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  • 04.06. Seismology  (43)
  • 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques
  • 04.04. Geology
  • Data analysis / ~ processing
  • E62
  • MDPI  (35)
  • Oxford University Press  (16)
  • Wiley  (11)
  • 1
    Publication Date: 2024-01-08
    Description: In this paper, we provide a characterisation of the ionosphere from April 2018 to September 2022 for 48 investigated months. We used the data of the China Seismo Electromagnetic Satellite (CSES-01), which is a sun-synchronous satellite with five days of revisit time and fixed local time of about 2 a.m. and 2 p.m. The unique orbit of CSES-01 permitted us to produce a monthly background of the ionosphere for night- and daytime with median values acquired during geomagnetic quiet time in equatorial and mid-latitude regions (i.e., between 50° S and 50° N of geographical latitude). We compared the obtained CSES-01 monthly median values with the solar activity in terms of sunspot numbers, and we found a high correlation of 0.89 for nighttime and 0.85 for daytime between the mean sunspot number and the maximum of the characterised CSES-01 Ne map values. In addition, we extracted all the anomalous positive increases in CSES-01 electron density and compared them with the Worldwide M5.5+ shallow earthquakes. We tested two different definitions of anomaly based on median and interquartile range or (mild) outliers. We tried two relationships between anomalies inside Dobrovolsky’s area before the earthquake and the magnitude of the same seismic events: one which considers distance in space and time and a second which only uses the anticipation time of the anomaly before the earthquake. Using both anomaly definitions, we searched the best coefficients for these two laws for mid-latitude and equational regions. We found that the best coefficients are independent of the anomaly definition, but better accuracy (greater than 80%) is obtained for the outlier definition. Finally, using receiving operating characteristic (ROC) curves, we show that CSES-01 increases seem statistically correlated to the incoming seismic activity.
    Description: Published
    Description: 1527
    Description: OST4 Descrizione in tempo reale del terremoto, del maremoto, loro predicibilità e impatto
    Description: OSA3: Climatologia e meteorologia spaziale
    Description: JCR Journal
    Keywords: CSES ; electron density ; earthquake ; ionosphere ; satellite background ; 01.02. Ionosphere ; 04.06. Seismology ; 05.07. Space and Planetary sciences
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 2
    Publication Date: 2024-04-03
    Description: This article has been accepted for publication in Geophysical Journal International ©:The Author(s) 2023. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.Uploaded in accordance with the publisher's self-archiving policy. All rights reserved.
    Description: Estimation of local seismic response plays a key role in assessing local seismic hazard and particularly in the design of shaking scenarios. Modelling local seismic response involves knowing of the shear wave velocity (Vs) and quality factor (Qs) profiles for the site in question. The many techniques that have been developed to assess Vs in surface deposits produce reliable measurements of Vs , but these rarely correspond to direct measurements of Qs . The latter is often considered through damping measures from laboratory tests on small-scale soil samples, which can provide information primarily on intrinsic attenuation, neglecting the contribution of scattering effects. In this paper, using seismic recordings obtained at the surface and in boreholes at 100 m depth, we estimate an average value of Qs of some characteristic alluvial deposits of the Po Plain (northern Italy). Data come from a microseismic network which sampled an almost uniform lithology in the central Po Plain and consisted of three surface and four borehole stations with an interstation distance of about 2 km. The average value of Qs of the shallowest 100 m of the sedimentary strata, Qs100, is estimated by considering: (1) the high-frequency attenuation of seismic waves due to propagation through the corresponding stratigraphy and (2) the interference between incident and surface-reflected waves observed at borehole stations. We parametrize the first through k0_100, the difference between the values of the spectral decay parameter kappa (k) estimated at the surface and at the boreholes depth, respectively. We use the second in order to compute Vs100, the time-averaged Vs referred to the uppermost 100 m stratigraphy. We obtain: k0_100 = (11 ± 3) ms, Vs100 = (309 ± 11) m s −1 and Qs100 = 31 ± 10. At the surface, the estimated values of the site-specific kappa, k0, are found to range from 75 to 79 ms. As expected, these results are in good agreement with studies performed in other sites characterized by sandy or clayey lithologies, and can be usefully used in site response analysis at sites where the rigidity is mainly controlled by lithostatic pressure.
    Description: Comune di Minerbio (grant: “Sperimentazione ILG Minerbio”; grant number: 0913.010).
    Description: Published
    Description: 2075–2094
    Description: OST2 Deformazione e Hazard sismico e da maremoto
    Description: JCR Journal
    Keywords: Earthquake ground motions ; Seismic attenuation ; Site effects ; Wave propagation ; Wave scattering and diffraction ; 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 3
    Publication Date: 2024-02-07
    Description: An effective earthquake early warning system requires rapid and reliable earthquake source detection. Despite the numerous proposed epicenter localization solutions in recent years, their utilization within the Internet of Things (IoT) framework and integration with IoT-oriented cloud platforms remain underexplored. This paper proposes a complete IoT architecture for earthquake detection, localization, and event notification. The architecture, which has been designed, deployed, and tested on a standard cloud platform, introduces an innovative approach by implementing P-wave "picking" directly on IoT devices, deviating from traditional regional earthquake early warning (EEW) approaches. Pick association, source localization, event declaration, and user notification functionalities are also deployed on the cloud. The cloud integration simplifies the integration of other services in the architecture, such as data storage and device management. Moreover, a localization algorithm based on the hyperbola method is proposed, but here, the time difference of arrival multilateration is applied that is often used in wireless sensor network applications. The results show that the proposed end-to-end architecture is able to provide a quick estimate of the earthquake epicenter location with acceptable errors for an EEW system scenario. Rigorous testing against the standard of reference in Italy for regional EEW showed an overall 3.39 s gain in the system localization speed, thus offering a tangible metric of the efficiency and potential proposed system as an EEW solution.
    Description: Published
    Description: 8431
    Description: OST4 Descrizione in tempo reale del terremoto, del maremoto, loro predicibilità e impatto
    Description: JCR Journal
    Keywords: Internet of Things ; cloud computing ; early warning systems ; earthquake localization ; 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 4
    Publication Date: 2024-02-07
    Description: A catalogue of precisely located micro-seismicity is fundamental for investigating seismicity and rock physical properties in active tectonic and volcanic regions and for the definition of a ‘baseline’ seismicity, required for a safe future exploitation of georesource areas. In this study, we produce the first manually revised catalogue of micro-seismicity for Co. Donegal region (Ireland), an area of about 50K M2 of on-going deformation, aimed at localizing natural micro-seismic events occurred between 2012 and 2015. We develop a stochastic method based on a Markov chain Monte Carlo (McMC) sampling approach to compute earthquake hypocentral location parameters. Our results indicates that micro-seismicity is present with magnitudes lower than 2 (the highest magnitude is 2.8).The recorded seismicity is almost clustered along previously mapped NE-SW trending, steeply dipping faults and confined within the upper crust (focal depth less than 10 km). We also recorded anthropogenic seismicity mostly related to quarries' activity in the study area.
    Description: Published
    Description: 62-76
    Description: OST1 Alla ricerca dei Motori Geodinamici
    Description: JCR Journal
    Keywords: 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 5
    Publication Date: 2024-03-12
    Description: This article has been accepted for publication in Geophysical Journal International ©:The Author(s) 2023. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.Uploaded in accordance with the publisher's self-archiving policy. All rights reserved.
    Description: We present the results from a fully unconstrained moment tensor inversion of induced seismic events in a complex and high seismic hazard region (Val d’Agri basin, Southern Italy). The study area hosts two well-documented cases of induced microseismicity linked to (i) a wastewater injection well of a giant oilfield (the largest in onshore Europe), and (ii) severe seasonal level changes of an artificial lake. In order to gather information on the non-doublecouple components of the source and to better understand the rupture mechanisms, we analyse seismic events recorded during daily injection tests in the disposal well. The computed moment tensors have significant non-double-couple components that correlate with the well-head injection pressure. The injection parameters strongly influence the rupture mechanism that can be interpreted as due to the opening/closing of a fracture network inside a fault zone of a pre-existing thrust fault. For the case of the reservoir-induced seismicity, no direct correlations are observed with the loading/unloading of the reservoir.
    Description: Published
    Description: 1617–1627
    Description: OST3 Vicino alla faglia
    Description: JCR Journal
    Keywords: 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 6
    Publication Date: 2024-05-16
    Description: Artworks play a fundamental role in the cultural and economic assets of communities, enhancing their identity and helping with social integration. Despite their importance, they are not always adequately protected against degradation, which can be induced by aging, atmospheric and human-induced occurrences, and catastrophic events. Earthquakes certainly represent one of the main risks for art objects; however, traffic, construction works, and shipment can also represent a threat to art goods. Therefore, the assessment of the vulnerability of art collections to dynamic excitations plays a crucial role in their conservation, and it has been collecting increasing attention from researchers, academics, and museum managers. This work focuses on the vulnerability of the art collections exhibited at the “Gaio Cilnio Mecenate” museum in Arezzo. Namely, it aims to assess the effective dynamic loading experienced by the artworks, which is a function of the dynamic propagation played by the foundation soil, the building, and the displayers used for the exhibition. In this study, the dynamic properties of some of the displayers used for exhibiting the art collections are investigated by performing an experimental survey. The analysis of the experimental data led to the assessment of the proper frequencies of the displayers, which were compared to those of the building and the foundation soil of the museum.
    Description: Published
    Description: 2701
    Description: JCR Journal
    Keywords: art collections ; seismic vulnerability ; seismic safety assessment ; experimental dynamic monitoring ; 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 7
    Publication Date: 2024-05-09
    Description: To understand the seismic hazard of a subduction zone, it is necessary to know the geometry, location and mechanical characteristics of the interplate boundary below which an oceanic plate is thrust downward. By considering the azimuthal dependence of converted P-to-S (Ps) amplitudes in receiver functions, we have detected the interplate boundary in the Makran subduction zone, revealing significant seismic anisotropy at the base of the accretionary wedge above the slab before it bends down beneath the Jaz Murian basin. This anisotropic feature aligns with a zone of reduced seismic velocity and a high primary/secondary wave velocity ratio (Vp/Vs), as documented in previous studies. The presence of this low-velocity highly anisotropic layer at the base of the accretionary wedge, likely representing a low-strength shear zone, could possibly explain the unusually wide accretionary wedge in Makran. Additionally, it may impact the location and width of the locked zone along the interplate boundary.
    Description: Iranian National Science Foundation (INSF)
    Description: Published
    Description: 64-74
    Description: OST1 Alla ricerca dei Motori Geodinamici
    Description: JCR Journal
    Keywords: Earthquake hazards, Seismic anisotropy, Crustal structure, Subduction zone processes ; 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 8
    Publication Date: 2024-05-09
    Description: Gravaglione represents one of the main swallow holes of the Canale di Pirro, low Murge, Apulia region, Italy. Here, after an intense rainstorm, a huge volume of rainwater accumulates at the surface. The drainage dynamics suggest that the Gravaglione could be part of a large, and potentially unknown, karst system. To verify this hypothesis and to acquire useful information on the possible karst environment features, an integrated aerial and geophysical multiscale and multimethod approach was applied. In particular, aerial photogrammetry, ground penetrating radar measurements and electrical resistivity tomography surveys were hence conducted and integrated to potentially detect the caves, define the subsurface volume possibly affected by karst systems and to verify the existence of links between the surficial morphology and the subsoil structure. The results provided interesting insights regarding the presence of a complex karst system extending up to 200 m b.g.l. and with a marked 3D nature. Overall, the Gravaglione case study demonstrates the geophysical approach validity and poses the basis for the development of an expeditive and low-cost high-resolution strategy for detecting and characterizing karst caves.
    Description: Published
    Description: 3820
    Description: OSA1: Variazioni del campo magnetico terrestre, imaging crostale e sicurezza del territorio
    Description: JCR Journal
    Keywords: karst environment ; cave detection ; ground penetrating radar ; electrical resistivity tomography ; 04.04. Geology ; 04.02. Exploration geophysics
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 9
    Publication Date: 2024-06-26
    Description: Variations in the CO2 dissolved in water springs have long been observed near the epicenters of moderate and strong earthquakes. In a recent work focused on data collected during the 2017–2021 period from a monitoring site in the Northern Apennines, Italy, we noticed a significant correlation between CO2 anomalies and moderate-to-weak seismic activity. Here, we extended this analysis by focusing on data collected from the same site during a different period (2010–2013) and by integrating the CENSUS method with an artificial neural network (ANN) in the already-tested protocol. As in our previous work, a fit of the computed residual CO2 distributions allowed us to evidence statistically relevant CO2 anomalies. Thus, we extended a test of the linear dependence of these anomalies to seismic events over a longer period by means of binary correlations. This new analysis also included strong seismic events. Depending on the method applied, we observed different time lags. Specifically, using the CENSUS methodology, we detected a CO2 anomaly one day ahead of the earthquake and another anomaly eleven days ahead. However, no anomaly was observed with the ANN methodology. We also investigated possible correlations between CO2 concentrations and rain events and between rain events and earthquakes, highlighting the occurrence of a CO2 anomaly one day after a rain event of at least 10 mm and no linear dependence of seismic and rain events. Similar to our previous work, we achieved a probability gain of around 4, which is the probably of earthquake increases after CO2 anomaly observations.
    Description: Published
    Description: 739
    Description: OST3 Vicino alla faglia
    Description: JCR Journal
    Keywords: CO2 anomalies ; continuous monitoring ; small earthquakes ; statistical correlations ; 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 10
    Publication Date: 2023-02-27
    Description: One of the main constraints in assessing shallow landslide hazards through physically based models is the need to characterize the geotechnical parameters of the involved materials. Indeed, the quantity and quality of input data are closely related to the reliability of the results of every model used, therefore data acquisition is a critical and time-consuming step in every research activity. In this perspective, we reviewed all official certificates of tests performed through 30 years at the Geotechnics Laboratory of the Earth Science Department (University of Firenze, Firenze, Italy), compiling a dataset in which 380 points are accurately geolocated and provide information about one or more geotechnical parameters used in slope stability modeling. All tests performed in the past (in the framework of previous research programs, agreements of cooperation, or to support didactic activities) were gathered, homogenized, digitalized, and geotagged. The dataset is based on both on-site tests and laboratory tests, it accounts for 40 attributes, among which 13 are descriptive (e.g., lithology or location) and 27 may be of direct interest in slope stability modeling as input parameters. The dataset is made openly available and can be useful for scientists or practitioners committed to landslide modeling.
    Description: Published
    Description: 37
    Description: 4IT. Banche dati
    Description: JCR Journal
    Keywords: Geotechnics ; Hydrology ; Slope stability ; Landslide ; Modeling ; Geotechnical database ; Input data ; Cohesion ; Internal friction angle ; Permeability ; 04.04. Geology ; 03.02. Hydrology ; 05.02. Data dissemination
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 11
    Publication Date: 2023-03-20
    Description: We studied the long-term features of earthquakes caused by a fault system in the northern Adriatic sea that experienced a series of quakes beginning with two main shocks of magnitude 5.5 and 5.2 on 9 November 2022 at 06:07 and 06:08 UTC, respectively. This offshore fault system, identified through seismic reflection profiles, has a low slip rate of 0.2–0.5 mm/yr. As the historical record spanning a millennium does not extend beyond the inter-event time for the largest expected earthquakes (M ' 6.5), we used an earthquake simulator to generate a 100,000-year catalogue with 121 events of Mw 5.5. The simulation results showed a recurrence time (Tr) increasing from 800 yrs to 1700 yrs as the magnitude threshold increased from 5.5 to 6.5. However, the standard deviation s of inter-event times remained at a stable value of 700 yrs regardless of the magnitude threshold. This means that the coefficient of variation (Cv = s/Tr) decreased from 0.9 to 0.4 as the threshold magnitude increased from 5.5 to 6.5, making earthquakes more predictable over time for larger magnitudes. Our study supports the use of a renewal model for seismic hazard assessment in regions of moderate seismicity, especially when historical catalogues are not available.
    Description: Published
    Description: 3746
    Description: 2T. Deformazione crostale attiva
    Description: 4T. Sismicità dell'Italia
    Description: 6T. Studi di pericolosità sismica e da maremoto
    Description: JCR Journal
    Keywords: Numerical modelling ; earthquake simulator ; statistical methods ; earthquake clustering ; northern Adriatic Sea ; 04.07. Tectonophysics ; 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 12
    Publication Date: 2023-01-16
    Description: We present the results of a consistency check performed over a flatfile of accelerometric data extracted from the ITalian ACcelerometric Archive (ITACA), enriched with velocimetric records of events with magnitude M 〈 4.0. The flatfile, called ITACAext, includes 31,967 waveforms from 1709 shallow crustal earthquakes, in the magnitude range from 3.0 to 6.9, and occurred in the period of 1972–2019 in Italy. The consistency check is carried out by decomposing the residuals obtained from a reference ground motion model, for the ordinates of the 5% damped acceleration response spectra. The residual components are subsequently analyzed to identify a list of events, stations, and records that significantly deviate from the median trends predicted by the model. The results indicate that about 10% of events and stations are outliers, while only 1% of the waveforms present anomalous amplitudes. The asymmetrical azimuthal coverage of seismic stations around the epicenter is the most common issue that can affect the estimates of the repeatable event residual term. On the other hand, peculiarities in the site-response or wrong estimates of the soil parameters (i.e., the average shear-wave velocity in the first 30 m of the subsoil) are the main issues related to the repeatable station residuals. Finally, single records can show large residuals because of issues related to signal acquisition (e.g., multiple events, noisy records) or possible near-source effects (e.g., rupture directivity).
    Description: Published
    Description: 334
    Description: 5T. Sismologia, geofisica e geologia per l'ingegneria sismica
    Description: JCR Journal
    Keywords: ground-motion models ; residual analysis ; consistency check ; strong motion flatfile ; 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 13
    Publication Date: 2023-01-27
    Description: Non-stationary signals are often analyzed using raw waveform data or spectrograms of those data; however, the possibility of alternative time–frequency representations being more informative than the original data or spectrograms is yet to be investigated. This paper tested whether alternative time–frequency representations could be more informative for machine learning classification of seismological data. The mentioned hypothesis was evaluated by training three well-established convolutional neural networks using nine time–frequency representations. The results were compared to the base model, which was trained on the raw waveform data. The signals that were used in the experiment are three-component seismogram instances from the Local Earthquakes and Noise DataBase (LEN-DB). The results demonstrate that Pseudo Wigner–Ville and Wigner–Ville time–frequency representations yield significantly better results than the base model, while spectrogram and Margenau–Hill perform significantly worse (p 〈 0.01). Interestingly, the spectrogram, which is often used in signal analysis, had inferior performance when compared to the base model. The findings presented in this research could have notable impacts in the fields of geophysics and seismology as the phenomena that were previously hidden in the seismic noise are now more easily identified. Furthermore, the results indicate that applying Pseudo Wigner–Ville or Wigner–Ville time–frequency representations could result in a large increase in earthquakes in the catalogs and lessen the need to add new stations with an overall reduction in the costs. Finally, the proposed approach of extracting valuable information through time–frequency representations could be applied in other domains as well, such as electroencephalogram and electrocardiogram signal analysis, speech recognition, gravitational waves investigation, and so on.
    Description: COST project G2Net CA17137 A network for Gravitational Waves, Geophysics and Machine Learning.
    Description: Published
    Description: 965
    Description: 8T. Sismologia in tempo reale e Early Warning Sismico e da Tsunami
    Description: JCR Journal
    Keywords: earthquake detection; convolutional neural network; non-stationary signal analysis; classification; time–frequency representation ; 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 14
    Publication Date: 2023-02-02
    Description: Mt. Vesuvius is a high-hazard active volcano surrounded by a densely populated area. Since human activities generate high levels of seismic noise, recognizing low-amplitude seismic events in the signals recorded by the local seismic monitoring network operating at Vesuvius is very difficult. Here, we describe an automatic procedure applied to continuous data with the aim of finding low-amplitude–low-frequency events hidden in the recorded signals. The methodology is based on the computation of two spectral parameters, central frequency Ω and shape factor ẟ, at selected sites, and the coherence of the seismic signal among different sites. The proposed procedure is applied to 28 months of recordings from 2019 to 2021, tuning the search parameters in order to find low-frequency signals similar to those occasionally observed in the past at the same volcano. The results allowed us to identify 80 seismic events that have the spectral features of low-frequency earthquakes or tremor. Among these, 12 events characterized by sufficiently high signal-to-noise ratio have been classified as deep low-frequency earthquakes, most of which are not reported in the catalog. The remaining events (more than 60) are characterized by similar spectral features but with an extremely low amplitude that prevents any reliable location of the source and definitive classification. The results of this work demonstrate that the low-frequency endogenous activity at Mt. Vesuvius volcano is more frequent that previously thought.
    Description: The dataset used in this paper was collected by mobile and permanent seismic networks, as carried out within the framework of the Agreement (Annex A) between the Italian Civil Protection Department (DPC) and INGV.
    Description: Published
    Description: 194
    Description: 2V. Struttura e sistema di alimentazione dei vulcani
    Description: JCR Journal
    Keywords: 04.06. Seismology
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  • 15
    Publication Date: 2023-04-06
    Description: Since 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.
    Description: Published
    Description: 105
    Description: 2T. Deformazione crostale attiva
    Description: JCR Journal
    Keywords: Ground deformation ; Remote Sensing ; PS-InSAR ; Subsidence ; Hidden Faults ; 04.04. Geology
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  • 16
    Publication Date: 2023-06-12
    Description: In this work, we propose a geodetic model for the seismic sequence, with doublet earthquakes, that occurred in Bandar Abbas, Iran, in November 2021. A dataset of Sentinel-1 images, processed using the InSAR (Interferometric Synthetic Aperture Radar) technique, was employed to identify the surface deformation caused by the major events of the sequence and to constrain their geometry and kinematics using seismological constraints. A Coulomb stress transfer analysis was also applied to investigate the sequence’s structural evolution in space and time. A linear inversion of the InSAR data provided a non-uniform distribution of slip over the fault planes. We also performed an accurate relocation of foreshocks and aftershocks recorded by locally established seismographs, thereby allowing us to determine the compressional tectonic stress regime affecting the crustal volume. Despite the very short time span of the sequence, our results clearly suggest that distinct blind structures that were previously unknown or only suspected were the causative faults. The first Mw 6.0 earthquake occurred on an NNE-dipping, intermediate-angle, reverse-oblique plane, while the Mw 6.4 earthquake occurred on almost horizontal or very low-angle (SSE-dipping) reverse segments with top-to-the-south kinematics. The former, which cut through and displaced the Pan-African pre-Palaeozoic basement, indicates a thick-skinned tectonic style, while the latter rupture(s), which occurred within the Palaeozoic–Cenozoic sedimentary succession and likely exploited the stratigraphic mechanical discontinuities, clearly depicts a thin-skinned style.
    Description: Published
    Description: 2981
    Description: 2T. Deformazione crostale attiva
    Description: JCR Journal
    Keywords: 04.06. Seismology
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  • 17
    Publication Date: 2022-03-07
    Description: The Pollino range is a region of slow deformation where earthquakes generally nucleate on low-angle normal faults. Recent studies have mapped fault structures and identified fluid related dynamics responsible for historical and recent seismicity in the area. Here, we apply the coda-normalization method at multiple frequencies and scales to image the 3-D P-wave attenuation (QP) properties of its slowly deforming fault network. The wide-scale average attenuation properties of the Pollino range are typical for a stable continental block, with a dependence of QP on frequency of Q−1 P = (0.0011   0.0008) f (0.36 0.32). Using only waveforms comprised in the area of seismic swarms, the dependence of attenuation on frequency increases [Q−1 P = (0.0373   0.0011) f (−0.59 0.01)], as expected when targeting seismically active faults. A shallow very-low-attenuation anomaly (max depth of 4–5 km) caps the seismicity recorded within the western cluster 1 of the Pollino seismic sequence (2012, maximum magnitude Mw = 5.1). High-attenuation volumes below this anomaly are likely related to fluid storage and comprise the western and northern portions of cluster 1 and the Mercure basin. These anomalies are constrained to the NW by a sharp low-attenuation interface, corresponding to the transition towards the eastern unit of the Apennine Platform under the Lauria mountains. The low-seismicity volume between cluster 1 and cluster 2 (maximum magnitude Mw = 4.3, east of the primary) shows diffuse low-to-average attenuation features. There is no clear indication of fluid-filled pathways between the two clusters resolvable at our resolution. In this volume, the attenuation values are anyway lower than in recognized low-attenuation blocks, like the Lauria Mountain and Pollino Range. As the volume develops in a region marked at surface by small-scale cross-faulting, it suggests no actual barrier between clusters, more likely a system of small locked fault patches that can break in the future. Our model loses resolution at depth, but it can still resolve a 5-to-15-km-deep high-attenuation anomaly that underlies the Castrovillari basin. This anomaly is an ideal deep source for the SE-to-NW migration of historical seismicity. Our novel deep structural maps support the hypothesis that the Pollino sequence has been caused by a mechanism of deep and lateral fluid-induced migration.
    Description: Natural Environment Research Council (NERC) Centre for Doctoral Training (CDT) in Oil and Gas. University of Aberdeen.
    Description: Published
    Description: 536–547
    Description: 4T. Sismicità dell'Italia
    Description: JCR Journal
    Keywords: body waves ; seismic attenuation ; seismic tomography ; 04.06. Seismology
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  • 18
    Publication Date: 2022-02-18
    Description: We applied a new version of physics-based earthquake simulator upon a seismogenic model of the Italian seismicity derived from the latest version of the Database of Individual Seismogenic Sources (DISS). We elaborated appropriately for their use within the simulator all fault systems identified in the study area. We obtained synthetic catalogs spanning hundreds of thousands of years. The resulting synthetic seismic catalogs exhibit typical magnitude, space and time features that are comparable to those obtained by real observations. A typical aspect of the observed seismicity is the occurrence of earthquake sequences characterized by multiple main shocks of similar magnitude. Special attention was devoted to verifying whether the simulated catalogs include this notable aspect, by the use of an especially developed computer code. We found that the phenomenon of Coulomb stress transfer from causative to receiving source patches during an earthquake rupture has a critical role in the behavior of seismicity patterns in the simulated catalogs. We applied the simulator to the seismicity of the northern and central Apennines and compared the resulting synthetic catalog with the observed seismicity for the period 1650–2020. The result of this comparison supports the hypothesis that the occurrence of sequences containing multiple mainshocks is not just a casual circumstance.
    Description: Published
    Description: 2062
    Description: 2T. Deformazione crostale attiva
    Description: 3T. Fisica dei terremoti e Sorgente Sismica
    Description: 4T. Sismicità dell'Italia
    Description: JCR Journal
    Keywords: numerical modeling ; earthquake simulator ; statistical methods ; earthquake clustering ; 04.06. Seismology ; 04.07. Tectonophysics
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 19
    Publication Date: 2022-02-24
    Description: The identification of the mechanisms responsible for the deformation of calderas is of primary importance for our understanding of the dynamics of magmatic systems and the evaluation of volcanic hazards. We analyze twenty years (1997–2018) of geodetic measurements on Ischia Island (Italy), which include the Mt. Epomeo resurgent block, and is affected by hydrothermal manifestations and shallow seismicity. The data from the GPS Network and the leveling route show a constant subsidence with values up to 􀀀15 2.0 mm/yr and a centripetal displacement rate with the largest deformations on the southern flank of Mt. Epomeo. The joint inversion of GPS and levelling data is consistent with a 4 km deep source deflating by degassing and magma cooling below the southern flank of Mt. Epomeo. The depth of the source is supported by independent geophysical data. The Ischia deformation field is not related to the instability of the resurgent block or extensive gravity or tectonic processes. The seismicity reflects the dynamics of the shallow hydrothermal system being neither temporally nor spatially related to the deflation.
    Description: Published
    Description: 4648
    Description: 1V. Storia eruttiva
    Description: 2V. Struttura e sistema di alimentazione dei vulcani
    Description: 4V. Processi pre-eruttivi
    Description: 5V. Processi eruttivi e post-eruttivi
    Description: 6V. Pericolosità vulcanica e contributi alla stima del rischio
    Description: JCR Journal
    Keywords: GNSS ; resurgent caldera ; subsidence ; modelling ; degassing processes ; earthquakes ; 04.08. Volcanology ; 04.03. Geodesy ; 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 20
    Publication Date: 2022-01-11
    Description: Immersive virtual reality can potentially open up interesting geological sites to students, academics and others who may not have had the opportunity to visit such sites previously. We study how users perceive the usefulness of an immersive virtual reality approach applied to Earth Sciences teaching and communication. During nine immersive virtual reality-based events held in 2018 and 2019 in various locations (Vienna in Austria, Milan and Catania in Italy, Santorini in Greece), a large number of visitors had the opportunity to navigate, in immersive mode, across geological landscapes reconstructed by cutting-edge, unmanned aerial system-based photogrammetry techniques. The reconstructed virtual geological environments are specifically chosen virtual geosites, from Santorini (Greece), the North Volcanic Zone (Iceland), and Mt. Etna (Italy). Following the user experiences, we collected 459 questionnaires, with a large spread in participant age and cultural background. We find that the majority of respondents would be willing to repeat the immersive virtual reality experience, and importantly, most of the students and Earth Science academics who took part in the navigation confirmed the usefulness of this approach for geo-education purposes.
    Description: This research has been provided in the framework of the following projects: (i) the MIUR project ACPR15T4_00098–Argo3D (http://argo3d.unimib.it/ (accessed on 26 November 2021)); (ii) 3DTeLC Erasmus + Project 2017-1-UK01-KA203-036719 (http://www.3dtelc.com (accessed on 26 November 2021)); (iii) EGU 2018 Public Engagement Grant (https://www.egu.eu/outreach/peg/ (accessed on 26 November 2021)). Agisoft Metashape is acknowledged for photogrammetric data processing. This article is also an outcome of Project MIUR–Dipartimenti di Eccellenza 2018–2022. Finally, this paper is an outcome of the Virtual Reality lab for Earth Sciences—GeoVires lab (https://geovires.unimib.it/ (accessed on 26 November 2021)). The work supports UNESCO IGCP 692 ‘Geoheritage for Resilience’.
    Description: Published
    Description: 9
    Description: 1TM. Formazione
    Description: JCR Journal
    Keywords: immersive virtual reality ; geology; ; photogrammetry; ; education; ; Iceland; ; Santorini ; Etna ; 04.04. Geology ; 05.03. Educational, History of Science, Public Issues ; 05.04. Instrumentation and techniques of general interest ; 04.08. Volcanology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 21
    Publication Date: 2022-02-02
    Description: Volcanology, seismology and Earth Sciences in general, like all quantitative sciences, are increasingly dependent on the quantity and quality of data acquired. In recent dec-ades, a marked evolution has characterized Earth sciences towards a greater use of ana-lytical and numerical approaches, shifting these fields from the natural to the physical sciences. Understanding the physical behavior of active volcanoes and faults is critical to as-sess the hazards affecting the population living close to active volcano and seismic areas, and thus to mitigate the risks posed by those threats [1,2]. The knowledge of a physical process requires the acquisition of a huge amount of information (data) on that particular phenomenon. Today, different kinds of data record the processes that operate in volcanic and tec-tonic systems and provide insights that can lead to improved predictions of potential hazards, both immediate and long term. The geoscience community has collected an enormous wealth of data that require further analysis. The diversity and quantity of these geoscience data and collections continue to expand [3]. The increasing amount of data and the availability of new technologies and instru-mentation at an ever-greater rate open new frontiers and challenges for acquiring, trans-mitting, archiving, processing and analyzing the newly available datasets. Guo [4] pre-dicted growth for the general digital universe size of factor 10 from 2016 to 2025. Among all digital data, scientific data are those relevant to the observation of natural phenomena and characterized by non-repeatability, high uncertainty, high dimensionality and a high degree of computational complexity [4]. This means that scientific data need to be well preserved, due to the non-repeatability, and implies a parallel growth of processing capa-bilities to be well exploited. Cheng et al. [5] highlighted the striking growth of Earth Sci-ence data from molecular to astronomical scales and the increasing use of supercompu-ting tools for supporting geoscience research. The authors evidence how, with the contin-uously increasing availability of digital data, Earth Sciences are also turning from the tra-ditional question-driven or problem-driven approach, where scientists seek to find an-swers to known questions, to the new data-driven one where scientists apply a data dis-covery process that might find answers to still unknown questions. In agreement with Cheng et al. [5], we believe that new integrated multi-disciplinary knowledge systems and new data discovery techniques for handling and mining big data for knowledge discovery would spur the integration of transdisciplinary and mul-ti-dimensional Earth science data. Furthermore, this will help the transition from a nar-row focus on separate disciplines to a holistic, comprehensive and integrative focus of the different disciplines linked to the Earth Sciences. With this aim, for this special issue titled “Data Processing and Modeling on Volcan-ic and Seismic Areas”, we invited articles on all aspects of solid Earth Science that made use of data to analyze and model processes related to volcanoes or earthquakes. Manuscripts with various types of analyses, including volcanic ground deformation modeling, seismic swarm characterization and volcanic gas measurement, have been proposed and published. The collection provides an insight into the enormous need for increasingly complex data analysis and modeling techniques to try to describe the natural phenomena here considered. This special issue was introduced to collect the latest research on the processing and modeling of Earth Sciences data, and to address challenging problems with all topics re-lated to volcanoes and seismic areas. Various subjects have been addressed in this collec-tion, mainly on data processing for volcanic studies (three papers), tectonics (two papers) and one paper on data analysis of a new instrument to measure gases. The first contribution to this collection [6] reports the results of the processing and combination of high-rate and low-rate geodetic data for revealing the dynamics underly-ing violent volcanic eruptions at Mount Etna. This study evidences the wide spectrum of ground deformation produced by these phenomena, to be investigated, processed and modeled in order to generate a picture of the feeding system of the volcano and better un-derstand its dynamics and rates of magma transfer in the upper crust. Another contribution focuses on volcanoes [7]: the authors exploit 20 years of high temporal resolution satellite Thermal Infra-Red (TIR) data collected over three active vol-canoes (Etna, Shishaldin and Shinmoedake). They present the results of an analysis of this dataset performed through a preliminary RST (Robust Satellite Techniques) algorithm implementation to TIR data from the Advanced Spaceborne Thermal Emission and Re-flection Radiometer (ASTER). This approach ensures efficient identification and mapping of volcanic thermal features even of a low intensity level, which is also useful in the per-spective of an operational multi-satellite observing system. The contribution by Woohyun Son et al. [8] proposes specific depth-domain data processing of migration velocity analysis (MVA) of seismic data collected during a survey on a saline aquifer sediment in the Southern Continental Shelf of Korea. This analysis al-lowed the authors to identify and determine the precise depth of a basalt flow that could act as a cap rock for CO2 storage beneath the aquifer. The investigation, through the geo-logical model obtained from both time- and depth-domain processing, provides suitable information for locating the best drilling sites for CO2 injection, maximizing the storage volume. In volcanic areas, gases represent important physical evidence of volcanic processes that need to be measured. Parracino et al. [9] have shown how novel range-resolved DI-AL-Lidar (Differential Absorption Light Detection and Ranging) could herald a new era in the observation of long-term volcanic CO2 gases. An accurate and integrated analysis of different types of data such as GNSS, seismic and MT-InSAR, has led, in the work by Gatsios et al. [10], to a first account of deformation processes and their temporal evolution over recent years for Methana (Greece), thus providing initial information to feed into a volcano baseline hazard assessment and mon-itoring system. Seismic data are among the most important data to understand the dynamics of the Earth’s interior. A consistent analysis of a seismic swarm allowed Kostoglou et al. [11] to shed more light on the regional geodynamics of the Kefalonia Transform Fault Zone (Greece), and to follow the temporal evolution of the b-value to distinguish between fore-shock and aftershock behaviors.
    Description: Published
    Description: 10759
    Description: 6SR VULCANI – Servizi e ricerca per la società
    Description: JCR Journal
    Keywords: processing ; monitoring ; 04.08. Volcanology ; 05.01. Computational geophysics ; 05.06. Methods ; 04.06. Seismology
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  • 22
    Publication Date: 2022-10-24
    Description: We investigate crustal deformation within the upper plate of the Ionian Subduction Zone (ISZ) at different time scales by (i) refining geodetic rates of crustal extension from continuous Global Navigation Satellite System (GNSS) measurements and (ii) mapping sequence of Late Quaternary raised marine terraces tectonically deformed by the West Crati normal fault, in northern Calabria. This region experienced damaging earthquakes in 1184 (M 6.75) and 1854 (M 6.3), possibly on the E-dipping West Crati fault (WCF) which, however, is not unanimously considered to be a seismogenic source. We report geodetic measurements of extension and strain rates across the strike of the E-dipping WCF and throughout the northern Calabria obtained by using velocities from 18 permanent GNSS stations with a series length longer than 4.5 years. These results suggest that crustal extension may be seismically accommodated in this region by a few normal faults. Furthermore, by applying a synchronous correlation approach, we refine the chronology of understudied tectonically deformed palaeoshorelines mapped on the footwall and along the strike of the WCF, facilitating calculation of the associated fault-controlled uplift rates. Raised Late Quaternary palaeoshorelines are preserved on the footwall of the WCF indicating that “regional” uplift, likely related to the deformation associated either with the subduction or mantle upwelling processes, is affected by local footwall uplift. We show that GIS-based elevations of Late Quaternary palaeoshorelines, as well as temporally constant uplift rates, vary along the strike of the WCF, implying normal faulting activity through time. This suggests that (i) the fault slip rate governing seismic hazard has also been constant over the Late Quaternary, over multiple earthquake cycles, and (ii) our geodetically derived fault throw rate for the WCF is likely a more than reasonable value to be used over longer time scales for an improved seismic hazard assessment. Overall, we emphasize the importance of mapping crustal deformation within the upper plate above subduction zones to avoid unreliable interpretations relating to the mechanism controlling regional uplift.
    Description: Published
    Description: 5303
    Description: 2T. Deformazione crostale attiva
    Description: JCR Journal
    Keywords: Crustal Deformation ; Active Faults ; Marine terraces ; Earthquakes ; 04.04. Geology ; 04.03. Geodesy ; 04.07. Tectonophysics
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  • 23
    Publication Date: 2022-11-21
    Description: The ML 5.8 earthquake that hit the island of Crete on 27 September 2021 is analysed with InSAR (Interferometry from Synthetic Aperture Radar) and GNSS (Global Navigation Satellite System) data. The purpose of this work is to create a model with sufficient detail for the geophysical processes that take place in several kilometres below the earth’s surface and improve our ability to observe active tectonic processes using geodetic and seismic data. InSAR coseismic displacements maps show negative values along the LOS of ~18 cm for the ascending orbit and ~20 cm for the descending one. Similarly, the GNSS data of three permanent stations were used in PPK (Post Processing Kinematic) mode to (i) estimate the coseismic shifts, highlighting the same range of values as the InSAR, (ii) model the deformation of the ground associated with the main shock, and (iii) validate InSAR results by combining GNSS and InSAR data. This allowed us to constrain the geometric characteristics of the seismogenic fault and the slip distribution on it. Our model, which stands on a joint inversion of the InSAR and GNSS data, highlights a major rupture surface striking 214◦, dipping 50◦ NW and extending at depth from 2.5 km down to 12 km. The kinematics is almost dip-slip normal (rake −106◦), while a maximum slip of ~1.0 m occurred at a depth of ca. 6 km. The crucial though indirect role of inherited tectonic structures affecting the seismogenic crustal volume is also discussed suggesting their influence on the surrounding stress field and their capacity to dynamically merge distinct fault segments.
    Description: Published
    Description: 5783
    Description: 2T. Deformazione crostale attiva
    Description: 3T. Fisica dei terremoti e Sorgente Sismica
    Description: JCR Journal
    Keywords: SAR ; GNSS ; interferometry ; source modelling ; 27 September 2021 earthquake ; Crete system faults ; 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 24
    Publication Date: 2022-12-01
    Description: One of the strategies to detect the precursors of an eruption is to define the background dynamical state of a volcano for a prompt recognition of deviations from the basic condition. Mt. Vesuvius (Italy), currently in a quiescent state, is one of the most monitored volcanoes in the world, inciting multidisciplinary advanced studies. Hence an understanding of the links among the different monitored parameters is mandatory. In recent decades the joint analyses of ground tilt and seismicity have added to the understanding of the volcanos' activity. In this paper, we outline the first steps towards a comprehension of the link between Mt. Vesuvius earthquakes and co-seismic ground tilt, after excluding the contribution of other external forces acting on the ground, such as tides, landslides or exceptional meteorological phenomena. We used the seismicity with a duration magnitude ≥ 2.0 recorded at Mt. Vesuvius in the period 2018–2020 to estimate the source parameters and to calculate the associated static displacement. Then, we compared the ground inclination retrieved from the estimated seismic deformation with the long-term ground motion trend measured by tiltmeters. We found that in most cases the two vectors have a comparable size and direction.
    Description: Published
    Description: 12261
    Description: 2T. Deformazione crostale attiva
    Description: 3T. Fisica dei terremoti e Sorgente Sismica
    Description: 4V. Processi pre-eruttivi
    Description: JCR Journal
    Keywords: tilt ; earthquakes ; static displacement ; Mt. Vesuvius ; 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 25
    Publication Date: 2022-09-07
    Description: To increase seismic resilience is one of the challenges the developers of new technologies face to reduce seismic risk. We set up an augmented reality (AR) exhibition with which users’ curiosity was confronted with the opportunity to have a wealth of information on damaging earthquakes that could be a multimedia add-on to the plain “single-layer exhibit”. AR is an emergent technology developed to “augment” reality through various devices; it combines the real world with virtual items, such as images and videos. Our AR exhibition aims to: (i) show the effects of earthquakes even in cases of moderate magnitude; and (ii) promote preventive actions to reduce non-structural damage. It can be customized for different seismic scenarios. In addition, it offers a holistic approach to communicate problems and solutions—with the cost and degree of ease of execution for each solution—to reduce non-structural damage at home, school, and office. Our AR exhibition can do more than just a plain text or a preconceived video: it can trigger fruitful interaction between the presenters, or even the stand-alone poster, and the public. Such interactivity offers an easy engagement to people of all ages and cultural backgrounds. AR is, indeed, extremely flexible in raising recipients’ interest; moreover, it is an appealing tool for the digital native generations. The positive feedback received led us to conclude that this is an effective way to raise awareness and individual preparedness to seismic risk.
    Description: This study was co-financed by the European Commission’s Humanitarian Aid and Civil Protection (grant agreement ECHO/SUB/2015/718655/PREV28).
    Description: Published
    Description: 332
    Description: 5T. Sismologia, geofisica e geologia per l'ingegneria sismica
    Description: JCR Journal
    Keywords: Augmented Reality ; earthquakes ; non-structural damage ; seismic risk ; education ; 04.06. Seismology ; 05.06. Methods ; 05.08. Risk
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 26
    Publication Date: 2022-08-26
    Description: This article has been accepted for publication in Geophysical Journal International ©: The Authors 2022. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved. Uploaded in accordance with the publisher's self-archiving policy.
    Description: Defining the regional variability of minimum magnitude for earthquake detection is crucial for planning seismic networks. Knowing the earthquake detection magnitude values is fundamental for the optimal location of new stations and to select the priority for reactivating the stations of a seismic network in case of a breakdown. In general, the assessment of earthquake detection is performed by analysing seismic noise with spectral or more sophisticated methods. Further, to simulate amplitude values at the recording sites, spectral methods require knowledge of several geophysical parameters including rock density, S-wave velocity, corner frequency, quality factor, site specific decay parameter and so on, as well as a velocity model for the Earth's interior. The simulation results are generally expressed in terms of Mw and therefore a further conversion must be done to obtain the values of local magnitude (ML), which is the parameter commonly used for moderate and small earthquakes in seismic catalogues. Here, the relationship utilized by a seismic network to determine ML is directly applied to obtain the expected amplitude [in mm, as if it were recorded by a Wood–Anderson (WA) seismometer] at the recording site, without any additional assumptions. The station detection estimates are obtained by simply considering the ratio of the expected amplitude with respect to the background noise, also measured in mm. The seismic noise level for the station is estimated starting from four waveforms (each signal lasting 1 min) sampled at various times of the day for a period of one week. The proposed method is tested on Italian seismic events occurring in 2019 by using the locations of 16.879 earthquakes recorded by 374 stations. The first results indicate that by evaluating the station noise level with 5-s windows, a representative sample of the variability in expected noise level is generated for every station, even if only 4 min of signal per day over a week of recordings is used. The method was applied to define the detection level of the Italian National Seismic Network (RSN). The RSN detection level represents a reference for the definition and application of guidelines in the field of monitoring of subsurface industrial activities in Italy. The proposed approach can be successfully applied to define the current performance of a local seismic network (managed by private companies) and to estimate the expected further improvements, requested to fulfil the guidelines with the installation of new seismic stations. This method has been tested in Italy and can be reproduced wherever the local magnitude ML, based on synthetic WA records, is used.
    Description: Published
    Description: 1283–1297
    Description: 4T. Sismicità dell'Italia
    Description: JCR Journal
    Keywords: Time-series analysis ; Earthquake ground motions ; Seismic noise ; Induced seismicity ; 04.06. Seismology ; 05.04. Instrumentation and techniques of general interest
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  • 27
    Publication Date: 2021-03-15
    Description: In a recent work we computed the relative frequencies with which strong shocks (4.0≤Mw〈5.0), widely felt by the population were followed in the same area by potentially destructive main shocks (Mw≥5.0) in Italy. Assuming the stationarity of the seismic release properties, such frequencies can be tentatively used to estimate the probabilities of potentially destructive shocks after the occurrence of future strong shocks. This allows us to set up an alarm-based forecasting hypothesis related to strong foreshocks occurrence. Such hypothesis is tested retrospectively on the data of a homogenized seismic catalogue of the Italian area against a purely random hypothesis that simply forecasts the target main shocks proportionally to the space-time fraction occupied by the alarms. We compute the latter fraction in two ways a) as the ratio between the average time covered by the alarms in each area and the total duration of the forecasting experiment (60 years) and b) as the same ratio but weighted by the past frequency of occurrence of earthquakes in each area. In both cases the overall retrospective performance of our forecasting algorithm is definitely better than the random case. Considering an alarm duration of three months, the algorithm retrospectively forecasts more than 70% of all shocks with Mw5.5 occurred in Italy from 1960 to 2019 with a total space-time fraction covered by the alarms of the order of 2%. Considering the same space-time coverage, the algorithm is also able to retrospectively forecasts more than 40% of the first main shocks with Mw5.5 of the seismic sequences occurred in the same time interval. Given the good reliability of our results, the forecasting algorithm is set and ready to be tested also prospectively, in parallel to other ongoing procedures operating on the Italian territory.
    Description: This paper benefitted from funding provided by the European Union within the ambit of the H2020 project RISE (No. 821115), which in particular fully financed the PhD grant of one of the authors (E.B.).
    Description: Published
    Description: 1192–1206
    Description: 6T. Studi di pericolosità sismica e da maremoto
    Description: JCR Journal
    Keywords: Earthquake interaction ; Statistical seismology ; forecasting, ; prediction ; 04.06. Seismology
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  • 28
    Publication Date: 2021-03-24
    Description: On October 27, 2017, an Mw 4 earthquake occurred close to the municipality of Montesano sulla Marcellana, less than 10 km external to the concession of the largest European onshore hydrocarbon reservoir—the Val d’Agri oilfield (Southern Italy). Being a weak event located outside the extended monitoring domain of the industrial concession, the relevance of this earthquake and the possible links with the hydrocarbon exploitation were not extensively discussed. Actually, the analysis of shallow seismic events close to subsurface exploitation domains plays a significant role in the definition of key parameters in order to discriminate between natural, triggered, and induced seismicity, especially in tectonically active regions. The study of weak-to-moderate earthquakes can improve the characterization of the potentially destructive seismic hazard of this particular area, already struck by M 〉 6.5 episodes in the past. In this work, we analyze the source parameters of this Mw 4 earthquake by applying advanced seismological techniques to estimate the uncertainties derived from the moment tensor inversion and identify plausible directivity effects. The moment tensor is dominated by a NW–SE oriented normal faulting with a centroid depth of 14 km. A single ML 2.1 aftershock was recorded and used as the empirical Green’s function to calculate the apparent source time function for the mainshock. Apparent durations (in the range 0.11–0.21 s, obtained from S-waves) define an azimuthal pattern, which reveals an asymmetric bilateral rupture with 70% of the rupture propagation in the N310°Wdirection, suggesting a rupture plane dipping to the SW. Our results tally with the activation of a deeper fault segment associated with the Eastern Agri Fault System close to the basement as the origin of the Montesano earthquake. Finally, the Coulomb stress rate induced by depletion of the oilfield is calculated to quantify the trigger potential estimated for the Montesano earthquake yielding relatively low probabilities below 10%. Our analyses point toward the conclusion that the Mw 4 event was more likely due to the local natural tectonic stress, rather than induced or triggered by the long-term hydrocarbon extraction in the Val d’Agri oilfield.
    Description: Published
    Description: 617794
    Description: 3T. Fisica dei terremoti e Sorgente Sismica
    Description: JCR Journal
    Keywords: earthquake source ; induced seismicity ; directivity ; triggered earthquake ; Val d’Agri oilfield ; 04.06. Seismology
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  • 29
    Publication Date: 2021-05-12
    Description: In order to monitor temporal and spatial crustal activities associated with earthquakes, ground- and satellite-based monitoring systems have been installed in China since the 1990s. In recent years, the correlation between monitoring strain anomalies and local major earthquakes has been verified. In this study, we further evaluate the possibility of strain anomalies containing earthquake precursors by using Receiver Operating Characteristic (ROC) prediction. First, strain network anomalies were extracted in the borehole strain data recorded in Western China during 2010–2017. Then, we proposed a new prediction strategy characterized by the number of network anomalies in an anomaly window, Nano, and the length of alarm window, Talm. We assumed that clusters of network anomalies indicate a probability increase of an impending earthquake, and consequently, the alarm window would be the duration during which a possible earthquake would occur. The Area Under the ROC Curve (AUC) between true predicted rate, tpr, and false alarm rate, fpr, is measured to evaluate the efficiency of the prediction strategies. We found that the optimal strategy of short-term forecasts was established by setting the number of anomalies greater than 7 within 14 days and the alarm window at one day. The results further show the prediction strategy performs significantly better when there are frequent enhanced network anomalies prior to the larger earthquakes surrounding the strain network region. The ROC detection indicates that strain data possibly contain the precursory information associated with major earthquakes and highlights the potential for short-term earthquake forecasting.
    Description: National Natural Science Foundation of China under Grant 41974084 Ministry of Education, Culture, Sports, Science and Technology (MEXT) of Japan, under its observation and Research Program for Prediction of Earthquakes and Volcanic Eruptions.
    Description: Published
    Description: 515
    Description: 7T. Variazioni delle caratteristiche crostali e precursori sismici
    Description: JCR Journal
    Keywords: receiver operating characteristic ; a new prediction strategy ; frequent network anomalies ; prediction efficiency ; short-term earthquake forecasting ; 04.06. Seismology
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  • 30
    Publication Date: 2021-02-02
    Description: Abstract: In this paper we review and discuss the seismic method based on the analysis of seismic coda waves used in the last 10 years by the present authors and/or their co-workers, to produce separate images of intrinsic- and scattering attenuation in zones of peculiar geological interest (mainly volcanoes). Such separate attenuation images are considered by the scientific community as complementary to those from ordinary velocity-tomography and useful to improve the geological interpretation in volcanoes and in tectonically active zones. In this review we only list but do not discuss the most significative papers showing the images obtained, as we are focused to review the method and not the interpretation of data analysis. For sake of completeness, we anyway show also a new analysis applied to data from Stromboli volcano. We thus first introduce the physical model describing the seismogram Energy Envelope (derived from the solution of the Energy Transport integral Equation) and discuss its asymptotic approximations (Diffusion- and Single-scattering model). Then, we describe a numerical method to heuristically calculate the Sensitivity Kernels for the propagation of the scattered waves in the assumption of isotropic scattering. We attribute to these Sensitivity Kernels the physical meaning of probability that for a single source-receiver couple the measured attenuation parameters can be associated with the space coordinates. Based on this definition, the attenuation image can be obtained mapping the estimated attenuation parameters onto the zone under study weighting with the Sensitivity Kernels. We further discuss how to estimate the uncertainties associated with the results and report the list of the papers describing the (separated) scattering- and intrinsic-attenuation structures investigated using this approach.
    Description: Published
    Description: id304
    Description: 1T. Struttura della Terra
    Description: JCR Journal
    Keywords: seismic scattering ; seismic imaging ; sensitivity kernels ; seismic attenuation ; 04.06. Seismology
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  • 31
    Publication Date: 2021-03-24
    Description: The 2016–17 central Italy earthquake sequence began with the first mainshock near the town of Amatrice on August 24 (MW 6.0), and was followed by two subsequent large events near Visso on October 26 (MW 5.9) and Norcia on October 30 (MW 6.5), plus a cluster of 4 events with MW 〉 5.0 within few hours on January 18, 2017. The affected area had been monitored before the sequence started by the permanent Italian National Seismic Network (RSNC), and was enhanced during the sequence by temporary stations deployed by the National Institute of Geophysics and Volcanology and the British Geological Survey. By the middle of September, there was a dense network of 155 stations, with a mean separation in the epicentral area of 6–10 km, comparable to the most likely earthquake depth range in the region. This network configuration was kept stable for an entire year, producing 2.5 TB of continuous waveform recordings. Here we describe how this data was used to develop a large and comprehensive earthquake catalogue using the Complete Automatic Seismic Processor (CASP) procedure. This procedure detected more than 450,000 events in the year following the first mainshock, and determined their phase arrival times through an advanced picker engine (RSNI-Picker2), producing a set of about 7 million P- and 10 million S-wave arrival times. These were then used to locate the events using a non-linear location (NLL) algorithm, a 1D velocity model calibrated for the area, and station corrections and then to compute their local magnitudes (ML). The procedure was validated by comparison of the derived data for phase picks and earthquake parameters with a handpicked reference catalogue (hereinafter referred to as ‘RefCat’). The automated procedure takes less than 12 hours on an Intel Core-i7 workstation to analyse the primary waveform data and to detect and locate 3000 events on the most seismically active day of the sequence. This proves the concept that the CASP algorithm can provide effectively real-time data for input into daily operational earthquake forecasts, The results show that there have been significant improvements compared to RefCat obtained in the same period using manual phase picks. The number of detected and located events is higher (from 84,401 to 450,000), the magnitude of completeness is lower (from ML 1.4 to 0.6), and also the number of phase picks is greater with an average number of 72 picked arrival for a ML = 1.4 compared with 30 phases for RefCat using manual phase picking. These propagate into formal uncertainties of ± 0.9km in epicentral location and ± 1.5km in depth for the enhanced catalogue for the vast majority of the events. Together, these provide a significant improvement in the resolution of fine structures such as local planar structures and clusters, in particular the identification of shallow events occurring in parts of the crust previously thought to be inactive. The lower completeness magnitude provides a rich data set for development and testing of analysis techniques of seismic sequences evolution, including real-time, operational monitoring of b-value, time-dependent hazard evaluation and aftershock forecasting.
    Description: Published
    Description: 555–571
    Description: 3T. Fisica dei terremoti e Sorgente Sismica
    Description: JCR Journal
    Keywords: 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 32
    Publication Date: 2021-04-13
    Description: Recently, a new strain rate map of Italy and the surrounding areas has been obtained by processing data acquired by the persistent scatterers (PS) of the synthetic aperture radar interferome- try (InSAR) satellites—ERS and ENVISAT—between 1990 and 2012. This map clearly shows that there is a link between the strain rate and all the shallow earthquakes (less than 15 km deep) that occurred from 1990 to today, with their epicenters being placed only in high strain rate areas (e.g., Emilia plain, NW Tuscany, Central Apennines). However, the map also presents various regions with high strain rates but in which no damaging earthquakes have occurred since 1990. One of these regions is the Apennine sector, formed by Sannio and Irpinia. This area represents one of the most important seismic districts with a well-known and recorded seismicity from Roman times up to the present day. In our study, we merged historical records with new satellite techniques that allow for the precise determination of ground movements, and then derived physical dimensions, such as strain rate. In this way, we verified that in Irpinia, the occurrence of new strong shocks—forty years after one of the strongest known seismic events in the district that occurred on the 23 November 1980, measuring Mw 6.8—is still a realistic possibility. The reason for this is that, from 1990, only areas characterized by high strain rates have hosted significant earthquakes. This picture has been also confirmed by analyzing the historical catalog of events with seismic completeness for magnitude M ≥ 6 over the last four centuries. It is easy to see that strong seismic events with magnitude M ≥ 6 generally occurred at a relatively short time distance between one another, with a period of 200 years without strong earthquakes between the years 1732 and 1930. This aspect must be considered as very important from various points of view, particularly for civil protection plans, as well as civil engineering and urban planning development.
    Description: Published
    Description: 168
    Description: 4T. Sismicità dell'Italia
    Description: JCR Journal
    Keywords: Irpinia ; seismic hazard ; strain rate ; GNSS ; InSAR ; earthquake ; 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 33
    Publication Date: 2021-05-12
    Description: Earthquake Environmental Effects (EEEs) are a common occurrence following moderate to strong seismic events. EEEs are described in literary sources even for earthquakes that occurred hundreds of years ago, but their potential for hazard assessment is not fully exploited. Here we analyze five earthquakes occurred in the Southern Apennines (Italy) between 1688 and 1980, to assess if EEEs are reliable indicators of the effects caused by past earthquakes. We investigate the spatial distribution of EEEs and their ability to repeatedly occur at the same place, and we quantitatively compare the macroseismic fields expressed in terms of damage-based intensity (MCS: Mercalli–Cancani–Sieberg) to the Environmental Scale Intensity (ESI) macroseismic field, derived from an intensity attenuation relation. We computed the field “ESI-MCS”, showing that results are consistent when comparing different seismic events and that ESI values are higher in the first ca. 10 km from the epicenter, while at distances greater than 20 km MCS values are higher than ESI. Our research demonstrates that (i) EEEs offer a detailed picture of earthquake effects in the near field and (ii) the reappraisal of literary sources under a modern perspective may provide improved input parameters that are useful for seismic hazard assessment.
    Description: Published
    Description: 332
    Description: 5SR TERREMOTI - Convenzioni derivanti dall'Accordo Quadro decennale INGV-DPC
    Description: JCR Journal
    Keywords: Earthquake Environmental Effect; Apennines; ESI scale; intensity attenuation ; 04.04. Geology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 34
    Publication Date: 2021-05-12
    Description: erratum paper
    Description: Published
    Description: 1090-1092
    Description: 1T. Struttura della Terra
    Description: JCR Journal
    Keywords: Theoretical seismology ; Seismic attenuation ; Seismic noise ; Surface waves ; Free oscillations ; Seismic interferometry ; 04.06. Seismology ; 04.01. Earth Interior
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 35
    Publication Date: 2021-01-29
    Description: The first 5.3 years of magnetic data from three Swarm satellites have been systematically analyzed, and possible co-seismic magnetic disturbances in the ionosphere were investigated just a few minutes after the occurrence of large earthquakes. We preferred to limit the investigation to a subset of earthquakes selected in function of depth and magnitude. After a systematic inspection of the available data around (in time and space) the seismic events, we found 12 Swarm satellite tracks with co-seismic disturbances possibly produced by ten earthquakes from Mw5.6 to Mw6.9. The distance of the satellite to the earthquake epicenter corresponds to the measured distance-time arrival of the disturbance from the surface to the ionosphere, confirming that the identified disturbances are most likely produced by the seismic events. Secondly, we found a good agreement with a model that combined a propagation of the disturbance to the F2 ionospheric layer with an acoustic gravity wave at a velocity of about (2.2 0.3) km/s and a second faster phenomenon that transmits the disturbance from F2 layer to the Swarm satellite with a velocity of about (16 3) km/s as an electromagnetic scattering propagation.
    Description: Published
    Description: 1166
    Description: 7T. Variazioni delle caratteristiche crostali e precursori sismici
    Description: JCR Journal
    Keywords: coseismic phenomena ; ionospheric phenomena ; 01.02. Ionosphere ; 04.05. Geomagnetism ; 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 36
    Publication Date: 2021-04-14
    Description: The scaling of earthquake parameters with seismic moment and its interpretation in terms of self- similarity is still debated in the literature. We address this question by examining a worldwide compilation of corner frequency-based and elastic rebound theory (ERT)-based fault slip, area and stress drop values for earthquakes ranging in magnitude from -0.7 to 7.8. We find that corner frequency estimates of slip (and stress drop) scale differently than those inferred from the ERT approach, where the latter deviates from the generally accepted constant stress drop behavior of so- called self-similar scaling models. We also find that average slips from finite-source models are consistent with corner frequency scaling, whereas peak slip values are more consistent with the ERT scaling. The different scaling of corner frequency- and ERT-based estimates of slip and stress drop with earthquake size is interpreted in terms of heterogeneity of the rupture process. ERT-based estimates of stress drop decrease with seismic moment suggesting a self-affine behavior. Despite the inferred heterogeneity at all scales, we do not observe a clear effect on the Brune stress drop scaling with earthquake size.
    Description: Published
    Description: 1771–1781
    Description: 2T. Deformazione crostale attiva
    Description: JCR Journal
    Keywords: Earthquake dynamics ; Earthquake source observations ; Dynamics and mechanics of faulting ; 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 37
    Publication Date: 2021-01-22
    Description: We present a structural study on the tectonic windows of Giffoni and Campagna, located in the western sector of the southern Apennines (Italy). We analyzed thrusts, folds, and related minor deformation structures. Here, a major in-sequence E-verging thrust fault juxtaposes Meso-Cenozoic successions of the Apennine Platform (Picentini Mts unit) and the Lagonegro-Molise Basin (Frigento unit). However, out-of-sequence thrusts duplicated the tectonic pile with the interposition of the upper Miocene wedge-top basin deposits of the Castelvetere Group. We reconstructed the orogenic evolution of these two tectonic windows, including five deformation phases. The first (D1) was related to the in-sequence thrusting with minor thrusts and folds, widespread both in the footwall and the hanging wall. A subsequent extension (D2) has formed normal faults crosscutting the D1 thrusts and folds. All structures were subsequently affected by two shortening stages (D3 and D4), which also deformed the upper Miocene wedge top basin deposits of the Castelvetere Group. We interpreted the D3–D4 structures as related to an out-of-sequence thrust system defined by a main frontal E-verging thrust and lateral ramps characterized by N and S vergences. Low-angle normal faults were formed in the hanging wall of the major thrusts. Out-of-sequence thrusts are observed in the whole southern Apennines, recording a crustal shortening event that occurred in the late Messinian–early Pliocene. Finally, we suggest that the two tectonic windows are the result of the formation of an E–W trending regional antiform, associated with a late S-verging back-thrust, that has been eroded and crosscut by normal faults (D5) in the Early Pleistocene. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.
    Description: Published
    Description: 405
    Description: 2TR. Ricostruzione e modellazione della struttura crostale
    Description: JCR Journal
    Keywords: Out-of-sequence thrust ; Southern Apennines ; 04.04. Geology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 38
    Publication Date: 2021-05-12
    Description: We have constructed a 3-D shear wave velocity (Vs) model for the crust and uppermost mantle beneath the Middle East using Rayleigh wave records obtained from ambient-noise cross-correlations and regional earthquakes. We combined one decade of data collected from 852 permanent and temporary broad-band stations in the region to calculate group-velocity dispersion curves. A compilation of 〉54 000 ray paths provides reliable group-velocity measurements for periods between 2 and 150 s. Path-averaged group velocities calculated at different periods were inverted for 2-D group-velocity maps. To overcome the problem of heterogeneous ray coverage, we used an adaptive grid parametrization for the group-velocity tomographic inversion. We then sample the period-dependent group-velocity field at each cell of a predefined grid to generate 1-D group-velocity dispersion curves, which are subsequently inverted for 1-D Vs models beneath each cell and combined to approximate the 3-D Vs structure of the area. The Vs model shows low velocities at shallow depths (5–10 km) beneath the Mesopotamian foredeep, South Caspian Basin, eastern Mediterranean and the Black Sea, in coincidence with deep sedimentary basins. Shallow high-velocity anomalies are observed in regions such as the Arabian Shield, Anatolian Plateau and Central Iran, which are dominated by widespread magmatic exposures. In the 10–20 km depth range, we find evidence for a band of high velocities (〉4.0 km s–1) along the southern Red Sea and Arabian Shield, indicating the presence of upper mantle rocks. Our 3-D velocity model exhibits high velocities in the depth range of 30–50 km beneath western Arabia, eastern Mediterranean, Central Iranian Block, South Caspian Basin and the Black Sea, possibly indicating a relatively thin crust. In contrast, the Zagros mountain range, the Sanandaj-Sirjan metamorphic zone in western central Iran, the easternmost Anatolian plateau and Lesser Caucasus are characterized by low velocities at these depths. Some of these anomalies may be related to thick crustal roots that support the high topography of these regions. In the upper mantle depth range, high-velocity anomalies are obtained beneath the Arabian Platform, southern Zagros, Persian Gulf and the eastern Mediterranean, in contrast to low velocities beneath the Red Sea, Arabian Shield, Afar depression, eastern Turkey and Lut Block in eastern Iran. Our Vs model may be used as a new reference crustal model for the Middle East in a broad range of future studies.
    Description: Published
    Description: 1349-1365
    Description: 1T. Struttura della Terra
    Description: JCR Journal
    Keywords: 04.01. Earth Interior ; 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 39
    Publication Date: 2021-04-30
    Description: On 24 August 2016, a Mw 6.0 earthquake started a damaging seismic sequence in central Italy. The historical center of Amatrice village reached the XI degree (MCS scale) but the high vulnerability alone could not explain the heavy damage. Unfortunately, at the time of the earthquake only AMT station, 200 m away from the downtown, recorded the mainshock, whereas tens on temporary stations were installed afterwards. We propose a method to simulate the ground motion affecting Amatrice, using the FFT amplitude recorded at AMT, which has been modified by the standard spectral ratio (SSR) computed at 14 seismic stations in downtown. We tested the procedure by comparing simulations and recordings of two later mainshocks (Mw 5.9 and Mw 6.5), underlining advantages and limits of the technique. The strong motion variability of simulations was related to the proximity of the seismic source, accounted for by the ground motion at AMT, and to the peculiar site effects, described by the transfer function at the sites. The largest amplification characterized the stations close to the NE hill edge and produced simulated values of intensity measures clearly above one standard deviation of the GMM expected for Italy, up to 1.6 g for PGA.
    Description: The grant of A.T. is funded by INGV and Department of Sciences, Roma Tre University (MIUR-Italy Dipartimenti di Eccellenza, Art.1, Commi 314-337 Legge 232/2016).
    Description: Published
    Description: 186
    Description: 5T. Sismologia, geofisica e geologia per l'ingegneria sismica
    Description: JCR Journal
    Keywords: strong ground motion ; earthquake simulation ; near-source ; Amatrice earthquake ; seismic sequence ; site effects ; 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 40
    Publication Date: 2021-05-12
    Description: We present a structural study on late Miocene-early Pliocene out-of-sequence thrusts affecting the southern Apennine orogenic belt. The analyzed structures are exposed in the Campania region (southern Italy). Here, thrusts bound the N-NE side of the carbonate ridges that form the regional mountain backbone. In several outcrops, the Mesozoic carbonates are superposed onto the unconformable wedge-top basin deposits of the upper Miocene Castelvetere Group, providing constraints to the age of the activity of this thrusting event. Moreover, a 4-km-long N-S oriented electrical resistivity tomography profile, carried out along the Caserta mountains, sheds light on the structure of this thrust system in an area where it is not exposed. Further information was carried out from a tunnel excavation that allowed us to study some secondary fault splays. The kinematic analysis of out-of-sequence major and minor structures hosted both in the hanging wall (Apennine Platform carbonates) and footwall (Castelvetere Group deposits and Lagonegro-Molise Basin units) indicates the occurrence of two superposed shortening directions, about E-W and N-S, respectively. We associated these compressive structures to an out-of-sequence thrusting event defined by frontal thrusts verging to the east and lateral ramp thrusts verging to the north and south. We related the out-of-sequence thrusting episode to the positive inversion of inherited normal faults located in the Paleozoic basement. These envelopments thrust upward to crosscut the allochthonous wedge, including, in the western zone of the chain, the upper Miocene wedge-top basin deposits.
    Description: Published
    Description: 301
    Description: 2TR. Ricostruzione e modellazione della struttura crostale
    Description: JCR Journal
    Keywords: southern Apennines ; out-of-sequence thrust ; wedge-top basin ; electrical resistivity tomography ; 04.04. Geology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 41
    Publication Date: 2021-09-21
    Description: Passive seismic interferometry has become very popular in recent years in explorationgeophysics. However, it has not been widely applied in marine exploration. The purpose of thisstudy is to investigate the internal structure of a quasi-amagmatic portion of the Southwest IndianRidge by interferometry and to examine the performance and reliability of interferometry in marineexplorations. To reach this goal, continuous vertical component recordings from 43 ocean bottomseismometers were analyzed. The recorded signals from 200 station pairs were cross-correlated inthe frequency domain. The Bessel function method was applied to extract phase–velocity dispersioncurves from the zero crossings of the cross-correlations. An average of all the dispersion curveswas estimated in a period band 1–10 s and inverted through a conditional neighborhood algorithmwhich led to the final 1D S-wave velocity model of the crust and upper mantle. The obtained S-wavevelocity model is in good agreement with previous geological and geophysical studies in the regionand also in similar areas. We find an average crustal thickness of 7 km with a shallow layer of lowshear velocities and high Vp/Vs ratio. We infer that the uppermost 2 km are highly porous and maybe strongly serpentinized.
    Description: Published
    Description: 2811
    Description: 1T. Struttura della Terra
    Description: JCR Journal
    Keywords: 04.06. Seismology ; 04.01. Earth Interior
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 42
    Publication Date: 2021-12-22
    Description: The comparison between crustal stress and surface strain azimuthal patterns has provided new insights into several complex tectonic settings worldwide. Here, we performed such a comparison for Egypt taking into account updated datasets of seismological and geodetic observations. In north-eastern Egypt, the stress field shows a fan-shaped azimuthal pattern with a WNW–ESE orientation on the Cairo region, which progressively rotated to NW–SE along the Gulf of Aqaba. The stress field shows a prevailing normal faulting regime, however, along the Sinai/Arabia plate boundary it coexists with a strike–slip faulting one (σ1 ≅ σ2 〉 σ3), while on the Gulf of Suez, it is characterized by crustal extension occurring on near-orthogonal directions (σ1 〉 σ2 ≅ σ3). On the Nile Delta, the maximum horizontal stress (SHmax) pattern shows scattered orientations, while on the Aswan region, it has a WNW–ESE strike with pure strike–slip features. The strain-rate field shows the largest values along the Red Sea and the Sinai/Arabia plate boundary. Crustal stretching (up to 40 nanostrain/yr) occurs on these areas with WSW–ENE and NE–SW orientations, while crustal contraction occurs on northern Nile Delta (10 nanostrain/yr) and offshore (~35 nanostrain/yr) with E–W and N–S orientations, respectively. The comparison between stress and strain orientations over the investigated area reveals that both patterns are near-parallel and driven by the same large-scale tectonic processes.
    Description: This research was partially funded by the Programa Operativo FEDER Andalucía 2014-2020—A call made by the University of Jaén 2018.
    Description: Published
    Description: 1398
    Description: 2T. Deformazione crostale attiva
    Description: JCR Journal
    Keywords: strain ; stress ; GNSS ; Egypt ; 04.03. Geodesy ; 04. Solid Earth ; 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 43
    Publication Date: 2021-12-23
    Description: A comparative analysis of geodetic versus seismic moment-rate estimations makes it possible to distinguish between seismic and aseismic deformation, define the style of deformation, and also to reveal potential seismic gaps. This analysis has been performed for Egypt where the present-day tectonics and seismicity result from the long-lasting interaction between the Nubian, Eurasian, and Arabian plates. The data used comprises all available geological and tectonic information, an updated Poissonian earthquake catalog (2200 B.C.–2020 A.D.) including historical and instrumental datasets, a focal-mechanism solutions catalog (1951–2019), and crustal geodetic strains from Global Navigation Satellite System (GNSS) data. The studied region was divided into ten (EG-01 to EG-10) crustal seismic sources based mainly on seismicity, focal mechanisms, and geodetic strain characteristics. The delimited seismic sources cover the Gulf of Aqaba–Dead Sea Transform Fault system, the Gulf of Suez–Red Sea Rift, besides some potential seismic active regions along the Nile River and its delta. For each seismic source, the estimation of seismic and geodetic moment-rates has been performed. Although the obtained results cannot be considered to be definitive, among the delimited sources, four of them (EG-05, EG-06, EG-08, and EG-10) are characterized by low seismic-geodetic moment-rate ratios (〈20%), reflecting a prevailing aseismic behavior. Intermediate moment-rate ratios (from 20% to 60%) have been obtained in four additional zones (EG-01, EG-04, EG-07, and EG-09), evidencing how the seismicity accounts for a minor to a moderate fraction of the total deformational budget. In the other two sources (EG-02 and EG-03), high seismic-geodetic moment-rates ratios (〉60%) have been observed, reflecting a fully seismic deformation
    Description: This research has been partially funded in the frame of the Programa Operativo FEDER Andalucía 2014–2020-call made by the University of Jaén, 2018.
    Description: Published
    Description: 7836
    Description: 2T. Deformazione crostale attiva
    Description: JCR Journal
    Keywords: Seismicity ; GNSS ; Strain ; seismic hazard ; Egypt ; 04. Solid Earth ; 04.03. Geodesy ; 04.06. Seismology
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  • 44
    Publication Date: 2021-12-24
    Description: This article has been accepted for publication in Geophysical Journal International ©: The Authors 2021. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved. Uploaded in accordance with the publisher's self-archiving policy.
    Description: Ambient-noise records from the AlpArray network are used to measure Rayleigh wave phase velocities between more than 150,000 station pairs. From these, azimuthally anisotropic phase-velocity maps are obtained by applying the Eikonal tomography method. Several synthetic tests are shown to study the bias in the Ψ2 anisotropy. There are two main groups of bias, the first one caused by interference between refracted/reflected waves and the appearance of secondary wavefronts that affect the phase travel-time measurements. This bias can be reduced if the amplitude field can be estimated correctly. Another source of error is related to the incomplete reconstruction of the travel-time field that is only sparsely sampled due to the receiver locations. Both types of bias scale with the magnitude of the velocity heterogeneities. Most affected by the spurious Ψ2 anisotropy are areas inside and at the border of low-velocity zones. In the isotropic velocity distribution, most of the bias cancels out if the azimuthal coverage is good. Despite the lack of resolution in many parts of the surveyed area, we identify a number of anisotropic structures that are robust: in the central Alps, we find a layered anisotropic structure, arc-parallel at midcrustal depths and arc-perpendicular in the lower crust. In contrast, in the eastern Alps, the pattern is more consistently E-W oriented which we relate to the eastward extrusion. The northern Alpine forleand exhibits a preferential anisotropic orientation that is similar to SKS observations in the lowermost crust and uppermost mantle.
    Description: German Science Foundation (SPP-2017, Project Ha 2403/21-1); Swiss National Science Foundation SINERGIA Project CRSII2-154434/1 (Swiss-AlpArray); Progetto Pianeta Dinamico, finanziamento MUR-INGV, Task S2 – 2021
    Description: Published
    Description: 151–170
    Description: 1T. Struttura della Terra
    Description: JCR Journal
    Keywords: Seismic anisotropy ; Seismic interferometry ; Seismic tomography ; Wave propagation ; Continental tectonics: compressional ; 04.01. Earth Interior ; 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 45
    Publication Date: 2021-12-15
    Description: This article has been accepted for publication in Geophysical Journal International ©: The Authors 2022. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved. Uploaded in accordance with the publisher's self-archiving policy.
    Description: To understand the seismotectonics and the seismic hazard of the study sector of the Northern Apennines (Italy), one of the most important earthquakes of magnitude Mw = 6.5 which struck the Lunigiana and Garfagnana areas (Tuscany) on 7 September 1920 should be studied. Given the early instrumental epoch of the event, neither geometric and kinematic information on the fault-source nor its fault-plane solution were available. Both areas were candidates for hosting the source fault and there was uncertainty between a normal fault with Apenninic direction or an anti-Apenninic strike-slip. We retrieved 11 focal parameters (including the fault-plane solution) of the 1920 earthquake. Only macroseismic intensity information (from 499 inhabited centres) through the KF-NGA inversion technique was used. This technique uses a Kinematic model of the earthquake source and speeds up the calculation by a Genetic Algorithm with Niching. The result is a pure dip-slip focal solution. The intrinsic ambiguities of the KF-NGA method (±180° on the rake angle; choice of the fault plane between the two nodal planes) were solved with field and seismotectonic evidence. The earthquake was generated by a normal fault (rake angle = 265° ± 8°) with an Apennine direction (114° ± 5°) and dipping 38° ± 6° towards SW. The likely candidate for hosting the source-fault in 1920 is the Compione-Comano fault that borders the NE edge of the Lunigiana graben. The KF-NGA algorithm proved to be invaluable for studying the kinematics of early instrumental earthquakes and allowed us to uniquely individuate, for the first time ever, the seismogenic source of the 1920 earthquake. Our findings have implications in hazard computation and seismotectonic contexts.
    Description: Published
    Description: 1465–1477
    Description: 4T. Sismicità dell'Italia
    Description: JCR Journal
    Keywords: Inverse theory ; Body waves ; Earthquake source observations ; Seismicity and tectonics ; Dynamics: seismotectonics ; Fractures, faults, and high strain deformation zones ; 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 46
    Publication Date: 2021-11-26
    Description: Seismicity-based earthquake forecasting models have been primarily studied and developed over the past twenty years. These models mainly rely on seismicity catalogs as their data source and provide forecasts in time, space, and magnitude in a quantifiable manner. In this study, we presented a technique to better determine future earthquakes in space based on spatially smoothed seismicity. The improvement’s main objective is to use foreshock and aftershock events together with their mainshocks. Time-independent earthquake forecast models are often developed using declustered catalogs, where smaller-magnitude events regarding their mainshocks are removed from the catalog. Declustered catalogs are required in the probabilistic seismic hazard analysis (PSHA) to hold the Poisson assumption that the events are independent in time and space. However, as highlighted and presented by many recent studies, removing such events from seismic catalogs may lead to underestimating seismicity rates and, consequently, the final seismic hazard in terms of ground shaking. Our study also demonstrated that considering the complete catalog may improve future earthquakes’ spatial forecast. To do so, we adopted two different smoothed seismicity methods: (1) the fixed smoothing method, which uses spatially uniform smoothing parameters, and (2) the adaptive smoothing method, which relates an individual smoothing distance for each earthquake. The smoothed seismicity models are constructed by using the global earthquake catalog with Mw ≥ 5.5 events. We reported progress on comparing smoothed seismicity models developed by calculating and evaluating the joint log-likelihoods. Our resulting forecast shows a significant information gain concerning both fixed and adaptive smoothing model forecasts. Our findings indicate that complete catalogs are a notable feature for increasing the spatial variation skill of seismicity forecasts.
    Description: Published
    Description: 10899
    Description: 6T. Studi di pericolosità sismica e da maremoto
    Description: JCR Journal
    Keywords: seismic hazard ; Smoothed Seismicity Approach ; global seismic catalog ; aftershocks ; 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 47
    Publication Date: 2023-11-21
    Description: This article has been accepted for publication in Geophysical Journal International ©:The Author(s) 2021. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.Uploaded in accordance with the publisher's self-archiving policy. All rights reserved.
    Description: On 24 August 2016 at 01:36 UTC a ML6.0 earthquake struck several villages in central Italy, among which Accumoli, Amatrice and Arquata del Tronto. The earthquake was recorded by about 350 seismic stations, causing 299 fatalities and damage with macroseismic intensities up to 11. The maximum acceleration was observed at Amatrice station (AMT) reaching 916 cm s–2 on E–W component, with epicentral distance of 15 km and Joyner and Boore distance to the fault surface (RJB) of less than a kilometre. Motivated by the high levels of observed ground motion and damage, we generate broad-band seismograms for engineering purposes by adopting a hybrid method. To infer the low frequency seismograms, we considered the kinematic slip model by Tinti et al . The high frequency seismograms were produced using a stochastic finite-fault model approach based on dynamic corner-frequency. Broadband synthetic time-series were therefore obtained by merging the low and high frequency seismograms. Simulated hybrid ground motions were compared both with the observed ground motions and the ground-motion prediction equations (GMPEs), to explore their performance and to retrieve the region-specific parameters endorsed for the simulations. In the near-fault area we observed that hybrid simulations have a higher capability to detect near source effects and to reproduce the source complexity than the use of GMPEs. Indeed, the general good consistency found between synthetic and observed ground motion (both in the time and frequency domain), suggests that the use of regional-specific source scaling and attenuation parameters together with the source complexity in hybrid simulations improves ground motion estimations. To include the site effect in stochastic simulations at selected stations, we tested the use of amplification curves derived from HVRSs (horizontal-to-vertical response spectra) and from HVSRs (horizontal-to-vertical spectral ratios) rather than the use of generic curves according to NTC18 Italian seismic design code. We generally found a further reduction of residuals between observed and simulated both in terms of time histories and spectra.
    Description: Published
    Description: 1753–1779
    Description: 6T. Studi di pericolosità sismica e da maremoto
    Description: JCR Journal
    Keywords: 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 48
    Publication Date: 2023-11-16
    Description: This article has been accepted for publication in Geophysical Journal International ©:The Author(s) 2020. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.Uploaded in accordance with the publisher's self-archiving policy. All rights reserved
    Description: This study describes a deep convolutional neural network (CNN) based technique for the prediction of intensity measurements (IMs) of ground shaking. The input data to the CNN model consists of multistation 3C broadband and accelerometric waveforms recorded during the 2016 Central Italy earthquake sequence for M $\ge$ 3.0. We find that the CNN is capable of predicting accurately the IMs at stations far from the epicenter and that have not yet recorded the maximum ground shaking when using a 10 s window starting at the earthquake origin time. The CNN IM predictions do not require previous knowledge of the earthquake source (location and magnitude). Comparison between the CNN model predictions and the predictions obtained with Bindi et al. (2011) GMPE (which require location and magnitude) has shown that the CNN model features similar error variance but smaller bias. Although the technique is not strictly designed for earthquake early warning, we found that it can provide useful estimates of ground motions within 15-20 sec after earthquake origin time depending on various setup elements (e.g., times for data transmission, computation, latencies). The technique has been tested on raw data without any initial data pre-selection in order to closely replicate real-time data streaming. When noise examples were included with the earthquake data, the CNN was found to be stable predicting accurately the ground shaking intensity corresponding to the noise amplitude.
    Description: Published
    Description: 1379–1389
    Description: 8T. Sismologia in tempo reale
    Description: JCR Journal
    Keywords: Physics - Geophysics; Physics - Geophysics ; 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 49
    Publication Date: 2023-11-16
    Description: This article has been accepted for publication in Geophysical Journal International ©:The Author(s) 2020. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.Uploaded in accordance with the publisher's self-archiving policy. All rights reserved.
    Description: In volcanoes, topography, shallow heterogeneity and even shallow morphology can substan- tially modify seismic coda signals. Coda waves are an essential tool to monitor eruption dynamics and model volcanic structures jointly and independently from velocity anomalies: it is thus fundamental to test their spatial sensitivity to seismic path effects. Here, we apply the Multiple Lapse Time Window Analysis (MLTWA) to measure the relative importance of scattering attenuation vs absorption at Mount St Helens volcano before its 2004 erup- tion. The results show the characteristic dominance of scattering attenuation in volcanoes at lower frequencies (3–6 Hz), while absorption is the primary attenuation mechanism at 12 and 18 Hz. Scattering attenuation is similar but seismic absorption is one order of magnitude lower than at open-conduit volcanoes, like Etna and Kilauea, a typical behaviour of a (rela- tively) cool magmatic plumbing system. Still, the seismic albedo (measuring the ratio between seismic energy emitted and received from the area) is anomalously high (0.95) at 3 Hz. A radiative-transfer forward model of far- and near-field envelopes confirms this is due to strong near-receiver scattering enhancing anomalous phases in the intermediate and late coda across the 1980 debris avalanche and central crater. Only above this frequency and in the far-field diffusion onsets at late lapse times. The scattering and absorption parameters derived from MLTWA are used as inputs to construct 2-D frequency-dependent bulk sensitivity kernels for the S-wave coda in the multiple-scattering (using the Energy Transport Equations—ETE) and diffusive (AD, independent of MLTWA results) regimes. At 12 Hz, high coda-attenuation anomalies characterize the eastern side of the volcano using both kernels, in spatial correla- tion with low-velocity anomalies from literature. At 3 Hz, the anomalous albedo, the forward modelling, and the results of the tomographic imaging confirm that shallow heterogeneity beneath the extended 1980 debris-avalanche and crater enhance anomalous intermediate and late coda phases, mapping shallow geological contrasts. We remark the effect this may have on coda-dependent source inversion and tomography, currently used across the world to image and monitor volcanoes. At Mount St Helens, higher frequencies and deep borehole data are necessary to reconstruct deep volcanic structures with coda waves.
    Description: Scottish Alliance for Geosciences Environment and Society and the Kleinman Grant for Volcano Research
    Description: Published
    Description: 169-188
    Description: 1T. Struttura della Terra
    Description: 2V. Struttura e sistema di alimentazione dei vulcani
    Description: 3IT. Calcolo scientifico
    Description: JCR Journal
    Keywords: NorthAmerica ; Wave scattering and diffraction. ; Codawaves ; Seismicattenuation ; Seismic tomography ; Volcano seismology ; 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 50
    Publication Date: 2023-11-14
    Description: This article has been accepted for publication in Geophysical Journal International ©:The Author(s) 2020. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.Uploaded in accordance with the publisher's self-archiving policy. All rights reserved.
    Description: We compile a data set of Rayleigh-wave phase velocities between pairs of stations, based on teleseismic events located on the same great circle as the two stations. We validate our observations against dispersion estimates based on ambient-noise cross correlations at the same station pairs. Discrepancies between the results of the two methods can in principle be explained by deviations in the wave propagation path between earthquake and receivers, due to lateral heterogeneity in the Earth’s structure, but the latter effect has, so far, not been precisely quantified nor corrected for. We implement an algorithm to measure the arrival angle of earthquake-generated surface waves and correct the dispersion measurements accordingly. Application to a data set from the Central-Western Mediterranean shows that the arrival-angle correction almost entirely accounts for the discrepancy in question, decreasing significantly the velocity bias for a wide range of periods.
    Description: Published
    Description: 1838–1844
    Description: 1T. Struttura della Terra
    Description: JCR Journal
    Keywords: 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 51
    Publication Date: 2022-06-22
    Description: Silicic calderas are volcanic systems whose unrest evolution is more unpredictable than other volcano types because they often do not culminate in an eruption. Their complex structure strongly influences the post-collapse volcano-tectonic evolution, usually coupling volcanism and ground deformation. Among such volcanoes, the Campi Flegrei caldera (southern Italy) is one of the most studied. Significant long- and short-term ground deformations characterize this restless volcano. Several studies performed on the marinecontinental succession exposed in the central sector of the Campi Flegrei caldera provided a reconstruction of ground deformation during the last 15 kyr. However, considering that over one-third of the caldera is presently submerged beneath the Pozzuoli Gulf, a comprehensive stratigraphic on-land-offshore framework is still lacking. This study aims at reconstructing the offshore succession through analysis of high-resolution single and multichannel reflection seismic profiles and correlates the resulting seismic stratigraphic framework with the stratigraphy reconstructed on-land. Results provide new clues on the causative relations between the intra-caldera marine and volcaniclastic sedimentation and the alternating phases of marine transgressions and regressions originated by the interplay between ground deformation and sea-level rise. The volcano-tectonic reconstruction, provided in this work, connects the major caldera floor movements to the large Plinian eruptions of Pomici Principali (12 ka) and Agnano Monte Spina (4.55 ka), with the onset of the first post-caldera doming at ~10.5 ka. We emphasize that ground deformation is usually coupled with volcanic activity, which shows a self-similar pattern, regardless of its scale. Thus, characterizing the long-term deformation history becomes of particular interest and relevance for hazard assessment and definition of future unrest scenarios.
    Description: Published
    Description: 855-882
    Description: 1V. Storia eruttiva
    Description: JCR Journal
    Keywords: offshore stratigraphy ; seismic units ; La Starza succession ; volcanism, ; 04.08. Volcanology ; 04.04. Geology ; 04.07. Tectonophysics
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 52
    Publication Date: 2020-10-26
    Description: This paper presents a detailed geological map at the 1:20,000 scale of the Tocomar basin in the Central Puna (north-western Argentina), which extends over an area of about 80 km2 and displays the spatial distribution of the Quaternary deposits and the structures that cover the Ordovician basement and the Tertiary sedimentary and volcanic units. The new dataset includes litho-facies descriptions, stratigraphic and structural data and new 234U/230Th ages for travertine rocks. The new reconstructed stratigraphic framework, along with the structural analysis, has revealed the complex evolution of a small extensional basin including a period of prolonged volcanic activity with different eruptive centres and styles. The geological map improves the knowledge of the geology of the Tocomar basin and the local interplay between orogen-parallel thrusts and orogen-oblique fault systems. This contribution represents a fundamental support for in depth research and also for encouraging geothermal exploration and exploitation in the Puna Plateau region.
    Description: Published
    Description: id 5492
    Description: 1TR. Georisorse
    Description: JCR Journal
    Keywords: geothermal exploration ; U/Th dating ; Southern Central Andes ; central Puna ; 04. Solid Earth ; 04.04. Geology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 53
    Publication Date: 2020-05-25
    Description: We explore the three‐dimensional structure of the 2016–2017 Central Italy sequence using ~34,000 ML ≥ 1.5 earthquakes that occurred between August 2016 and January 2018. We applied cross‐correlation and double‐difference location methods to waveform and parametric data routinely produced at the Italian National Institute of Geophysics and Volcanology. The sequence activated an 80 km long system of normal faults and near‐horizontal detachment faults through the MW 6.0 Amatrice, the MW 5.9 Visso, and the MW 6.5 Norcia mainshocks and aftershocks. The system has an average strike of N155°E and dips 38°–55° southwestward and is segmented into 15–30 km long faults individually activated by the cascade of MW ≥ 5.0 shocks. The two main normal fault segments, Mt. Vettore‐Mt. Bove to the North and Mt. della Laga to the South, are separated by an NNE‐SSW‐trending lateral ramp of the Sibillini thrust, a regional structure inherited from the previous compressional tectonic phase putting into contact diverse lithologies with different seismicity patterns. Space‐time reconstruction of the fault system supports a composite rupture scenario previously proposed for the MW 6.5 Norcia earthquake, where the rupture possibly propagated also along an oblique portion of the Sibillini thrust. This dissected set of normal fault segments is bounded at 8–10 km depth by a continuous 2 km thick seismicity layer of extensional nature slightly dipping eastward and interpreted as a shear zone. All three mainshocks in the sequence nucleated along the high‐angle planes at significant distance from the shear zone, thus complicating the interpretation of the mechanisms driving strain partitioning between these structures.
    Description: Published
    Description: e2019JB018440
    Description: 3T. Sorgente sismica
    Description: JCR Journal
    Keywords: normal fault ; shear zone ; fault segmentation ; apennines ; 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 54
    Publication Date: 2020-07-08
    Description: The response of continental forelands to subduction and collision is a widely investigated topic in geodynamics. The deformation occurring within a foreland shared by two opposite‐verging chains, however, is uncommon and poorly understood. The Apulia Swell in the southern end of the Adria microplate (Africa‐Europe plate boundary, central Mediterranean Sea) represents one of these cases, as it is the common foreland of the SW verging Albanides‐Hellenides and the NE verging Southern Apennines merging into the SSE verging Calabrian Arc. We investigated the internal deformation of the Apulia Swell using multiscale geophysical data: multichannel seismic profiles recording up to 12‐s two‐way time (TWT) for a consistent image of the upper crust; high‐resolution multichannel seismic profiles, high‐resolution multibeam bathymetry, and CHIRP profiles acquired by R/V OGS Explora to constrain the Quaternary geological record. The results of our analyses characterize the geometry of the South Apulia Fault System (SAFS), a 100‐km‐long and 12‐km‐wide structure attesting an extensional (and possibly transtensional) response of the foreland to the two contractional fronts. The SAFS consists of two NW‐SE right‐stepping master faults and several secondary structures. The SAFS activity spans from the Early Pleistocene through the Holocene, as testified by the bathymetric and high‐resolution seismic data, with long‐term slip rates in the range of 0.2–0.4 mm/yr. Considering the position within an area with few or none other active faults in the surroundings, the dimension, and the activity rates, the SAFS can be a candidate causative fault of the 20 February 1743, M 6.7, earthquake.
    Description: Italian Ministry for Education, University, and Research (MIUR), Premiale 2014 D. M. 291 03/05/2016.
    Description: Published
    Description: e2020TC006116
    Description: 2T. Deformazione crostale attiva
    Description: 2TR. Ricostruzione e modellazione della struttura crostale
    Description: JCR Journal
    Keywords: active tectonics ; apulia ; south apulia fault system ; 1743 earthquake ; marine geology ; stable continental region ; ionian sea ; active faults ; subsurface geology ; seismic interpretation ; 04.04. Geology ; 04.07. Tectonophysics ; 04.02. Exploration geophysics
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 55
    Publication Date: 2021-01-25
    Description: Tsunami deposits present an important archive for understanding tsunami histories and dynamics. Most research in this field has focused on onshore preserved remains, while the offshore deposits have received less attention. In 2009, during a coring campaign with theItalian Navy Magnaghi, four 1 m long gravity cores (MG cores) were sampled from the northern part of Augusta Bay, along a transect in 60 to 110 m water depth. These cores were taken in the same area where a core (MS06) was collected in 2007 about 2.3 km offshore Augusta at a water depth of 72 m below sea level. Core MS06 consisted of a 6.7 m long sequence that included 12 anomalous intervals interpreted as the primary effect of tsunami backwash waves in the last 4500 years. In this study, tsunami deposits were identified, based on sedimentology and displaced benthic foraminifera (as for core MS06) reinforced by X-ray fluorescence data. Two erosional surfaces (L1 and L2) were recognized coupled with grain size increase, abundant Posidonia oceanica seagrass remains and a significant amount of Nubecularia lucifuga, an epiphytic sessile benthic foraminifera considered to be transported from the inner shelf. The occurrence of Ti/Ca and Ti/Sr increments, coinciding with peaks in organic matter (Mo inc/coh) suggests terrestrial run-off coupled with an input of organic matter. The L1 and L2 horizons were attributed to two distinct historical tsunamis (AD 1542 and AD 1693) by indirect age-estimation methods using 210Pb profiles and the comparison of Volume Magnetic Susceptibility data between MG cores and MS06 cores. One most recent bioturbated horizon (Bh), despite not matching the above listed interpretative features, recorded an important palaeoenvironmental change that may correspond to the AD 1908 tsunami. These findings reinforce the value of offshore sediment records as an underutilized resource for the identification of past tsunamis.
    Description: Published
    Description: 1553-1576
    Description: 6T. Studi di pericolosità sismica e da maremoto
    Description: JCR Journal
    Keywords: Eastern Sicily ; tsunami ; foraminifera ; sedimentology ; XRF core scanning ; 04.04. Geology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 56
    Publication Date: 2017-04-04
    Description: The three volcanoes that are the object of this paper show different types of activity that are representative of the large variety of volcanism present in the Central Mediterranean area. Etna and Stromboli are sub-aerial volcanoes, with significant part of their structure under the sea, while the Marsili Seamount is submerged, and its activity is still open to debate. The study of these volcanoes can benefit from multi-parametric observations from the seafloor. Each volcano was studied with a different kind of observation system. Stromboli seismic recordings are acquired by means of a single Ocean Bottom Seismometer (OBS). From these data, it was possible to identify two different magma chambers at different depths. At Marsili Seamount, gravimetric and seismic signals are recorded by a battery-powered multi-disciplinary observatory (GEOSTAR). Gravimetric variations and seismic Short Duration Events (SDE) confirm the presence of hydrothermal activity. At the Etna observation site, seismic signals, water pressure, magnetic field and acoustic echo intensity are acquired in real-time thanks to a cabled multi-disciplinary observatory (NEMO-SN1 ). This observatory is one of the operative nodes of the European Multidisciplinary Seafloor and water-column Observatory (EMSO; www.emso-eu.org) research infrastructure. Through a multidisciplinary approach, we speculate about deep Etna sources and follow some significant events, such as volcanic ash diffusion in the seawater.
    Description: Published
    Description: 298
    Description: 3A. Ambiente Marino
    Description: JCR Journal
    Description: restricted
    Keywords: EMSO ; volcanic ash clouds ; seafloor observatories ; stand-alone monitoring systems ; volcano seismology ; 03. Hydrosphere::03.04. Chemical and biological::03.04.08. Instruments and techniques ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 57
    Publication Date: 2017-04-04
    Description: Different procedures were used to analyze a comprehensive time series of nighttime thermal infrared images acquired from October 2006 to June 2013 by a permanent station at Pisciarelli (Campi Flegrei, Italy). The methodologies were aimed at the detection and quantification of possible spatiotemporal changes in the ground-surface thermal features of an area affected by diffuse degassing. Long-term infrared time series images were processed without taking into account atmospheric conditions and emissivity estimations. The data obtained were compared with the trends of independent geophysical and geochemical parameters, which suggested that long-term temporal variations of the surface maximum temperatures were governed by the dynamics of the deeper hydrothermal system. Analogously, the dynamics of the shallow hydrothermal system are likely to control the short-period thermal oscillations that overlie the long-term thermal signals. The map of the yearly rates of temperature change shows temperature increases clustered in the thermal anomalous area of the infrared images, without evidence of modifications to the extension of the anomaly or of growth of new areas with significant thermal emission. This suggests that in the present state, the heat transfer is mainly due to hot gas emission through preexisting fractures and vents. Our data indicate that the comprehensive picture of the spatiotemporal evolution of the thermal features of the hydrothermal sites obtained by long-term infrared monitoring can provide useful information toward refining physical and conceptual models, as well as improving surveillance of active volcanoes.
    Description: The TIR monitoring system was partially funded by the 2000–2006 National Operating Programme and by the Italian Civil Protection Department in the framework of the 2004–2006 agreement with the Istituto Nazionale di Geofisica e Vulcanologia.
    Description: Published
    Description: 812–826
    Description: 2V. Dinamiche di unrest e scenari pre-eruttivi
    Description: 5V. Sorveglianza vulcanica ed emergenze
    Description: JCR Journal
    Description: restricted
    Keywords: Thermal Infrared Monitoring ; Campi Flegrei ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 58
    Publication Date: 2017-04-04
    Description: A series of computer microtomography experiments are reported which were performed by using a third-generation synchrotron radiation source on volcanic rocks from various active hazardous volcanoes in Italy and other volcanic areas in the world. The applied technique allowed the internal structure of the investigated material to be accurately imaged at the micrometer scale and three-dimensional views of the investigated samples to be produced as well as three-dimensional quantitative measurements of textural features. Thegeometryof thevesicle (gas-filledvoid) network in volcanic products of both basaltic and trachytic compositions were particularly focused on, as vesicle textures are directly linked to the dynamics of volcano degassing. This investigation provided novel insights into modes of gas exsolution, transport and loss in magmas that were not recognized in previous studies using solely conventional two- dimensional imaging techniques. The results of this study are important to understanding the behaviour of volcanoes and can be combined with other geosciences disciplines to forecast their future activity.
    Description: In press
    Description: 2.3. TTC - Laboratori di chimica e fisica delle rocce
    Description: JCR Journal
    Description: reserved
    Keywords: high-resolution three-dimensional imaging ; X-ray computed microtomography ; volcanic eruptions ; volcanic rock textures ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 59
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    Unknown
    Wiley
    In:  Hoboken, NJ, 633 pp., Wiley, vol. 16B, no. 2, pp. 125-169, (ISBN 0-471-26610-8)
    Publication Date: 2003
    Keywords: Textbook of mathematics ; Data analysis / ~ processing ; Modelling ; software ; manual ; computer ; algebra ; symbolic ; mathematics
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  • 60
    facet.materialart.
    Unknown
    Wiley
    In:  New York, Wiley, vol. 2, no. XVI:, pp. 1-14, (ISBN 0-08-043751-6)
    Publication Date: 1986
    Keywords: Data analysis / ~ processing
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  • 61
    facet.materialart.
    Unknown
    Wiley
    In:  Chichester, Wiley, vol. 231, no. 3, pp. 2-203, (ISBN 0-470-02298-1)
    Publication Date: 1982
    Keywords: Data analysis / ~ processing ; Correlation ; Seismic stratigraphy ; Seismics (controlled source seismology)
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  • 62
    facet.materialart.
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    Wiley
    In:  New York, 2nd Edition, 709 pp., Wiley, vol. 75, no. 2, pp. 2-203, (ISBN: 3-7643-7143-9)
    Publication Date: 1981
    Keywords: Correlation ; Data analysis / ~ processing ; fit ; Textbook of mathematics
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