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Duronia Geomagnetic Observatory 2022
No full textIstituto Nazionale di Geofisica e VulcanologiaPublishedOSA1: Variazioni del campo magnetico terrestre, imaging crostale e sicurezza del territori
Roof covering classification using skysat multispectral imagery
No full textClassification of roof covering in urban areas using aerial imagery is a challenging task. In this work we present a preliminary mapping of roofs using the high-resolution Skysat multispectral images. The classification is performed using a two-stage machine learning approach: the first stage includes a supervised classification for land use, while the second stage includes the classification of terraces and roofs with one or more pitches in those areas previously recognized as edifices. The methodology has been tested to classify the roofs in the north-east part of the Stromboli Island (Sicily, Italy). Our preliminary results are promising and encourage us to pursue further developments as ways to improve accuracy and reliability of the classification.Published260002OSV3: Sviluppo di nuovi sistemi osservazionali e di analisi ad alta sensibilitàN/A or not JC
Seismological temporal patterns at Mefite d’Ansanto CO2 emission field.
No full textMefite d’Ansanto (Italy) is the largest non-volcanic CO2 emission field on the Earth. The isotopic
signature of the CO2 testifies a deep origin of the gases emitted at this site, whose source is
probably the mantle wedge beneath the Apennines along the Tyrrhenian side (Chiodini et al.,
2010). Mefite is located between the Sannio and the Irpinia seismogenic regions, that are
considered among the most active areas of the southern Apennines. The emission site falls at the
northern tip of the Irpinia fault system that is associated with the destructive MS = 6.9, 1980 Irpinia
earthquake. The gas leakage from this zone is linked to active faulting that characterized the area
and determined large historical earthquakes
A temporary acquisition survey close to the Mefite emission field was carried out between 8 June
and 28 September 2020 by using a seismic array, named Array MEfite (AME), composed of seven
short-period stations. We have analyzed the characteristics of the recorded background seismic
noise, e.g., spectral properties, energy temporal pattern (RMS) and polarization (Montalbetti et al.,
1970), and estimated site effects (Nakamura, 1989; http://www.geopsy.org/). The seismological
temporal patterns have been compared with the meteorological parameters, such as temperature
and rainfall, to find possible relationships with exogenous factors. We found a well-defined spatial
pattern for the spectral components above 5 Hz, which appear clearly linked to the emission field
dynamics. On the other hand, the spectral components below 5 Hz result from the overlapping of
multiple sources, of both exogenous, such as anthropogenic and meteorological factors, and
endogenous nature. Application of the Independent Component Analysis (ICA) technique
(Hyvärinen et al., 2001) contributed to discriminate between natural and anthropogenic sources.PublishedVienna, Austria3T. Fisica dei terremoti e Sorgente Sismic
Friction Experiments on Lunar Analog Gouges and Implications for the Mechanism of the Apollo 17 Long Runout Landslide
No full textThe Light Mantle landslide is a hypermobile landslide on the Moon. Apollo 17 astronauts collected a core sample of the top 60 cm of the Light Mantle deposit, which is currently being analyzed as part of the NASA's Apollo Next Generation Sample Analysis program. The origin of its hypermobility remains undetermined, as the proposed mechanisms are difficult to prove because of the lack of theoretical and experimental support and the scarcity of field data related to the internal structures of its deposit. Regardless of the emplacement mechanisms, it has been proposed that localized dynamic frictional weakening is responsible for the early stage instability that leads to catastrophic failure. Here, we conduct friction experiments under vacuum to investigate the viability of dynamic friction weakening in lunar analog anorthosite-bearing gouges (i.e., rock powders). Our results show that localized dynamic friction weakening does not occur in these gouges at loading conditions where, instead, weakening is observed in other materials on Earth. Therefore, possibly other fluidization-related mechanisms contributed to the initiation of the hypermobile Light Mantle landslide. Finally, we describe the microstructures formed in the experiments, including the presence of clast cortex aggregates. Preliminary investigation of the Light Mantle core samples (73001/73002) shows the presence of similar microstructures. Therefore, our microstructural observations will help the analysis and interpretation of the Apollo 17 core samples, as keys to insights about internal processes occurring during the emplacement of the landslide.Publishede2022JE007520OST3 Vicino alla fagliaJCR Journa
Dolostone pulverization induced by coseismic rapid decompression of CO2-rich gas in nature (Matese, Apennines, Italy)
No full textSouth Matese, Apennines, is a hydrothermally and seismically active extensional area characterized by CO2outgassing and Mw≤7.1 earthquakes. There, meters-sized pockets of incohesive pulverized dolostone are hosted within Mesozoic carbonates at the hanging wall of seismically active normal faults. The aim of this paper is to understand the pulverization process. The pulverized dolostone is finely comminuted (down to a few microns), but primary structures, mainly bedding, are preserved. The grain size distribution is similar to that of previously studied pulverized rocks associated with active faults and dissimilar to that of carbonate cataclasites and fault gouges. The pulverized pockets are surrounded by zones (halos), in which the loose grains are cemented, in their original position, by microcrystalline calcite, resulting in a cemented micro-mosaic breccia. Stable isotopes from the cement are compatible with calcite precipitation from rapidly CO2-degassing shallow waters. Comparing our observations with results of laboratory experiments on carbonate pulverization through rapid decompression of pore-hosted CO2, the best explanation for the pulverized dolostone may lie on local accumulations of pressurized CO2-rich gas, suddenly decompressed during earthquakes. The limited permeability of the gas-saturated dolostone must have prevented a prompt escape of the gas from the rock, which was therefore anhydrously pulverized by the rapid expansion of the trapped gas. The sudden decompression must have suctioned bicarbonate-rich groundwaters, from which microcrystalline calcite rapidly precipitated, fossilizing the freshly pulverized dolostone. Calcite precipitation formed an impermeable shield around the pulverized pockets, which, therefore, remained internally uncemented. This process may have occurred over multiple cycles at depths shallower than the CO2subcritical–supercritical boundary (ca. -800m). Although hypothetical, the proposed mechanism is for the first time suggested for an active tectonic environment. The gas rapid decompression could have been triggered by coseismic processes (e.g., dynamic unloading or transient tensile pulses) previously proposed for the formation of other pulverized rocks. The presented case may improve our knowledge of possible chemical-physical processes connected with the subsurface storage of CO2in seismically active areas.Published1179969T. Geochimica dei fluidi applicata allo studio e al monitoraggio di aree sismicheJCR Journa
28th September 2018 Mw 7.5 Sulawesi Supershear Earthquake, Indonesia: Ground effects and macroseismic intensity estimation using ESI-2007 scale
No full textThe 28th September 2018 Sulawesi Supershear earthquake (MW 7.5) was one of the deadliest earthquakes in the recent history of Indonesia causing ∼4000 causalities. The earthquake caused a ∼ 177 km long surface rupture along the Palu-Karo fault. Apart from surface rupture, the earthquake caused extensive earthquake environmental effects (EEEs) around the Palu-Donggala area of Central Sulawesi, Indonesia, which includes tsunami, coastal landslide, liquefaction, ground cracks and more than 7300 landslides in hilly areas. Initial post-event analysis and reports assigned a Modified Mercalli Intensity (MMI) of VII to VIII in Palu City and the surrounding area. Building damage and ground effects caused by the earthquake suggested that seismic intensity was understated. Here we applied the EEEs information from field survey data, published reports, and remote sensing tools to determine macroseismic intensity using the Environmental Seismic Intensity (ESI-07) Scale. The ESI-07 intensity derived from the ground effects suggests the maximum intensity of X-XI, which is 3–4° higher than the traditional intensity estimated by the United States Geological Survey (USGS) and the Indonesian Agency for Meteorology, Climatology, and Geophysics (BMKG). ShakeMaps were generated considering the ESI-07 values. The ShakeMap was compared with the instrumentally derived ShakeMap for the Palu earthquake, which proves that the ShakeMap prepared from the instrumental data or structural damage data is underrated. We argue that proper documentation of the EEEs is necessary for such damaging earthquakes for future earthquake hazard mapping and planning in the study area and other earthquakes in Indonesia. In addition, this will help in defining the on-fault and off-fault damage zone towards reducing the seismic risk of the Palu Donggala area.Published107054JCR Journa
Relazione dell’attività 2022 del Gruppo di Lavoro INGVterremoti
No full textIn questo report vengono descritte le attività principali svolte nel 2022
relativamente ai diversi canali web istituzionali e alla piattaforma INGVterremoti, fornendo anche, ove possibile, dati statisticiutili per la valutazione.INGVPublishedOS: Terza mission
Investigation of three-dimensional radiative transfer effects for UV–Vis satellite and ground-based observations of volcanic plumes
No full textWe investigate effects of the three-dimensional (3D) structure of volcanic plumes on the retrieval results of satellite and ground-based UV–Vis observations. For the analysis of such measurements, 1D scenarios are usually assumed (the atmospheric properties only depend on altitude). While 1D assumptions are well suited for the analysis of many atmospheric phenomena, they are usually less appropriate for narrow trace gas plumes. For UV–Vis satellite instruments with large ground pixel sizes like the Global Ozone Monitoring Experiment-2 (GOME-2), the SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY) or the Ozone Monitoring Instrument (OMI), 3D effects are of minor importance, but usually these observations are not sensitive to small volcanic plumes. In contrast, observations of the TROPOspheric Monitoring Instrument (TROPOMI) on board Sentinel-5P have a much smaller ground pixel size (3.5 × 5.5 km2). Thus, on the one hand, TROPOMI can detect much smaller plumes than previous instruments. On the other hand, 3D effects become more important, because the TROPOMI ground pixel size is smaller than the height of the troposphere and also smaller than horizontal atmospheric photon path lengths in the UV–Vis spectral range.
In this study we investigate the following 3D effects using Monte Carlo radiative transfer simulations: (1) the light-mixing effect caused by horizontal photon paths, (2) the saturation effect for strong SO2 absorption, (3) geometric effects related to slant illumination and viewing angles and (4) plume side-effects related to slant illumination angles and photons reaching the sensor from the sides of volcanic plumes. The first two effects especially can lead to a strong and systematic underestimation of the true trace gas content if 1D retrievals are applied (more than 50 % for the light-mixing effect and up to 100 % for the saturation effect). Besides the atmospheric radiative transfer, the saturation effect also affects the spectral retrievals. Geometric effects have a weaker influence on the quantitative analyses but can lead to a spatial smearing of elevated plumes or even to virtual double plumes. Plume side-effects are small for short wavelengths but can become large for longer wavelengths (up to 100 % for slant viewing and illumination angles). For ground-based observations, most of the above-mentioned 3D effects are not important because of the narrow field of view (FOV) and the closer distance between the instrument and the volcanic plume. However, the light-mixing effect shows a similar strong dependence on the horizontal plume extension as for satellite observations and should be taken into account for the analysis of ground-based observations.Published1609–1662OSV3: Sviluppo di nuovi sistemi osservazionali e di analisi ad alta sensibilitàJCR Journa
Ginger
No full textIn this paper, we outline the scientific objectives, the experimental layout, and the collaborations envisaged for the GINGER (Gyroscopes IN GEneral Relativity) project. The GINGER project brings together different scientific disciplines aiming at building an array of Ring Laser Gyroscopes (RLGs), exploiting the Sagnac effect, to measure continuously, with sensitivity better than picorad/s, large bandwidth (ca. 1 kHz), and high dynamic range, the absolute angular rotation rate of the Earth. In the paper, we address the feasibility of the apparatus with respect to the ambitious specifications above, as well as prove how such an apparatus, which will be able to detect strong Earthquakes, very weak geodetic signals, as well as general relativity effects like Lense-Thirring and de Sitter, will help scientific advancements in Theoretical Physics, Geophysics, and Geodesy, among other scientific fields.Published203–234OST1 Alla ricerca dei Motori GeodinamiciJCR Journa
Two-Dimensional Geothermal Model of the Peruvian Andes above the Nazca Ridge Subduction
No full textThe aseismicNazca Ridge produces localized flat-slab subduction beneath the South American
margin at latitudes 10 to 15 S. The geological evolution and the spatio-temporal pattern of deformation
of the upper plate have been strongly influenced by the presence of the flat slab. In this study, we
investigated the lithospheric thermal structure of this region by elaborating a 2D geothermal model
along a section across the top of the Nazca Ridge, the Peru–Chile trench, the Andean Cordillera, and the
Amazonian Basin, for a total length of 1000 km. For the sake of modelling, the crust of the overriding
plate was subdivided into two parts, i.e., a sedimentary cover (including the entire lithostratigraphic
sequence) and a crystalline basement. Applying an analytical methodology, we calculated geotherms
and isotherms by setting (i) thickness, (ii) density, (iii) heat production, and (iv) thermal conductivity
for each geological unit and considering (v) heat flux at theMoho, (vi) frictional heating produced by
faults, and (vii) plate convergence rate. The resulting model could make a significant advance in our
understanding of how flat slab geometry associated with the Nazca Ridge subduction affects the thermal
structure and hence the tectonic evolution of the region.Published7697OST1 Alla ricerca dei Motori GeodinamiciJCR Journa