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  • Articles  (4,872)
  • Chemistry  (4,706)
  • 04.06. Seismology  (166)
  • Analytical Chemistry and Spectroscopy
  • Animals
  • 2020-2024  (167)
  • 1940-1944  (4,705)
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  • 1
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    The Community Stress-Drop Validation Study—Part I: Source, Propagation, and Site Decomposition of Fourier Spectra (2023)
    Seismological Society of America
    Details
    Publication Date: 2023-10-03
    Description: In part 1, we run multiple GIT decomposition for different choices of model assumptions, namely three different window duration for Fourier calculation, two different parametrization of the attenuation, two different site constraints. We also considered different source models (Brune, Boatwright, Brune with kappa_source) and different approaches to estimate uncertainties of source parameters (i.e., considering the covariance matrix, Monte Carlo sampling of the residual distribution, model selection with threshold based on F-test).
    Description: As part of the community stress-drop validation study initiative, we apply a spectral decomposition approach to isolate the source spectra of 556 events occurred during the 2019 Ridgecrest sequence (Southern California). We perform multiple decompositions by introducing alternative choices for some processing and model assumptions, namely: three different S-wave window durations (i.e., 5 s, 20 s, and variable between 5 and 20 s); two attenuation models that account differently for depth dependencies; and two different site amplification constraints applied to restore uniqueness of the solution. Seismic moment and corner frequency are estimated for the Brune and Boatwright source models, and an extensive archive including source spectra, site amplifications, attenuation models, and tables with source parameters is disseminated as the main product of the present study. We also compare different approaches to measure the precision of the parameters expressed in terms of 95% confidence intervals (CIs). The CIs estimated from the asymptotic standard errors and from Monte Carlo resampling of the residual distribution show an almost one-to-one correspondence; the approach based on model selection by setting a threshold for misfit chosen with an F-ratio test is conservative compared to the approach based on the asymptotic standard errors. The uncertainty analysis is completed in the companion article in which the outcomes from this work are used to compare epistemic uncertainty with precision of the source parameters.
    Description: Published
    Description: 1980–1991
    Description: 3T. Fisica dei terremoti e Sorgente Sismica
    Description: JCR Journal
    Keywords: source parameters ; GIT ; uncertainties ; moment magnitude ; corner frequency ; 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 2
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    Graph neural networks for multivariate time series regression with application to seismic data (2023)
    Springer
    Details
    Publication Date: 2023-08-29
    Description: Machine learning, with its advances in deep learning has shown great potential in analyzing time series. In many scenarios, however, additional information that can potentially improve the predictions is available. This is crucial for data that arise from e. g., sensor networks that contain information about sensor locations. Then, such spatial information can be exploited by modeling it via graph structures, along with the sequential (time series) information. Recent advances in adapting deep learning to graphs have shown potential in various tasks. However, these methods have not been adapted for time series tasks to a great extent. Most attempts have essentially consolidated around time series forecasting with small sequence lengths. Generally, these architectures are not well suited for regression or classification tasks where the value to be predicted is not strictly depending on the most recent values, but rather on the whole length of the time series. We propose TISER-GCN, a novel graph neural network architecture for processing, in particular, these long time series in a multivariate regression task. Our proposed model is tested on two seismic datasets containing earthquake waveforms, where the goal is to predict maximum intensity measurements of ground shaking at each seismic station. Our findings demonstrate promising results of our approach—with an average MSE reduction of 16.3%—compared to the best performing baselines. In addition, our approach matches the baseline scores by needing only half the input size. The results are discussed in depth with an additional ablation study.
    Description: Interreg North-West Europe program (Interreg NWE), project Di-Plast - Digital Circular Economy for the Plastics Industry (NWE729). INGV Pianeta Dinamico 2021 Tema 8 SOME (CUP D53J1900017001) funded by Italian Ministry of University and Research “Fondo finalizzato al rilancio degli investimenti delle amministrazioni centrali dello Stato e allo sviluppo del Paese, legge 145/2018.
    Description: Published
    Description: 317–332
    Description: 8T. Sismologia in tempo reale e Early Warning Sismico e da Tsunami
    Description: JCR Journal
    Keywords: Graph neural networks ; Time series ; Sensors ; Convolutional neural networks ; Regression ; Earthquake ground motion ; Seismic network ; 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 3
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    Looking for undocumented earthquake effects: a probabilistic analysis of Italian macroseismic data (2023)
    Egu-Copernicus
    Details
    Publication Date: 2023-08-29
    Description: A methodology to detect local incompleteness of macroseismic intensity data at the local scale is presented. In particular, the probability that undocumented effects actually occurred at a site is determined by considering intensity prediction equations (in their probabilistic form) integrated by observations relative to known events documented at surrounding sites. The outcomes of this analysis can be used to investigate how representative and known the seismic histories of localities are (i.e., the list of documented effects through time). The proposed approach is applied to the Italian area. The analysis shows that, at most of the considered sites, the effects of intensity ≥ 6 should most probably have occurred at least once, but they are not contained in the current version of the Italian macroseismic databases. In a few cases, instead, the lack of data may concern higher intensity levels (i.e., ≥ 8). The geographical distribution of potentially lost information reflects the heterogeneity of the seismic activity over the Italian territory.
    Description: Published
    Description: 1805–1816
    Description: 4T. Sismicità dell'Italia
    Description: JCR Journal
    Keywords: Macroseismology ; 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 4
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    Inferring the depth and magnitude of pre-instrumental earthquakes from intensity attenuation curves (2023)
    Egu-Copernicus
    Details
    Publication Date: 2023-08-29
    Description: The Italian historical earthquake record is among the richest worldwide; as such it allows for the development of advanced techniques for retrieving quantitative information by calibration with recent earthquakes. Building on a pilot elaboration of northern Italian earthquakes, we developed a procedure for determining the hypocentral depth of all Italian earthquakes from macroseismic intensity data alone. In a second step the procedure calculates their magnitude, taking into account the inferred depth. Hypocentral depth exhibits substantial variability countrywide but has so far received little attention: pre-instrumental earthquakes were routinely “flattened” at the upper-crustal level (∼10 km), on the grounds that the calculation of hypocentral depth is heavily dependent on the largely unknown local propagation properties. We gathered a learning set of 42 earthquakes documented by reliable instrumental data and by numerous macroseismic intensity observations. We observe (1) that within 50 km from the epicenter the ground motion attenuation rate is primarily controlled by hypocentral depth and largely independent of magnitude, (2) that within this distance the fluctuations in crustal attenuation properties are negligible countrywide, and (3) that knowing both the depth and the expected epicentral intensity makes it possible to estimate a reliable magnitude.
    Description: INGV DPC, 2019–2021 agreement; All. A, WP 7
    Description: Published
    Description: 1007–1028
    Description: 4T. Sismicità dell'Italia
    Description: 5T. Sismologia, geofisica e geologia per l'ingegneria sismica
    Description: JCR Journal
    Keywords: hypocentral depth ; magnitude ; macroseismology ; pre-instrumental earthquakes ; 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 5
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    Technical documentation of SEISMOFAULTS.EU: the IT infrastructure employed by the European Databases of Seismogenic Faults (EDSF) installation (2023)
    Details
    Publication Date: 2023-10-03
    Description: SEISMOFAULTS.EU is the IT infrastructure designed and implemented to publish datasets that are part of the European Databases of Seismogenic Faults (EDSF) installation hosted by the Istituto Nazionale di Geofisica e Vulcanologia. It consists of carefully selected and configured hardware and software in order to ensure a reliable, and secure service. The implemented backup solutions and continuous monitoring of the entire platform at various levels safeguard the system from disruptions due to various types of possible malfunctions. The main functionalities of SEISMOFAULTS.EU include the publication of datasets of seismogenic sources of the European and Mediterranean area through the standard web services developed by the Open Geospatial Consortium. Websites related to the same datasets as well as web services related to sibling projects, are also published through the infrastructure. Following government recommendations for public administration, most of the software used in the platform has an open­source license. The main software applications involved in web services publishing are PostgreSQL/PostGIS and GeoServer. SEISMOFAULTS.EU was designed under the auspices of EPOS, Thematic Core Service Seismology, and actively contributed to it by integrating datasets on seismogenic faults in the Euro­Mediterranean area into the EPOS Integrated Core Service ­ Central hub platform. The combination of efforts between EPOS and SEISMOFAULTS.EU strengthens the scientific geoscience community in coordinating efforts aimed at advancing knowledge in the field of seismology and the study of seismogenic sources and earthquake hazard analyses.
    Description: Istituto Nazionale di Geofisica e Vulcanologia
    Description: Published
    Description: 4IT. Banche dati
    Keywords: EPOS ; Seismogenic faults ; web services ; 04.06. Seismology ; 05.02. Data dissemination
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: report
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  • 6
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    Database spettrale del rumore sismico (1994—2003) alle stazioni della rete euro-mediterranea MedNet (2023)
    Details
    Publication Date: 2023-10-04
    Description: Istituto Nazionale di Geofisica e Vulcanologia
    Description: Published
    Description: 1IT. Reti di monitoraggio e sorveglianza
    Keywords: Seismic Noise at VBB seismic stations ; Mediterranean Seismic Network (MedNet) ; 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: web product
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  • 7
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    Criteri per individuazione di anomalie nel segnale registrato dalle stazioni della Rete Sismica Nazionale (2023)
    INGV - ONT
    Details
    Publication Date: 2023-10-11
    Description: La qualità del segnale prodotto dalle stazioni sismiche in ingresso nelle sale di monitoraggio o archiviato nei database, riveste notevole importanza ai fini di una corretta analisi dei sismogrammi, in particolare per una corretta stima della magnitudo. Un potente strumento di verifica della qualità è l’analisi spettrale nelle sue varie forme. Il pacchetto SQLX produce vari tipi di rappresentazioni grafiche: medie spettrali settimanali, mensili ed annuali, distribuzione del livello di rumore sismico in funzione della frequenza su una data finestra temporale (anche annuale), spettrogrammi h24 mediati su una settimana, un mese o un anno, diagrammi del livello di potenza di frequenze campione ecc. Un’attenta osservazione dei diagrammi, specie se confrontati con figure standard, guida ad individuare vari tipi di anomalie del segnale che possono dipendere da vari fattori, molto diversi gli uni dagli altri. A volte l’anomalia è causata da malfunzionamenti del sismometro, a volte da disturbi elettronici nel digitalizzatore/acquisitore, a volte da problemi o interferenze nella trasmissione del dato, altre volte da errori nel database ossia nelle tabelle dei metadati associati ad una stazione. Questi ultimi sono i casi in cui è possibile porre rimedio senza costi di missioni operative ma correggendo i dati in un database. A titolo di esempio, la figura rappresenta il livello di rumore sismico in funzione della frequenza, registrato nell’arco di un anno alla stazione LADO (S.Nicola dell’Alto, KR). Sono riportate in grigio scuro anche le curve di minimo e alto rumore sismico, rispettivamente Low Noise Model o LNM e High Noise Model o HNM. La zona colorata mostra invece il livello di rumore rappresentato come Densità di Potenza Spettrale o PSD dell’accelerazione ed i colori la probabilità in un anno di trovare quel valore (il giallo o il verde indicano valori più frequenti). Nell’intervallo tra 0.1 e 0.5 Hz il rumore risulta troppo basso per essere realistico, circa 20 dB inferiore al modello di minimo. Inoltre la forma del diagramma somiglierebbe molto alla forma tipica di un diagramma di rumore sismico se fosse tutta traslata verso l’alto di circa 20 dB. E’ evidente un errore nella Funzione di Risposta strumentale e quasi sicuramente tale errore è limitato ad una costante moltiplicativa (sensibilità). Questo inficia il calcolo della magnitudo a causa dell’errato valore di sensibilità e in questo caso la sottostima è di circa un punto di magnitudo ML (20 dB negli spetti di Potenza = fattore 10 nell’Ampiezza del sismogramma). Nella casistica sopra menzionata, verranno illustrati criteri per l’individuazione delle più evidenti anomalie.
    Description: Unpublished
    Description: Roma, via di Vigna Murata 605
    Description: 1IT. Reti di monitoraggio e sorveglianza
    Keywords: Rumore Sismico ; Spettri di Potenza SQLX ; Power Spectral Density (PSD) ; Probability Density Function (PDF) ; 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: Oral presentation
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  • 8
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    Reti neurali per individuare anomalie nel segnale delle stazioni RSN (2023)
    INGV - ONT
    Details
    Publication Date: 2023-10-11
    Description: Le reti neurali si stanno rivelando utili anche nelle discipline geofisiche ed in particolare quando si devono eseguire classificazioni di grandi moli di dati. I vari diagrammi SQLX (spettri di rumore, spettrogrammi ecc.) sono un importante strumento di analisi della qualità del segnale sismico in ingresso nelle sale operative INGV e/o archiviato. Grazie ad essi si possono individuare malfunzionamenti nelle stazioni o più in generale errori (anche di sensibilità/amplificazione) nel segnale sismico, errori che possono dipendere da vari fattori. Non potendo controllare “manualmente” diagrammi di circa 500 stazioni della RSN, oltre 3000 diagrammi, stiamo testando una procedura che utilizza l'intelligenza artificiale per automatizzare un’analisi preliminare che consenta poi all’analista di focalizzarsi solo su un numero limitato di stazioni “sospette”, già selezionate dalla procedura. In particolare, abbiamo eseguito il training di una rete neurale “profonda” che impara a classificare le immagini. Abbiamo eseguito il processo di apprendimento utilizzando 150 diagrammi di rumore standard (classificati preliminarmente “buoni”) e 150 classificati “anomali”. Durante la fase di apprendimento, il gruppo di appartenenza di ciascun diagramma (detto anche label) deve essere specificato come dato di input. Dopo aver eseguito il training, la rete neurale è in grado di classificare altri diagrammi (“buoni” e anomali) ossia di capire a quale gruppo indicato nel training appartiene un segnale che la rete non ha mai analizzato prima. Nel test eseguito, il sistema ha riconosciuto correttamente la classe di appartenenza dei diagrammi (buono/anomalo) nel 95% dei casi. La figura rappresenta la fase di apprendimento della rete neurale (linee blu). Durante tale fase, alcuni diagrammi sono riservati alla “validazione”: in altre parole, questi diagrammi non sono utilizzati nell’algoritmo matematico iterativo di apprendimento della rete neurale, ma soltanto per controllare l’accuratezza della rete anche su dati non utilizzati. L’accuratezza dei dati di validazione è mostrata dalla linea tratteggiata nera. Ai piedi del diagramma sono riportate alcune informazioni sulla procedura che impiega meno di 2 minuti per analizzare 300 diagrammi spettrali. In questa prima fase abbiamo usato solo le stazioni con sismometri a Larga Banda (canali HH*). Questo perché i diagrammi di tali stazioni sono simili tra loro e molto diversi da quelli delle stazioni a corto periodo. In altre parole abbiamo applicato la procedura a circa il 60% delle stazioni della RSN. Stiamo attualmente studiando come allargare l’analisi alle stazioni a corto periodo.
    Description: Unpublished
    Description: Roma, via di Vigna Murata 605
    Description: 1IT. Reti di monitoraggio e sorveglianza
    Keywords: Spettri di Potenza SQLX ; Power Spectral Density (PSD) ; Probability Density Function (PDF or PPSD) ; Rumore sismico ; Reti Neurali ; Convolutional Neural Network ; 04.06. Seismology ; 05.01. Computational geophysics ; 05.04. Instrumentation and techniques of general interest
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: Oral presentation
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  • 9
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    CRISP: an archive for the site characterization of permanent Italian seismic stations (2023)
    Springer
    Details
    Publication Date: 2023-10-11
    Description: Set of data and metadata that characterize a site hosting a seismic station
    Description: In this paper we describe an advanced database for the site characterization of seismic stations, named “CRISP—Caratterizzazione della RIsposta sismica dei Siti Permanenti della rete sismica” (http:// crisp. ingv. it, quoted with https:// doi. org/ 10. 13127/ crisp), designed for the Italian National Seismic Network (Rete Sismica Nazionale, RSN, operated by Istituto Nazionale di Geofisica e Vulcanologia). For each site, CRISP collects easily accessible station information, such as position, type(s) of instrumentation, instrument housing, thematic map(s) and descriptive attributes (e.g., geological characteristics, etc.), seismic analysis of recordings, and available geophysical investigations (shear-wave velocity [VS] profile, non-linear decay curve). The archive also provides key proxy indicators derived from the available data, such as the time-averaged shear-wave velocity of the upper 30 m from the surface ( VS30) and site and topographic classes according to the different seismic codes. Standardized procedures have been applied as motivated by the need for a homogenous set of information for all the stations. According to European Plate Observing System infrastructural objectives for the standardization of seismological data, CRISP is integrated into pre-existing INGV instrument infrastructures, shares content with the Italian Accelerometric Archive, and complies map information about the stations, as well as local geology, through web services managed by Istituto Superiore per la Protezione e la Ricerca Ambientale. The design of the CRISP archive allows the database to be continually updated and expanded whenever new data are available from the scientific community, such as the ones related to new seismic stations, map information, geophysical surveys, and seismological analyses.
    Description: Published
    Description: 2415 - 2439
    Description: 5T. Sismologia, geofisica e geologia per l'ingegneria sismica
    Description: JCR Journal
    Keywords: Site effects ; Site characterization ; Permanent seismic station ; Italian National Seismic Network ; Database ; 04.06. Seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 10
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    Stick-slip vs. stable sliding fault behaviour: A case-study using a multidisciplinary approach in the volcanic region of Mt. Etna (Italy) (2020)
    Elsevier
    Details
    Publication Date: 2023-10-26
    Description: In active volcanic zones, fault dynamics is considerably fast but it is often difficult to separate the pattern of nearly continuous large-scale volcanic processes (inflation/deflation processes, flank instability) from impulsive episodes such as dyke intrusions or coseismic fault displacements. At Etna, multidisciplinary studies on active faults whose activity does not strictly depend on volcanic processes, are relatively few. Here we present the case-study of the San Leonardello fault, an active structure located in the eastern flank of Mt. Etna characterised by a well-known seismic history. This fault saw renewed activity in May 2009, when pre-seismic creeping along the southern segment preceded an MW 4.0 earthquake in the northern segment, followed by some twenty-five aftershocks. Later, in March–April 2016, creep events reactivated the southern section of the same fault. Both the seismic and aseismic phenomena were recorded by the seismic and GNSS networks of INGV-Osservatorio Etneo, and produced surface faulting that left a footprint in the pattern of ground deformation detected by the InSAR measurements. We demonstrate that the integration of multidisciplinary data collected for volcano surveillance may shed light on different aspects of fault dynamics, and allow understanding how coseismic slip and creep alternate in space and time along the strike. Moreover, we use findings from our independent datasets to propose a conceptual model of the San Leonardello fault, taking into account behaviour and previous constraints from fault-based seismic hazard analyses. Although the faulting mechanisms described here occur at a very small scale compared with those of a purely tectonic setting, this case-study may represent a perfect natural lab for improving knowledge of seismogenic processes, also in other fault zones characterised by stick slip vs. stablesliding fault behaviour.
    Description: Published
    Description: 228554
    Description: 2T. Deformazione crostale attiva
    Description: JCR Journal
    Keywords: Fault ; Earthquake ; Creep ; Seismotectonics ; Behaviour ; Mt. Etna volcano ; 04.07. Tectonophysics ; 04.06. Seismology ; 04.03. Geodesy
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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