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Editorial: Crust–mantle interactions of the India–Eurasia–Pacific convergence system
No full textOrogenic belts, encompassing both accretionary and collisional types, serve as a geological
archive of protracted convergence events between ocean–continent and continent–continent
tectonic plates. The extensive tectonic history of orogenic belts, such as the western Pacific and
Himalayan orogens, has served as a source of inspiration for numerous novel tectonic concepts
and geodynamic models that are currently at the forefront of contemporary solid-earth science.
Despite the incorporation of recent advancements such as observations andmodels, there are still
unresolved inquiries pertaining to the variety of subduction and collisional regions and the
underlying processes involved in subduction and collision. The investigations pertaining to
intricate lithospheric structures, interactions between the crust and mantle, and processes of
melting have received limited recognition. The objective of this Research Topic issue is to
consolidate contemporary studies on the interactions between the Earth’s crust andmantle in the
India–Eurasia convergence system and the Pacific–Eurasia convergence system. This task has
been achieved through the analysis and characterization of the lithospheric architecture of these
regions, with the aim of gaining a deeper understanding of the underlying geodynamic processes
in Southeastern Asia. The present Research Topic volume fallswithinthe realm of geophysics and
geodynamics, encompassing various specific themes that include:
• Crust–mantle interactions of the India–Eurasia and Pacific–Eurasia convergence
systems
• Identification of the lithospheric architecture of the
India–Eurasia and Pacific–Eurasia convergence systems
• Tectonic interactions of the India–Eurasia and Pacific–Eurasia
convergence systems
• Numerical modeling on tectonic interactions
In particular, in the present Research Topic, we present the
current state-of-the-art research on crust–mantle interactions of the
India–Eurasia–Pacific convergence system. Remarkable results have
been achieved by Yang et al., Wang et al., Zhang et al., Xiao et al.,
Deng et al., Liang et al., and Cheng et al.Published1276996JCR Journa
A New Approach for Real‐Time Erupted Volume Estimation From High‐Precision Strain Detection Validated by Satellite Topographic Monitoring
No full textTimely estimations of magma volumes emitted during an eruption or a sequence of explosive events are vital for investigating the eruptive activity and evaluating the associated hazard. A reliable method for estimating erupted volumes is based on the analysis of digital surface models that nowadays can be obtained subsequently using stereo or tri-stereo optical satellite imagery. However, the real-time estimation of the erupted volumes is still an open challenge. Here, we explore the capacity of extracting volume estimates from continuous measurements of volumetric strain changes recorded by borehole dilatometers. We compare the volumes derived from numerous high spatial resolution satellite images with high precision strain records at Etna during 2020–2022, when more than 60 lava fountains occurred. The good correlation between the two data sets shows that strain changes can be used as a proxy to estimate the emitted volumes both over time and in real-time.Publishede2023GL105424OSV2: Complessità dei processi vulcanici: approcci multidisciplinari e multiparametriciJCR Journa
Monitoring sources of volcanic activity at Mount Etna using pattern recognition techniques on infrasound signals
No full textInfrasound monitoring plays an important role in the framework of the surveillance of Mt. Etna, Europe’s largest active volcano. Compared to seismic monitoring, which is particularly effective for buried sources, infrasound signals mirror the activity of shallow sources like Strombolian explosions or degassing. The interpretation of infrasound signals is difficult to the untrained eye, as we have to account for volcanic and non-volcanic sources. The problem of handling large and complex data sets can be tackled with machine learning, namely pattern recognition techniques. Here, we focus on so-called ‘Unsupervised Learning’, where we identify groups of patterns being similar to each other. The degree of similarity is based on a metric measuring the distance among the features of the patterns. This work aims at the identification of typical regimes of infrasound radiation and their relation to the state of volcanic activity at Mt. Etna. For this goal, we defined features describing any infrasound pattern. These features were obtained using wavelet transform. We applied ‘Self-Organizing Maps’ (SOM) to the features projecting them to a 2-D representation space—the ‘map’. An intriguing aspect of SOM resides in the fact that the position of the patterns on the map can be expressed by a colour code, in a manner that similar patterns are assigned a similar colour code. This simplified representation of multivariate patterns allows to follow the development of their characteristics with time efficiently. During a training phase we considered a reference data set, which encompassed a large variety of scenarios. We identified typical groups of patterns which correspond to a specific regime of activity, being representative of the state of the volcano or noise conditions. These groups form areas on the 2-D maps. In a second step, we considered a test data set, which was not used during the training phase. Applying the same pre-processing as for the training data, we blindly assigned the test patterns to the regimes found before, identifying the one whose colour code is most similar to the one calculated to the test pattern. We are thus able to assess the validity of the prediction. The classification scheme presented provides a reliable assessment of the state of activity and adds useful and supplementary details to the results of the real-time automatic system in operation at Istituto Nazionale di Geofisica e Vulcanologia—Osservarorio Etneo. This is of particular importance when no visible information of the volcanic activity is available either for unfavourable meteorological conditions or during night time.IMPACT PROJECT (INGV Department strategic Projects - 2019)Published1-16JCR Journa
The first absolute gravity and height reference network in Sicily
No full textIn this poster we present the realization and the surveys performed to establish a new reference gravity and elevation network in Sicily with the aim to provide new reference systems useful for all the scientific and technological activities related to the gravity field and to the proper definition of a modern height system in this region. This network belongs to the under construction new Italian Reference Gravity Network (G0) that is part of the INGV Project Pianeta Dinamico, Task S2, during the period 2019-2022.
The Sicilian network encloses 5 stations (Catania, Centuripe, Milazzo, Noto, and Palermo), evenly distributed forming a large mesh network which roughly covers the entire Sicily (Fig.1). All absolute stations are hosted inside structures that guarantee protection for the instrumentation during the measurements and the necessary power supply. In addition to the absolute gravity value, at each station, the vertical gravity gradient and the gravity difference (Δg) between the indoor absolute gravity and an outdoor satellite station were also measured. Gravity measurements were carried out between the end of 2021 and the 2022 with the Microg LaCoste FG5#238 and the Scintrex CG-6 gravimeters for absolute and relative measurements, respectively. Gravity data have been corrected for known effects ensuring the reliability and accuracy at the µGal level. The coordinates and the orthometric heights were at the same time measured with mixed terrestrial and satellite local networks at each site. The precise coordinates obtained after the adjustments were useful to post-process the absolute gravity data and to refer all the gravity measurements presented in this work to the equipotential surface of the gravity field. Since three of the five selected stations were measured in the past, it was also possible to evaluate the long-term stability of the gravity values at these stations.SubmittedBologna, Italy7A. Geofisica per il monitoraggio ambiental
Earthquake size distributions are slightly different in compression vs extension
No full textThe earthquake size distribution is described by an exponential function governed by the b-value parameter. It has already been proven that the b-value depends on the differential stress and tectonic settings. Here, we propose a new method to group earthquakes using the kinematics of the interseismic geodetic strain rates and horizontal stress directions. We select the Italian peninsula as a case study, and we find that the b-value is significantly larger in the extensional setting than in the compressional one, although these differences are much smaller than previously reported. We also show that spatial fragmentation of uniform tectonic regimes leads to inaccurate b-value estimation due to the undersampling of earthquake size distribution. Given these results, we conclude that stress directions and geodetic data complement other geological or geophysical information and reduce the arbitrariness in drawing zones for a seismotectonic model.Published398OST2 Deformazione e Hazard sismico e da maremotoJCR Journa
Gas buffering of magma chamber contraction during persistent explosive activity at Mt. Etna volcano
No full textA sequence of more than 20 short-lasting explosive eruptions took place at Mt. Etna volcano, during a 2-month period in 2021. Here we perform a joint analysis of the gravity decrease and ground deflation that accompanied the sequence of eruptions. Results from this joint analysis are cross-checked against the output of a numerical code providing independent geochemical insight on how the density of the magmatic liquid/gas mixture in the source reservoir varies as a function of the pressure. This cross-analysis provides a framework to explain why (i) the bulk volume reduction sensed by the ground deformation data is much lower than the volume of the erupted products and (ii) the observed gravity changes point to a strong mass decrease, incompatible with a pure mechanism of magma withdrawal. We conclude that pressure-driven gas exsolution and expansion compensated the withdrawal of magma, thus buffering the contraction of the source reservoir and leading to the inferred mass decrease.Published471OSV2: Complessità dei processi vulcanici: approcci multidisciplinari e multiparametriciJCR Journa
An experimental approach to unravel 2D ground resonances: application to an alluvial-sedimentary basin
No full textThe study of ground resonances is important to assess seismic site amplification and to infer information on the geometrical and mechanical properties of the resonating structures. 1D- and 2D-type resonances imply different dynamic behavior that can be distinguished by inspecting the individual spectral components of single-station microtremor measurements. Typically, 2D resonance modes develop along cross-sections of deep sediment-filled val- leys and consist of longitudinal, transverse and vertical modes that can be identified as spectral peaks when ground motion is recorded parallel to the axes of the valley. In the case of more complex geometries, such as sedimentary basins, resonance modes are more difficult to predict and depend on the unknown complexity of the buried bedrock geometry. We show how a simple signal rotation procedure applied to single-station microtremor recordings reveals the underlying 2D resonance pattern. The method allows assessing the axes of motion of buried geological structures and identifying 2D resonance modes along these axes. Their directionality, frequency and amplitude features are then analyzed to extract information on the bedrock geometry. We test our method in the Bolzano alluvial-sedimentary basin and we observe that apparently complicated resonance patterns may be simplified by locally referring to the simplest description of the phenomenon as 2D resonance of a valley slice. The bedrock morphology can be decom- posed into 2D-like geometries, i.e., excavated channels, and the observed resonances develop within cross-sections of these channels.Published74OST2 Deformazione e Hazard sismico e da maremotoJCR Journa
The consolidated European synthesis of CH4 and N2O emissions for the European Union and United Kingdom: 1990–2019
No full textKnowledge of the spatial distribution of the fluxes of greenhouse gases (GHGs) and their temporal variability as well as flux attribution to natural and anthropogenic processes is essential to monitoring the progress in mitigating anthropogenic emissions under the Paris Agreement and to inform its global stocktake. This study provides a consolidated synthesis of CH4 and N2O emissions using bottom-up (BU) and top-down (TD) approaches for the European Union and UK (EU27 + UK) and updates earlier syntheses (Petrescu et al., 2020, 2021). The work integrates updated emission inventory data, process-based model results, data-driven sector model results and inverse modeling estimates, and it extends the previous period of 1990–2017 to 2019. BU and TD products are compared with European national greenhouse gas inventories (NGHGIs) reported by parties under the United Nations Framework Convention on Climate Change (UNFCCC) in 2021. Uncertainties in NGHGIs, as reported to the UNFCCC by the EU and its member states, are also included in the synthesis. Variations in estimates produced with other methods, such as atmospheric inversion models (TD) or spatially disaggregated inventory datasets (BU), arise from diverse sources including within-model uncertainty related to parameterization as well as structural differences between models. By comparing NGHGIs with other approaches, the activities included are a key source of bias between estimates, e.g., anthropogenic and natural fluxes, which in atmospheric inversions are sensitive to the prior geospatial distribution of emissions. For CH4 emissions, over the updated 2015–2019 period, which covers a sufficiently robust number of overlapping estimates, and most importantly the NGHGIs, the anthropogenic BU approaches are directly comparable, accounting for mean emissions of 20.5 Tg CH4 yr−1 (EDGARv6.0, last year 2018) and 18.4 Tg CH4 yr−1 (GAINS, last year 2015), close to the NGHGI estimates of 17.5±2.1 Tg CH4 yr−1. TD inversion estimates give higher emission estimates, as they also detect natural emissions. Over the same period, high-resolution regional TD inversions report a mean emission of 34 Tg CH4 yr−1. Coarser-resolution global-scale TD inversions result in emission estimates of 23 and 24 Tg CH4 yr−1 inferred from GOSAT and surface (SURF) network atmospheric measurements, respectively. The magnitude of natural peatland and mineral soil emissions from the JSBACH–HIMMELI model, natural rivers, lake and reservoir emissions, geological sources, and biomass burning together could account for the gap between NGHGI and inversions and account for 8 Tg CH4 yr−1. For N2O emissions, over the 2015–2019 period, both BU products (EDGARv6.0 and GAINS) report a mean value of anthropogenic emissions of 0.9 Tg N2O yr−1, close to the NGHGI data (0.8±55 % Tg N2O yr−1). Over the same period, the mean of TD global and regional inversions was 1.4 Tg N2O yr−1 (excluding TOMCAT, which reported no data). The TD and BU comparison method defined in this study can be operationalized for future annual updates for the calculation of CH4 and N2O budgets at the national and EU27 + UK scales. Future comparability will be enhanced with further steps involving analysis at finer temporal resolutions and estimation of emissions over intra-annual timescales, which is of great importance for CH4 and N2O, and may help identify sector contributions to divergence between prior and posterior estimates at the annual and/or inter-annual scale. Even if currently comparison between CH4 and N2O inversion estimates and NGHGIs is highly uncertain because of the large spread in the inversion results, TD inversions inferred from atmospheric observations represent the most independent data against which inventory totals can be compared. With anticipated improvements in atmospheric modeling and observations, as well as modeling of natural fluxes, TD inversions may arguably emerge as the most powerful tool for verifying emission inventories for CH4, N2O and other GHGs.Published1197–1268OSA2: Evoluzione climatica: effetti e loro mitigazioneJCR Journa
Machine learning models to complete rainfall time series databases affected by missing or anomalous data
No full textIn recent years, artificial intelligence in geosciences is spreading more and more, thanks to the availability of a large amount of data. In particular, the development of automatic raingauges networks allows to get rainfall data and makes these techniques effective, even if the performance of artificial intelligence models is a consequence of the coherency and quality of the input data. In this work, we intended to provide machine learning models capable of predicting rainfall data starting from the values of the nearest raingauges at one historic time point. Moreover, we investigated the influence of the anomalous input data on the prediction of rainfall data. We pursued these goals by applying machine learning models based on Linear Regression, LSTM and CNN architectures to several raingauges in Tuscany (central Italy). More than 75% of the cases show an R2 higher than 0.65 and a MAE lower than 4 mm. As expected, we emphasized a strong influence of the input data on the prediction capacity of the models. We quantified the model inaccuracy using the Pearson's correlation. Measurement anomalies in time series cause major errors in deep learning models. These anomalous data may be due to several factors such as temporary malfunctions of raingauges or weather conditions. We showed that, in both cases, the data-driven model features could highlight these situations, allowing a better management of the raingauges network and rainfall databases.Published3717-3728OSA2: Evoluzione climatica: effetti e loro mitigazioneJCR Journa
A multidisciplinary approach gives new insights into the shallow structural setting of the Val d'Agri oilfield (Basilicata, southern Apennines, Italy);
No full textThe Val d’Agri (VA) oilfield in the Lucanian Apennines (southern Italy), represents the largest onshore in Europe. Since the 1990's, hydrocarbons are produced from a fractured carbonate reservoir with an average extraction rate of 7*104 barrels/day of oil and 3*106 Smc/day of gas. Part of the wastewater has been re-injected since 2006 into a marginal portion of the reservoir by a high-rate well (Costa Molina 2, CM2). Charged by the Italian oil and gas safety authority, the National Institute of Geophysics and Volcanology (INGV) monitors the VA industrial hydrocarbon operations through the research activity of a dedicated working group (CMS, Centro di Monitoraggio del Sottosuolo) and according to the governmental monitoring guidelines. The CMS operates the real-time acquisition and offline analyses of seismic data recorded at 56 seismic stations associated with public and private local seismic networks. The principal aim of the CMS is to investigate the risk associated with industrial activities that can induce or trigger seismic events by producing stress changes within the upper crustal volume. Previous works have highlighted a spatio-temporal relationship between micro-seismicity (ML ≤ 2.2) and wastewater injection, delineating a NE-dipping back-thrust near the CM2. Part of the microseismicity recorded in the southwestern portion of the VA has also been associated with the water level changes of the Pertusillo lake. One of the main challenges is to define an accurate structural setting of the VA to understand the potential of earthquakes in the area and investigate the presence of active faults. The VA consists of a Quaternary extensional tectonic basin and it is one of the areas of highest seismic hazard in Italy (Basilicata, 1857, M7 earthquake). The basin is bounded by two parallel and oppositely dipping normal fault systems: the Monti della Maddalena Fault System (MMFS) on its western side and the Eastern Agri Fault System (EAFS) on the eastern one. The characterization of the ongoing tectonic activity of the MMFS and EAFS, and their hierarchical relationship is still generating debate among the scientific community. We adopt a multidisciplinary approach based on detailed geological-structural, geophysical and seismic analyses, and electrical resistivity tomography, aimed at reconstructing the subsurface geology of the area and recognizing and characterizing the active and capable faults, and the associated potential for local seismic hazard. We present and discuss the results of this work, focusing on the relative location of seismic events that occurred between March and June 2022. The outcomes allow inferring interesting geologic constraints, highlighting the relationships between the distribution of local seismicity and the structural setting of the area in the uppermost crust (depth < 6 km).PublishedVienna1T. Struttura della Terr