake preparation phase are still an open scientific debate. Comprehensive LAI coupling effects around the 2022 Ms6.8 Luding earthquake in China are investigated with a multi-parameter and multi-layer approach, including the b-value, revised accelerated moment release, Earth resistivity, ELF magnetic field emissions, atmospheric electric field, surface temperature, foF2 from ionosonde, GNSS TEC, Ne and magnetic field from CSES and Swarm satellites, and energetic electrons from CSES and NOAA satellites. It is found that the anomalies start from the lithospheric parameters as Earth resistivity and b-values 1–2 years before to reflect the local stress loading in the seismic region, then the ionospheric and atmospheric disturbances occur and accelerate −50 days before and −15 days before, and finally the electrons precipitate a few days before. The simultaneous perturbations in LAI illustrate the thermodynamic coupling channel, such as on 24 August, −12 days before. Meanwhile, the abundant developed ionospheric anomalies without atmospheric disturbances demonstrate the electromagnetic coupling way from the lithosphere to the ionosphere directly. Finally, the results demonstrate a two-way model of LAIC: one way is characterized by a slow chain of processes, of thermodynamic nature, starting from the ground and proceeding to the above atmosphere and ionosphere, showing an exponential trend in the cumulative number of anomalies; the second way is characterized by oscillating electromagnetic coupling between the lithosphere and ionosphere, showing intermittent fluctuations in the corresponding cumulative number of anomalies.Published2381OST4 Descrizione in tempo reale del terremoto, del maremoto, loro predicibilità e impattoJCR Journa
Multidisciplinary high resolution Geophysical Imaging of Pantano Ripa Rossa Segment of the Irpinia Fault (Southern Italy)
No full textThe Irpinia Fault, also known as the Monte Marzano Fault System, located in the Southern Apennines (Italy), is one of the most seismically active structures in the Mediterranean. It is the source of the 1980, Ms 6.9, multi-segment rupture earthquake that caused significant damage and nearly 3,000 casualties. Paleoseismological surveys indicate that this structure has generated at least four Mw ~ 7 surface-rupturing earthquakes in the past 2 ka. This paper presents a comprehensive, high-resolution geophysical investigation focused on the southernmost fault segment of the Monte Marzano Fault System, i.e., the Pantano-Ripa Rossa Fault, outcropping within the Pantano di San Gregorio Magno intramontane basin. The project, named TEst Site IRpinia fAult (TESIRA), was supported by the University of Napoli Federico II to study the near-surface structure of this intra-basin fault splay that repeatedly ruptured co-seismically in the past thousands of years. Our imaging approach included 2D and 3D electrical and seismic surveys, gravimetry, 3D FullWaver electrical tomography, drone-borne GPR and magnetic surveys, and CO2 soil flux assessment across the surface rupture. This multidisciplinary investigation improved our understanding of the basin shallow structure, providing an image of a rather complex subsurface fault and basin geometry. Seismic data suggest that fault activity at the Pantano segment of MMFS is characterized by a near-surface cumulative displacement greater than previous estimations, calling into question earlier assumptions about the timing of its activation. Despite some challenges with our drone-mounted survey equipment, the integrated dataset provides a comprehensive and reliable image of the subsurface structure. This work demonstrates the utility of developing an integrated approach at high-resolution geophysical imaging and interpretation of fault zones with weak morphological expressions.Published26891OST3 Vicino alla fagliaJCR Journa