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The Adriatic Thrust Fault of the 2021 Seismic Sequence Estimated from Accurate Earthquake Locations Using sP Depth Phases
No full textAn earthquake sequence occurred in the Central Adriatic region during March–June 2021.
This sequence started on 27 March with a mainshock of moment magnitude (Mw) 5.2 occurring at 13:47 coordinated universal time (UTC). No foreshock was observed before this
mainshock. The sequence lasted approximately three months, until the end of June
2021. Approximately 200 seismic events were recorded by the regional seismic network
during this time, including four M ≥ 4.0 earthquakes. The 27 March 2021 earthquake
was one of the strongest instrumentally recorded events in the area bounded approximately by the Ancona–Zadar line to the north and the Gargano–Dubrovnik line to the
south. The mainshock originated at a focal depth of 9.9 km. The seismicity spread from
the mainshock up-dip and down-dip along a northeast-dipping plane. Here, we investigate
the geometry of the fault activated by this seismic sequence by using sP depth phases. We
aim to significantly reduce the large uncertainties associated with the hypocentral locations of offshore earthquakes beneath the Adriatic Sea—an area that plays a fundamental
role in the geodynamics of the Mediterranean. These refined earthquake locations also
allow us to make inferences with regards to the seismotectonic context responsible for
the analyzed seismicity, thus identifying a structure (here referred to as the MidAdriatic fault) consisting of a northwest–southeast-striking thrust fault with a ∼ 35° northeast-dipping plane. The use of depth-phase arrival times to constrain off-network event
locations is of particular interest in Italy due to both the peculiar shape of the peninsula
and the extreme scarcity of seafloor stations, the cost and management of which are very
expensive and complex. Here, we present the first attempt to apply this off-network locating technique to the Italian offshore seismicity research with the aim of improving hazard
estimations in these hard-to-monitor regions.Published480–493OST3 Vicino alla fagliaJCR Journa
Sensitivity analysis of polar orbiter motion to lunar viscoelastic tidal deformation
No full textWe investigate the impact of viscoelastic tidal deformation of the Moon on the motion of a polar orbiter. The dissipative effects in the Moon’s interior, i.e., tidal phase lags, are modeled as Fourier series sampled at given frequencies associated with linear combinations of Delaunay arguments, the fundamental parameters describing the lunar motion around the Earth and the Sun. We implement the tidal model to evaluate the temporal lunar gravity field and the induced perturbation on the orbiter. We validate the numerical scheme via a frequency analysis of the perturbed orbital motion. We show that, in the case of the Lunar Reconnaissance Orbiter at a low altitude of less than 200 km, the main lunar tides and hence the potential Love numbers around the monthly and some multiple frequencies are dynamically separable. The omission of those effects in practice introduces a position error at the level of a few decimeters within 10 days.Published161T. Struttura della TerraJCR Journa
Remnants of a Young Monogenetic Volcanic Field and the Fragile Balance of Anthropogenic Interaction
No full textThe rapid development of Auckland City in New Zealand from an initial rural settlement to a global urban hub produced a characteristic footprint on the Auckland Volcanic Field (AVF). This process was facilitated by increased anthropogenic activity that has resulted in the deterioration and destruction of many volcanic landforms and caused severe archaeological, cultural, geological and educational losses in an alarmingly short timescale. The AVF has 53 volcanic centres, and of these, 17% are classified as intact, 28% are partially intact, 30% are partially destroyed, and 25% are destroyed (including 13% that have no trace left). Based on surface area, approximately 40% of volcanic deposits in the AVF have been lost. The most common causes for impacts are public land use, quarrying and urban development. Regardless, there is significant potential to be found in the balance between the losses and gains of anthropogenic impacts on volcanic landforms. In the AVF and
worldwide, geological studies have often been assisted by the presence of outcrops created by quarrying, mining, transport infrastructure and other modifications of volcanic landforms. Areas of significant volcanic geoheritage worldwide are often linked with these impacted volcanoes, and the information gained from these geoheritage areas assists in the management of geodiversity and geoeducation. Several volcanic centres are currently at risk of further destruction in the near future (Crater Hill, Waitomokia, Maugataketake, Kohuroa, Three Kings, St Heliers and McLaughlins Mt) and should be prioritised for any possible research before it is too late. We propose that a geological assessment should be a requirement before and, if possible, during any land development on or near a volcanic landform. Allowing access to scientists through the course of development in areas with volcanic landforms would, in turn, aid public and governing bodies in decision-making for the
future of the city and its volcanoes in terms of increased knowledge of volcanic mechanisms of the AVF and awareness of the potential associated hazards.Published131OSV2: Complessità dei processi vulcanici: approcci multidisciplinari e multiparametriciJCR Journa
Editorial: Source and effects of light to moderate magnitude earthquakes – Volume II
No full textNo abstractPublished1164767JCR Journa
A Multi-Sensor Satellite Approach to Characterize the Volcanic Deposits Emitted during Etna’s Lava Fountaining: The 2020–2022 Study Case
No full textBetween December 2020 and February 2022, the South East Crater of Etna has been the source of numerous eruptions, mostly characterized by the emission of lava fountains, pyroclastic material and short-lasting lava flows. Here we estimate the volume and distribution of the lava deposits by elaborating multi-source satellite imagery. SEVIRI data have been elaborated using CL-HOTSAT to estimate the lava volume emitted during each event and calculate the cumulative volume; Pléiades and WorldView-1 data have been used to derive Digital Surface Models, whose differences provide thickness distributions and hence volumes of the volcanic deposits. We find a good agreement, with the total average lava volume obtained by SEVIRI reaching 73.2 × 106 m3 and the one from optical data amounting to 67.7 × 106 m3. This proves the robustness of both techniques and the accuracy of the volume estimates, which provide important information on the lava flooding history and evolution of the volcano.This work was supported by the INGV project Pianeta Dinamico (CUP D53J19000170001) funded by MIUR (“Fondo finalizzato al rilancio degli investimenti delle amministrazioni centrali dello Stato e allo sviluppo del Paese,” legge 145/2018), Tema 8—PANACEA, Scientific Responsibility: A.C.). The research was also funded by “TUNE—Effusion rate estimates at Etna and Stromboli: constraints imposed by a variety of satellite remote sensing data” (Bando di Ricerca Libera 2019 of INGV; Scientific Responsibility: G.G.). This research was also supported 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; Scientific Responsibility: S.C.).Published9165V. Processi eruttivi e post-eruttiviJCR Journa
Relative Sea-Level Rise Projections and Flooding Scenarios for 2150 CE for the Island of Ustica (Southern Tyrrhenian Sea, Italy)
No full textThe island of Ustica (Italy) is constantly exposed to the effects of sea-level rise, which is threatening its coastal zone. With the aim of assessing the sea levels that are anticipated by 2150 CE under the climatic projections shown in the AR6 report from the IPCC, a detailed evaluation of potential coastal flooding under different climatic scenarios and the ongoing land subsidence has been carried out for three coastal zones. Scenarios are based on the determination of the current coastline position, a high-resolution digital terrain and marine model, and the SSP1-2.6, SSP3-7.0, and SSP5-8.5 climatic projections. Relative sea-level rise projections allowed the mapping of the potential inundated surfaces for 2030, 2050, 2100, and 2150. The results show rising sea levels for 2150, ranging from a minimum of 66 ± 40 cm (IPCC AR6 SSP2.6 scenario) to a maximum of 128 ± 52 cm (IPCC AR6 SSP8.5 scenario). In such conditions, considering the SSP8.5 scenario during storm surges with return times (RTs) of 1 and 100 years, the expected maximum wave run-up along the island may vary from 3 m (RT = 1) to 14 m (RT = 100), according to the coastal morphology. Our results show that adaptation and mitigation actions are required to protect the touristic and harbor installations of the island.Published2013OSA2: Evoluzione climatica: effetti e loro mitigazioneJCR Journa
Seismic anisotropy and shear-wave splitting: Achievements and perspectives: foreword
No full textThis special issue of Annals of Geophysics “Seismic anisotropy and shear-wave splitting: Achievements and perspectives” originates from a session (S10) of the 37th General assembly of the European Seismological commission ESC 2021 Conference which was planned to take place on 21 September 2021, in Corfu Greece, but due to the Covid19 pandemic was Virtual.
The main theme of the session and of this special issue was the crucial role of seismic anisotropy in investigating the Earth’s interior from the upper crust to the inner core. Shear-wave splitting, one of the most effective ways to study seismic anisotropy, can identify the properties and the geodynamics of the upper mantle, and identify the presence of fluid-saturated microcracks, oriented according to the stress regime, in the upper crust. Azimuthal anisotropy and radial anisotropy can be assessed from earthquake or ambient noise recordings to detect the seismic layered features and to rebuild the 3D seismic structurePublishedSE2041T. Struttura della TerraJCR Journa
Characterization of the carbonate rocks of the Calcari di Cagliari Formation using a combined petrographic, geomatic and geophysical approach.
No full textThe methods and the tools aimed at characterizing and analysing the carbonate materials used in
the historic built heritage often follow different ways according to the different branches of
applied research involved in the knowledge process. In this framework, the 3D digital models both
of in situ architectural elements and of significative samples of rocks used as building materials
can play an important role in relating different data and disciplines aimed at the prevention and
conservation of the Cultural Heritage. Although the 3D geomatic and geophysical digital models
represent privileged tools of the diagnostic analysis, they must be supported by the knowledge of
the textural characteristics of the rocks under investigation with petrographic analyses. In order to
study the stone materials heavily used in the historic built heritage and analyse their vulnerability
to the conditions in their environment, it can be beneficial to study appropriately prepared
samples and make as many measurements as necessary with different techniques. Moreover,
some analyses are destructive and there is a limit to the number of samples that can be sacrificed.
For this reason, in the analysis of rock samples, non-destructive techniques are constantly being
improved. In this study, using a suitably implemented integrated methodology we analysed in
detail samples of the carbonate rocks of the Calcari di Cagliari formation represented by Pietra
Cantone, Tramezzario and Pietra Forte lithologies, mainly used in the past as construction
materials for the buildings of the Historical Centre of Cagliari (Italy). Our methodology is
represented by an integration of the geomatic survey carried out by structure-from-motion (SfM)
digital close-range photogrammetry and the seismic tomography normally used for the in situ
inspection adapted to laboratory tests on samples of the above lithologies using ultrasonic
frequency signals. The rigorous metric of the geomatic 3D models was used to implement the
ultrasonic survey by which internal characteristics and physical properties of the studied material
are detected thanks to the spatial variations of the longitudinal velocity obtained after the
tomographic inversion. The geomatic and geophysical data were complemented by an accurate
analysis of the above carbonate materials by optical and scanning electron microscopy in order to
detect their textural characteristics and especially the nature and distribution of their porosity. The microscopy analyses were integrated by mercury intrusion porosimetry (MIP) to obtain further
information on the pore network, particularly on the effective porosity, pores-throat
diameters/radii, permeability and tortuosity of the investigated materials. All the above
parameters were found to affect the geomatic and geophysical behaviour of the carbonate
materials. The integration of the multi-technique data produced in this study contributes to better
understand the interaction between the investigated materials and the environment.PublishedVienna, AustriaOST2 Deformazione e Hazard sismico e da maremot
Effective processing pipeline PACE 2.0 for enhancing chest x‑ray contrast and diagnostic interpretability
No full textPreprocessing is an essential task for the correct analysis of digital medical images. In particular,
X-ray imaging might contain artifacts, low contrast, diffractions or intensity inhomogeneities.
Recently, we have developed a procedure named PACE that is able to improve chest X-ray (CXR)
images including the enforcement of clinical evaluation of pneumonia originated by COVID-19. At
the clinical benchmark state of this tool, there have been found some peculiar conditions causing a
reduction of details over large bright regions (as in ground-glass opacities and in pleural effusions in
bedridden patients) and resulting in oversaturated areas. Here, we have significantly improved the
overall performance of the original approach including the results in those specific cases by developing
PACE2.0. It combines 2D image decomposition, non-local means denoising, gamma correction, and
recursive algorithms to improve image quality. The tool has been evaluated using three metrics:
contrast improvement index, information entropy, and effective measure of enhancement, resulting
in an average increase of 35% in CII, 7.5% in ENT, 95.6% in EME and 13% in BRISQUE against original
radiographies. Additionally, the enhanced images were fed to a pre-trained DenseNet-121 model for
transfer learning, resulting in an increase in classification accuracy from 80 to 94% and recall from
89 to 97%, respectively. These improvements led to a potential enhancement of the interpretability
of lesion detection in CXRs. PACE2.0 has the potential to become a valuable tool for clinical decision
support and could help healthcare professionals detect pneumonia more accurately.Published22471OSA1: Variazioni del campo magnetico terrestre, imaging crostale e sicurezza del territorioJCR Journa
Marine litter tracking system: a case study with open-source technology and a citizen science-based approach
No full textIt is well established that rivers are amongst the most important carriers of the plastic pollution found in the oceans. However, the main processes contributing to plastic and debris fate through riparian systems is still poorly known and understood. The Marine Litter Drifter project from the Arno River aims at using modern consumer software and hardware technologies to track the trajectories and evolution at sea of real Anthropogenic Marine Debris (AMD) from rivers, with a specific focus on the Arno River, in Italy. Innovative and low cost “Marine Litter Trackers” (MLT) were designed, assembled and used in this framework as they are reliable, robust, self-powered and they present almost no maintenance costs. Furthermore, they can be built not only by those trained in the field but also by those with no specific expertise, including high school students, simply by following the instructions.
Several dispersion experiments were successfully conducted using different types of trackers in different seasons and weather conditions. The maximum distance tracked was 2845 km for a period of 94 days. The activity at sea was integrated by lagrangian numerical models supporting the planning of the deployments and the recovery of the drifters. The models, in turn could benefit from the observed tracking data for calibration and validation and serve as tools to study and interpret the processes driving macro plastic displacement at sea. In this presentation we describe this activity and we discuss the dynamics of marine litter (ML) dispersion in the Tyrrhenian Sea on the basis of these integrated monitoring tools, as well as the potential of open-source approaches including the “citizen-science” perspective for both improving Big Data collection and educating/awareness-raising on AMD issues.PublishedVienna, Austria4A. Oceanografia e clim