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  • 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring  (30)
  • 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous  (22)
  • Inversion
  • Seismological Society of America  (34)
  • Istituto Nazionale di Geofisica e Vulcanologia  (13)
  • 3
  • EGU
  • Wiley
Collection
Keywords
  • 1
    facet.materialart.
    Unknown
    Seismological Society of America
    Publication Date: 2018-03-12
    Description: The paper has not any abstract
    Description: Published
    Description: 720-727
    Description: 2T. Sorgente Sismica
    Description: 1IT. Reti di monitoraggio
    Description: JCR Journal
    Keywords: Earthquake ; Monitoring ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 2
    Publication Date: 2021-03-04
    Description: Macroseismic investigation with data collected through web- based questionnaires is today routinely applied by most impor- tant seismological institutions, such as the U.S. Geological Survey (http://earthquake.usgs.gov/earthquakes/dyfi/; last accessed December 2014), British Geological Survey (http://www. earthquakes.bgs.ac.uk/questionnaire/EqQuestIntro.html; last accessed December 2014), European-Mediterranean Seismological Centre (http://www.emsc-csem.org/Earthquake/Contribute/ choose_earthquake.php?lang=en; last accessed December 2014), Schweizerische Erdbebendienst (http://www.seismo.ethz. ch/eq/detected/eq_form/index_EN; last accessed December 2014), Bureau Central Sismologique Français (http://www .seisme.prd.fr/english.php; last accessed December 2014), and the New Zealand GeoNet project (http://www.geonet.org.nz/ quakes/; last accessed December 2014). The wide diffusion of Internet and the citizen collaboration (crowdsourcing) allow documentation of information on seismic effects and production of a macroseismic field with low costs and almost in real time. Transformation from qualitative information (as given by ques- tionnaires) to numerical quantification is a crucial issue. In the traditional evaluation of intensity, experts used to work through a complex comparison of effects basically driven by personal expe- rience. The major problem with this approach concerns the dif- ficulty in verifing and reproducing the evaluation process due to the lack of a detailed explanation of the employed workflow and to the large variability of possible cases. On the other hand, an automatic method for the estimation of macroseismic intensities needs to be completely well defined and specified in order to be reproducible and verifiable. For these reasons, this paper presents a comprehensive explanation of our intensity assessment method. A useful automatic method for intensity assessment should be computationally fast and strictly follow the macroseismic scales. To meet these requirements in 2010, we proposed a method that firstly quantified the effects using additive scores associated with each answer of the questionnaire item and then determined an intensity estimate for each questionnaire (Sbarra et al., 2010). After a trial period and having collected more than 500,000 questionnaires, we were able to thoroughly test the method. As a result of this testing, we describe here a new improved method that takes into account further factors, such as the situation and the location of the observer (Sbarra et al., 2012, 2014), to obtain a more accurate estimate of the macroseismic intensity degree at the municipality level. In this paper, we show some applications of our method with reference to the Mercalli–Cancani–Sieberg (MCS) scale, because this scale has long been used with Italian earthquakes and allows easy comparison between these intensities and other traditional ones.
    Description: Published
    Description: 985-990
    Description: 3T. Pericolosità sismica e contributo alla definizione del rischio
    Description: 5T. Sorveglianza sismica e operatività post-terremoto
    Description: 4IT. Banche dati
    Description: JCR Journal
    Description: reserved
    Keywords: Macroseismics ; intensity ; questionnaires ; attenuation ; 04. Solid Earth::04.06. Seismology::04.06.04. Ground motion ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring ; 05. General::05.01. Computational geophysics::05.01.05. Algorithms and implementation
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 3
    Publication Date: 2021-03-04
    Description: We investigate the influence of building height on the ability of people to feel earthquakes and observe that, in an urban area, short and tall buildings reach different levels of excitation. We quantify this behavior by analyzing macroseismic reports collected from individuals through the Internet, focusing on transitory effects, therefore in the elastic regime during recent earthquakes in Italy in the local magnitude (ML) range of 3 to 5.9. We find a maximum difference of 0.6 intensity units between the top floors of tall (7–10 stories) and short (1–2 stories) buildings at the highest considered magnitudes. As expected, tall buildings experience greater shaking than short buildings during large earthquakes at large source distances. However, we observe the opposite behavior at close distances when the ML is less than 3.5. These results can be explained by considering the different spectra radiated by small and large earthquakes and the different fundamental mode resonances of buildings (i.e., shorter buildings have higher resonance frequencies and vice versa). Using idealized building models excited by real acceleration time histories, we compute synthetic accelerograms on the top floors of short and tall buildings, and confirm the trend of the observed differences in felt intensities.
    Description: Published
    Description: 1803-1809
    Description: 3T. Pericolosità sismica e contributo alla definizione del rischio
    Description: JCR Journal
    Description: reserved
    Keywords: Macroseismics ; intensity ; building height ; 04. Solid Earth::04.06. Seismology::04.06.04. Ground motion ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 4
    Publication Date: 2017-04-04
    Description: Earthquake-rotated objects (EROs) have been observed and described for centuries (e.g., Hoffmann, 1838; Mallet, 1862; Reid, 1910). Several theories about the rotating mechanisms have been developed. Kozák (2006) classified rotating effects as those caused by a deviation between the projection of the center of gravity into the contact plane and the point of strongest adhesion (Rot1) and those due to subsequent arrival of ground-motion phases from different directions (Rot2). The EROs found in the literature include parts of buildings, such as chimneys, monuments, tombstones, and columns, often described with great care and in detail by early earthquake reports (Mallet, 1862) or still accessible (Boschi et al., 1995). However, in most cases rotational effects are observed on vertically oriented objects such as gravestones, tall monuments, and single columns (Kozák, 2009). Although earthquake- toppled objects (ETOs) allow the determination of minimum ground-motion thresholds which caused the toppling (Kamai and Hatzor 2008; Hinzen, 2010, 2012), EROs and earthquake-deformed objects (EDOs) present the chance to make a more detailed back calculation of the causative ground motion (Yegian et al., 1994; Lee et al., 2009; Hinzen et al., 2010; Hough et al., 2012). Numerous EROs were observed and documented during the 2009 L’Aquila earthquake in central Italy. Cucci and Tertulliani (2011) and Castellano et al. (2012) showed a correlation between the occurrence of EROs in the mesoseismal zone, the fault orientation, and the site conditions. Some of the simply structured and vertically oriented objects mapped by Cucci et al. (2011) and Cucci and Tertulliani (2011) offer the opportunity to use local strong-motion records to test different hypotheses about the mechanisms that caused the rotation. A main question in this context is whether near-field rotational components of ground motion are necessary to rotate the studied objects or whether 3D purely translational ground motions are sufficient to explain the observations. In this study, we use discrete-element models of EROs that are based on laser scans to study the dynamic behavior of the EROs and rotations induced by translation ground motions and uneven foundations.
    Description: Published
    Description: 745-751
    Description: 3T. Pericolosità sismica e contributo alla definizione del rischio
    Description: JCR Journal
    Description: restricted
    Keywords: earthquake rotations ; L'Aquila 2009 earthquake ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 5
    Publication Date: 2017-04-04
    Description: In the past few years, the awareness that earthquake-induced rotational effects can be significant in the near-fault region of an earthquake, and the consequent implications in seismic engineering, has gained rotational seismology a strong recovery in the attention of the scientific community. Impulses came from direct observations as well as numerical simulations, and special volumes related to this topic have been recently published by the Bulletin of the Seismological Society of America (Lee et al., 2009) and by the Journal of Seismology (Igel et al., 2012). In particular, some of the most recent papers on this subject addressed the earthquake-rotated objects (EROs hereinafter), considering the possible contribution to EROs occurrence from true rotational motion and/or translational motion (Kozák, 2006, 2009; Yang et al., 2010; Hinzen, 2012), the geometry of the structure (Mucciarelli et al., 2011), the clockwise/ counterclockwise (CW/CCW hereinafter) sense of rotation (Yegian et al., 1994), and the geological conditions at the site (Cucci and Tertulliani, 2011; Castellano et al., 2012). The renewed attention to earthquake-induced rotations allowed the collection of a significant dataset of EROs following the Mw 6.3 2009 L’Aquila (Central Italy) event (see Cucci et al., 2011 for a complete description of the dataset); this kind of data collection is a sound starting point for subsequent quantitative analyses of the data. In this paper, we present a newⒺdataset of EROs (available in the electronic supplement to this paper) originated by the Emilia seismic sequence, which occurred in northern Italy in 2012. The main aim of this study is to verify whether and how the distribution of the 2012 EROs is influenced by some geophysical observables (epicentral distance, intensity, directivity, lithology, etc.), in a geomorphological and seismological context completely different from that of 2009 L’Aquila.
    Description: Published
    Description: 973-981
    Description: 3T. Pericolosità sismica e contributo alla definizione del rischio
    Description: JCR Journal
    Description: restricted
    Keywords: earthquake rotations ; Emilia 2012 earthquakes ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 6
    Publication Date: 2020-02-24
    Description: Accurate earthquake locations are crucial for investigating seismogenic processes, as well as for applications like verifying compliance to the Comprehensive Test Ban Treaty. Earthquake location accuracy is related to the degree of knowledge about the 3-D structure of seismic wave velocity in the Earth. It is well known that modeling errors of calculated travel times may have the effect of shifting the computed epicenters far from the real locations by a distance even larger than the size of the statistical error ellipses, regardless of the accuracy in picking seismic phase arrivals. In the present study, we develop a method of seismic location based on a set of well located events recorded by the dense national seismic network in a seismically active region of central Japan. We show that mislocations of the order of 10-20 km affecting the epicenters calculated from a global seismic network and using the standard IASPEI91 travel times can be effectively removed by applying station-source-specific corrections. The results show a clear correlation of the travel time residuals with the subduction structure beneath Japan.
    Description: Published
    Description: 225-236
    Description: 2T. Tettonica attiva
    Description: JCR Journal
    Description: restricted
    Keywords: Travel-time correction ; Teleseimic location ; Seismic monitoring and test-ban treaty verification. ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 7
    Publication Date: 2017-04-04
    Description: Mt. Vesuvius (southern Italy) is one of the most hazardous volcanoes in the world. Its activity is currently characterized by moderate seismicity, with hypocenters located beneath the crater zone with depth rarely exceeding 5 km and magnitudes generally less than 3. The current configu- ration of the seismic monitoring network of Mt. Vesuvius consists of 18 seismic stations and 7 infrasound microphones. During the period 2006- 2010 a seismic array with 48 channels was also operative. The station distribution provides appropriate coverage of the area around the volcanic edifice. The current development of the network and its geometry, under conditions of low seismic noise, allows locating seismic events with M〈1. Remote instruments continuously transmit data to the main acquisition center in Naples. Data transmission is realized using different technological solutions based on UHF, Wi-Fi radio links, and TCP/IP client-server applications. Data are collected in the monitoring center of the Osservatorio Vesuviano (Italian National Institute of Geophysics and Volcanology, Naples section), which is equipped with systems for displaying and analyzing signals, using both real-time automatic and manual procedures. 24-hour surveillance allows to immediately communicate any significant anomaly to the Civil Protection authorities.
    Description: Published
    Description: S0450
    Description: 5V. Sorveglianza vulcanica ed emergenze
    Description: 1IT. Reti di monitoraggio e Osservazioni
    Description: JCR Journal
    Description: open
    Keywords: Vesuvius ; seismic network ; volcano monitoring ; network performance ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring ; 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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  • 8
    Publication Date: 2021-06-25
    Description: We adopt a spectral-element method (SEM) to perform numerical simulations of the complex wavefield generated by the 6 April 2009 Mw 6.3 L’Aquila earthquake in central Italy. The mainshock is represented by a finite-fault solution obtained by inverting strong-motion and Global Positioning System data, testing both 1D and 3D wavespeed models for central Italy. Surface topography, attenuation, and the Moho discontinuity are also accommodated. Including these complexities is essential to accurately simulate seismic-wave propagation. Three-component synthetic waveforms are compared to corresponding velocimeter and strong-motion recordings. The results show a favorable match between data and synthetics up to ∼0:5 Hz in a 200 km × 200 km × 60 km model volume, capturing features mainly related to topography or low-wavespeed basins. We construct synthetic peak ground velocity maps that, for the 3D model, are in good agreement with observations, thus providing valuable information for seismic-hazard assessment. Exploiting the SEM in combination with an adjoint method, we calculate finite-frequency kernels for specific seismic arrivals. These kernels capture the volumetric sensitivity associated with the selected waveform and highlight prominent effects of topography on seismic-wave propagation in central Italy.
    Description: Published
    Description: JCR Journal
    Description: restricted
    Keywords: Wave Propagation ; Earthquake ; Ground Motion ; Basin & Site Effects ; Topographic Effects ; Numerical Modelling ; Spectral-Element Methods ; Adjoint Methods ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 9
    Publication Date: 2017-04-04
    Description: In 2012 two seismic surveys were carried out in the area of Bagnolifutura (Campi Flegrei, Naples), with the aim of characterizing the properties of the seismic noise during the drilling activity performed in the framework of the Campi Flegrei Deep Drilling Project (CFDDP; https://sites.google.com/site/cfddpproject/). During the first survey, which was conducted from 2 to 4 April, before the drilling, seven broadband three-component seismometers were installed in two different array configurations. The second survey started on November 26, in concomitance with the drilling operations and fluid injection, and ended on December 5, four days after the end of the drilling, when the maximum depth of 502 m was reached. During this period seven broadband and one short-period three-component sensors were installed. A preliminary spectral analysis was performed on samples of seismic noise; moreover the root mean square of the amplitude of the signals and the polarization parameters were calculated. The preliminary results show similar spectral and polarization features for the data of the two surveys, whereas the amplitude of the seismic noise collected during the second survey is greatly influenced by the bad meteorological conditions. As future development experimental site transfer functions from Nakamura’s technique and surface wave dispersion from array techniques will be calculated to obtain the shallow crustal structure. The results corresponding to the different phases of the drilling activity will be compared, with the aim of establishing if significant variations of the medium properties have occurred during the experiment. Moreover the recorded signals will be deeply investigated in order to detect the eventual occurrence of microseismicity induced by fluid injection and to define its features.
    Description: Published
    Description: 1-18
    Description: N/A or not JCR
    Description: open
    Keywords: Campi Flegrei ; seismic noise ; array techniques ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 10
    Publication Date: 2017-04-04
    Description: In the present paper, we will describe the field survey (Fig. 1) and the data analysis of an experiment carried out to put constraints on the magnitude detection threshold in the area of Campi Flegrei. Results show that seismic radiation emitted from VT seismic events at frequency lower than 2 Hz has a high detection threshold (minimum magnitude around 1.5). In the range between 2 and 20 Hz, VT events with magnitudes smaller than about 0.5 have a high probability to be undetected. This result indicates that noise reduction through borehole stations and/or small arrays is essential for an accurate seismic monitoring in the Campi Flegrei area.
    Description: Published
    Description: 190-198
    Description: 3.1. Fisica dei terremoti
    Description: JCR Journal
    Description: restricted
    Keywords: seismic noise ; magnitude detection ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.06. Seismology::04.06.09. Waves and wave analysis
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 11
    Publication Date: 2017-04-04
    Description: On 20 May 2012, at 02:03:52 GMT, an earthquake with Mw 6.1 (RCMT, http://www.bo.ingv.it/RCMT) occurred in northern Italy striking a densely populated area. The mainshock was followed a few hours later by two severe aftershocks having the same local magnitude (Ml 5.1, 1 and 2 in Figure 1a), and by hundreds of smaller aftershocks. Nine days later, on 29 May, at 07:00:03 GMT, a second event with moment magnitude Mw 6.0 (RCMT, http://www.bo.ingv.it/RCMT) occurred to the west, on an adjacent fault segment. This event was also followed by hundreds of aftershocks, three of them having local magnitude 5.3, 5.2 and 5.1 (3, 4 and 5, respectively, in Figure 1a) (locations from Istituto Nazionale di Geofisica e Vulcanologia, hereinafter INGV, http://iside.rm.ingv.it/; Malagnini et al., 2012; Scognamiglio et al., 2012). Despite the moderate number of casualties if compared to other major events in the Italian history, the economic loss was extremely high, resulting in about EUR 5 billion (AON Benfield, 2012, http://www.aon.com/), as the majority of Italian industrial activities and infrastructures concentrate in this area, the eastern Po plain, which is the largest sedimentary basin in Italy. The mainshocks are associated to two thrust faults with an approximate E-W trend dipping to the South (Figure 1b). The majority of the faults in this region are located in the upper crust, at depths lower than 10 km. The two main shocks are among the strongest earthquakes generated by thrust faults ever recorded in Italy in the instrumental era. The Emilia sequence has been extensively recorded by several strong-motion networks, operating in the Italian territory and neighbouring countries. Some of the networks acquire continuous data streams at their national data centres, which are nodes of EIDA (European Integrated Data Archive, hhtp://eida.rm.ingv.it), a federation of several archives, so that the waveforms can be obtained immediately after the occurrence of an event. Other networks, such as the Italian accelerometric network (RAN), managed by the Italian Department of the Civil Protection (hereinafter DPC), distribute the acceleration waveforms through their web site (http://protezionecivile.gov.it). The data set explored in this study is relative to the six events of the sequence having Ml 〉 5 (Table 1) and consists in 365 accelerograms recorded within a distance of 200 km from the epicentres, that were provided by the permanent and temporary seismic networks of INGV, the Swiss Seismological Service (SED, http://www.seismo.ethz.ch/index) and the DPC.
    Description: Published
    Description: 629-644
    Description: 1.1. TTC - Monitoraggio sismico del territorio nazionale
    Description: JCR Journal
    Description: open
    Keywords: Strong motion ; May-June 2012 Emilia Romagna earthquake sequence ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous ; 04. Solid Earth::04.06. Seismology::04.06.04. Ground motion ; 04. Solid Earth::04.06. Seismology::04.06.09. Waves and wave analysis ; 04. Solid Earth::04.06. Seismology::04.06.11. Seismic risk
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 12
    Publication Date: 2017-04-04
    Description: In the 1980's, from an analysis of satellite images, Russian scientists reported on a short-term thermal infrared radiation enhancement that occurred before some medium-to-large earthquakes in central Asia [Gorny et al. 1988]. Since then, many researchers have been studying earthquake thermal anomalies with satellite remote sensing data [Qiang et al. 1991, Tronin 1996, Tramutoli et al. 2001, Ouzounov and Freund 2004, Saraf and Choudhury 2004, Aliano et al. 2008, Blackett et al. 2011]. Recently, abnormal surface latent heat flux [Dey and Singh 2003, Cervone et al. 2005, Qin et al. 2009, Qin et al. 2011, Qin et al. 2012], outgoing long-wave radiation [Ouzounov et al. 2007] and microwave radiation [Takashi and Tadashi 2010] have also been shown to precede earthquakes. To investigate the possible physical mechanisms of such satellite thermal anomalies, some studies conducted a series of detecting experiments on rock loaded to fracturing [Wu et al. 2000, Freund 2002, Wu et al. 2002, Wu et al. 2006a, Wu et al. 2006b, Freund et al. 2007], and some hypotheses have been proposed. These have included: leaking of pore-gas, and hence the resulting greenhouse effect [Qiang et al. 1995]; activating and recombining of p-holes during rock deformation [Freund 2002]; release of latent heat due to near-surface air ionization [Pulinets et al. 2006], and stress-induced thermal effects due to friction and fluids [Wu and Liu 2009]. According to the Istituto Nazionale di Geofisica e Vulcanologia (INGV; National Institute of Geophysics and Volcanology), two major earthquakes with almost the same large magnitudes struck northern Italy, on the Po Plain in the Emilia Region. The first hit on May 20, 2012, at 02:03 UTC, with ML 5.9 (44.89 °N, 11.23 °E; 6 km in depth), and the second on May 29, 2012, at 07:00 UTC, with ML 5.8 (44.85 °N, 11.09 °E; 10 km in depth). These caused a total of 27 deaths and widespread damage. In this study, the long-term temperature data from both satellite and ground (with greater emphasis on the satellite data) have been used to determine whether there were thermal anomalies associated with this Emilia 2012 seismic sequence. In particular, the next section will be dedicated to describing both the data and the method of analysis. In Section 3, we provide the more significant results, which we discuss in Section 4, together with the main conclusions. We acknowledge that this work cannot be exhaustive, as it will require more data and analyses. However, although further studies will be welcome, we are confident that we have done the best with the data at our disposal.
    Description: Published
    Description: 823-828
    Description: 1.10. TTC - Telerilevamento
    Description: 3.1. Fisica dei terremoti
    Description: JCR Journal
    Description: open
    Keywords: earthquake event ; numerical method ; surface temperature ; Emilia-Romagna, Italy ; Emilia ; 04. Solid Earth::04.02. Exploration geophysics::04.02.05. Downhole, radioactivity, remote sensing, and other methods ; 04. Solid Earth::04.06. Seismology::04.06.01. Earthquake faults: properties and evolution ; 04. Solid Earth::04.06. Seismology::04.06.03. Earthquake source and dynamics ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 13
    Publication Date: 2021-03-01
    Description: On September 6, 2002, at 01:21 GMT, the western part of the Tyrrhenian coast of Sicily was hit by an earthquake of magnitude ML = 5.6, representing the mainshock of a seismic sequence of roughly 500 earthquakes recorded in about one month. The event, although characterized by a moderate magnitude and located some forty kilometres offshore, produced relevant macroseismic effects in the Palermo area. A macroseismic survey was carried out soon after the earthquake with the aim of defining, for Civil Protection purposes, the damage scenario over a territory which is densely urbanised. In all, 134 localities were investigated. Damage generally depended on the high vulnerability of the buildings both for problems related to the old age - as is the case of the Palermo historical centre - and for peculiar unfavourable conditions due to site effects, particularly in some quarters of the city and in the nearby locality of Ficarazzi. Damage to masonry consisted of falling plaster, failure of corner walls, diagonal cracks in walls and widening of previous fissures. Some degraded buildings, almost abandoned and with evident lack of maintenance, suffered partial structural failure of roofs and floors. As regards reinforced concrete (RC) frame buildings, several edifices with 5-10 storeys suffered cracks in partitions and infill walls, sometimes with failure of these elements, and falling plaster. Fine cracks in beams of frames have also been observed, but without determining significant structural problems. In general, damage affects the lowest storeys of the RC frame buildings. According to the European Macroseismic Scale 1998, the maximum value of intensity, 6, was assigned to Palermo and Ficarazzi. The earthquake has also provoked effects on natural surroundings. Two types of phenomena have been detected: (i) hydrological effects and (ii) slope instability processes. The most relevant was the landslide which occurred near the village of Cerda, 60 km from the epicentre.
    Description: Published
    Description: 1-15
    Description: 1.11. TTC - Osservazioni e monitoraggio macrosismico del territorio nazionale
    Description: N/A or not JCR
    Description: open
    Keywords: Palermo ; terremoto 2002 ; macrosismica ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 14
    Publication Date: 2021-03-01
    Description: Il presente lavoro è costituito dalla raccolta sistematica delle indagini macrosismiche eseguite in occasione dei terremoti di maggior rilievo verificatisi in Sicilia orientale e Calabria meridionale dal Gennaio 1999 al Gennaio 2001. I rilievi precedenti al Settembre 1999 sono stati effettuati nell’ambito delle attività del Gruppo Nazionale per la Difesa dai Terremoti, svolte presso l’Istituto Internazionale di Vulcanologia – CNR di Catania. Successivamente a tale data le indagini macrosismiche hanno costituito parte integrante delle attività di monitoraggio del Sistema Poseidon. Entrambi gli enti adesso costituiscono la sezione di Catania dell’Istituto Nazionale di Geofisica e Vulcanologia.
    Description: Published
    Description: 1-59
    Description: 1.11. TTC - Osservazioni e monitoraggio macrosismico del territorio nazionale
    Description: N/A or not JCR
    Description: open
    Keywords: Sicilia ; terremoti ; macrosismica ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring
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  • 15
    Publication Date: 2017-04-04
    Description: After the 1976 Friuli earthquake (Ms = 6.5) in north-eastern Italy that caused about 1,000 casualties and widespread destruction in the Friuli area, the Italian government established the Centro di Ricerche Sismologiche (CRS). This is now a department of the Istituto Nazionale di Oceanografia e di Geofisica Sperimentale (OGS), and it is specifically devoted to the monitoring of the seismicity of north-eastern Italy. Since its inception, the North-East Italy Seismic Network has grown enormously. Currently, it consists of 14 broad-band and 20 short-period seismic stations, all of which are telemetered to and acquired in real time at the OGS-CRS data center in Udine. Data exchange agreements in place with other Italian, Slovenian, Austrian and Swiss seismological institutes lead to a total number of 94 seismic stations acquired in real time, which confirms that the OGS is the reference institute for seismic monitoring of north-eastern Italy. Since 2002, CRS has been using the Antelope software suite as the main tool for collecting, analyzing, archiving and exchanging seismic data. SeisComP is also used as a real-time data exchange server tool. A customized web accessible server is used to manually relocate earthquakes, and automatic procedures have been set-up for moment-tensor determination, shaking-map computation, web publishing of earthquake parametric data, waveform drumplots, state-of-health parameters, and quality checks of the station by spectra analysis. Scripts for email/SMS/fax alerting to public institutions have also been customized. Recently, a real-time seismology website was designed and set-up (http://rts.crs.inogs.it/).
    Description: Istituto Nazionale di Geofisica e Vulcanologia
    Description: Published
    Description: 67-75
    Description: 1.1. TTC - Monitoraggio sismico del territorio nazionale
    Description: JCR Journal
    Description: open
    Keywords: Seismological Research Center ; OGS ; acquiring seismic data ; archiving seismic data ; analyzing seismic data ; exchanging seismic data ; real time ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 16
    Publication Date: 2017-04-04
    Description: In this paper we investigate nature and properties of narrow-band, transient seismic signals observed by a temporary array deployed in the Val Tiberina area (central Apennines, Italy). These signals are characterized by spindle-shaped, harmonic waveforms with no clear S-wave arrivals. The first portion of the seismograms exhibits a main frequency peak centred at 4.5 Hz, while the spectrum of the slowly decaying coda is peaked at about 2 Hz. Events discrimination is performed using a matched-filtering technique, resulting in a set of 2466 detections spanning the 2010 January–March time interval. From a plane-wave-fitting procedure, we estimate the kinematic properties of signals pertaining to a cluster of similar events. The repetition of measurements over a large number of precisely aligned seismograms allows for obtaining a robust statistics of horizontal slownesses and propagation azimuths associated with the early portion of the waveforms. The P-wave arrival exhibits horizontal slownesses around 0.1 s km−1, thus suggesting waves impinging at the array almost vertically. Separately, we use traveltimes measured at a sparse network to derive independent constraints on epicentral location. Ray parameters and azimuths are calibrated using slowness measurements from a local, well-located earthquake. After this correction, the joint solution from traveltime inversion and array analysis indicates a source region spanning the 1–3 km depth interval. Considerations related to the source depth and energy, and the occurrence rate which is not related to the daily and weekly working cycles, play against a surface, artificial source. Instead, the close resemblance of these signals to those commonly observed in volcanic environments suggest a source mechanism related to the resonance of a fluid–filled fracture, likely associated with instabilities in the flux of pressurized CO2.
    Description: Published
    Description: 918-928
    Description: 1.1. TTC - Monitoraggio sismico del territorio nazionale
    Description: JCR Journal
    Description: reserved
    Keywords: Fracture and flow ; Earthquake source observations ; Interface waves ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 17
    Publication Date: 2017-04-04
    Description: Paper introducing and describing the EGU2010 SM1.3 session, "Seismic Centers Data Acquisition" (http://meetingorganizer.copernicus.org/EGU2010/session/2427)
    Description: Session «SM1.3 – Seismic Centers Data Acquisition» at the General Assembly 2010 of the European Geosciences Union (EGU), taking place in Vienna (Austria) between 2–7 May 2010, was organized to present both differences and similarities in operations by different types of seismic data centers in order to share experiences and stimulate constructive discussions. Only a few, widely used, "all-in-one" data acquisition and processing packages are available for seismic data centers, two public domain tools (SeisComP and EarthWorm) and one commercial tool (Antelope). The choice for any particular tool may depend on many different criteria, from operational aspects to scientific results, or on the availability of specific requirements in relation to a specific mission. The development of EarthWorm originally started in 1993 in the USA to replace aging and vendor tied regional processing systems. Antelope, on the other hand, started around 1996 with the aim to have real-time data flow from the field sensors to the scientist. SeisComP also started in the nineties as real-time data acquisition and processing system and evolved initially towards an early warning system for seismic observatories. Protocols have been established to exchange real-time waveform data between the different packages.
    Description: Istituto Nazionale di Geofisica e Vulcanologia
    Description: Published
    Description: 1-7
    Description: 1.1. TTC - Monitoraggio sismico del territorio nazionale
    Description: JCR Journal
    Description: open
    Keywords: EGU2010 ; Seismic Centers ; Data Acquisition ; Antelope ; SeisComP ; EarthWorm ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 18
    Publication Date: 2017-04-03
    Description: The seismic sequence that occurred in the Abruzzo Apennines near L’Aquila (Italy) in April 2009 caused extensive damage and a large number of casual- ties (more than 300). The earthquake struck an area in the Italian Apennines chain where several faults, belonging to adjacent seismotectonic domains, create a complex tectonic regime resulting from the interaction among regional stress buildup, local stress changes caused by individual earthquakes, and viscous-elastic stress relaxation. Understanding such complex interaction in the Apennines can lead to a large step for- ward in the seismic risk mitigation in Italy. The Abruzzo earthquake has been very well recorded by interferometric synthetic aperture radar (InSAR) data, much better than the first Italian earthquake ever recorded by satellites, namely, the 1997 Umbria–Marche earthquake. ENVISAT (ENVIronmental SATellite) data for the Abruzzo earthquake are, in fact, very clear and allow an accurate reconstruction of the faulting mechanism. We present here an accurate inversion of vertical deformation data obtained by ENVISAT images, aimed to give a detailed reconstruction of the fault geometry and slip distribu- tion. The resulting fault models are then used to compute, by a suitable theoretical model based on the elastic dislocation theory, the stress changes induced on the neigh- boring faults. The correlation of the subsequent mainshocks and aftershocks of the Abruzzo sequence with the volumes undergoing increasing Coulomb stress clearly evidence the triggering effect of coseismic stress changes on further seismicity. More- over, this analysis put in evidence which seismotectonic domains have been more heav- ily charged by stress released by the Abruzzo mainshocks. The most important faults significantly charged by the Abruzzo sequence belong to the Sulmona and Avezzano tectonic domains. Taking into account the average regional stress buildup in the area, the positive Coulomb stress changes caused by this earthquake can be seen as antici- pating the next earthquakes in the neighboring domains of 15–20 yr.
    Description: Published
    Description: 2340-2354
    Description: JCR Journal
    Description: restricted
    Keywords: Aquila Earthquakes of April 2009 ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 19
    Publication Date: 2017-04-04
    Description: A seguito dei tre eventi sismici di magnitudo ≥ 4.0, che tra il 10 e il 12 gennaio 2010 hanno colpito la zona del Fermano-Maceratese (Italia centrale), sono state installate due stazioni della rete sismica temporanea dell’INGV ad integrazione delle reti permanenti, nazionale e regionale, già presenti nell’area.
Questa zona ha una sismicità particolare confinata in uno strato sismogenetico fragile ad una profondità compresa tra 15 e 25 km meritevole di un’analisi dettagliata. Le stazioni sono state collegate in tempo reale al centro di acquisizione della Rete Sismica Nazionale dell’INGV utilizzando dei router UMTS. Questa soluzione si è rivelata estremamente rapida e conveniente. Solo una delle stazioni ha infatti risentito della debolezza del segnale UMTS, ma in generale i dati raccolti hanno contribuito a migliorare le localizzazioni ipocentrali prodotte in tempo reale presso la sala di sorveglianza sismica di Roma. L’integrazione dei dati acquisiti dalle stazioni temporanee ai dati prodotti dalle reti permanenti, ha fornito un dataset di buona qualità già rielaborato per degli studi di dettaglio dell’area.
    Description: Published
    Description: 1-30
    Description: 1.1. TTC - Monitoraggio sismico del territorio nazionale
    Description: N/A or not JCR
    Description: open
    Keywords: Emergency ; Seismic Monitoring ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring ; 04. Solid Earth::04.06. Seismology::04.06.10. Instruments and techniques
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 20
    Publication Date: 2017-04-04
    Description: Rapid evaluation of strong ground-shaking maps after moderate-to-large earthquakes is crucial to recognizing those areas where the largest damage and losses are expected. These maps play a fundamental role for emergency management. This is particularly important for areas having high seismic risk potential and covered by dense seismic networks. In near-real-time applications, ground-shaking maps are produced by integrating recorded data and estimates obtained by using ground-motion predictive equations, which assume point-source models. However, particularly for large earthquakes, improvements in the predictions of the peak ground motion can be obtained when fault extension and orientation are available. In fact, detailed source information allows one to use a more robust source-to-site distance metric compared with hypocentral distance. In this paper, a technique for estimating both fault extent (in terms of its surface projection) and dominant rupture direction is presented. This technique can be used in near-real-time ground-motion map calculation codes with the aim of improving ground-motion estimates with respect to a point-source model. The model parameters are estimated by maximizing a probability density function based on the residuals between observed and predicted peak-ground-motion quantities, the latter obtained by using predictive equations. The model space to be investigated is defined through a Bayesian approach, and it is explored by a grid-searching technique. The effectiveness of the proposed technique is demonstrated by offline numerical tests using data from three earthquakes occurring in different seismotectonic environments. The selected earthquakes are the 17 August 1999 Mw 7.5 Kocaeli (Turkey) earthquake, the 6 April 2009 Mw 6.3 L’Aquila (Italy) earthquake, and the 17 January 1994 Mw 6.7 Northridge (California) earthquake. The obtained results show that the proposed technique allows for fast and first order estimates of the fault extent and dominant rupture direction, which could be used to improve ground-shaking map calculations.
    Description: Published
    Description: 661-679
    Description: 4.1. Metodologie sismologiche per l'ingegneria sismica
    Description: JCR Journal
    Description: restricted
    Keywords: Source directivity ; ShakeMap ; L'Aquila earthquake ; Northridge earthquake ; Kocaeli earthquake ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 21
    Publication Date: 2017-04-04
    Description: L’area veneta delle Alpi orientali è caratterizzata da una debole sismicità di background. In particolare, l’attività sismica registrata negli ultimi 30 anni [Castello et al., 2006; Bollettino Sismico INGV1] mostra eventi di bassa energia (ML〈3) lungo l’arco alpino in corrispondenza dell’anticlinale del Montello (situato a NW di Treviso). Sono noti però alcuni eventi di magnitudo medio-alta che hanno storicamente interessato la regione: l’episodio più significativo è il terremoto di Asolo del 1695 (Imax 10 e MaW 6.61), affiancato da tre ulteriori eventi sismici di intensità Imax≥VIII (magnitudo equivalente 6.0) avvenuti nel 778, 1286 e 1836 [CPTI Working group 2004] (Figura 1). Il Montello è catalogato tra i segmenti sismogeneticamente attivi del fronte alpino [Valensise and Pantosti, 2001; Galadini et al., 2005; Poli et al., 2008], originato dall’uplift di una struttura di thrust S-vergente, con slip rate di deformazione stimato tra 1.5 mm/yr [Burrato et al., 2009] e 1.8-2.0 mm/yr [Benedetti et al., 2000]. Scopo del progetto OMBRA è quello di studiare alcune questioni ancora aperte e scientificamente controverse. Ci si chiede come questi eventi storici forti possano integrarsi nel contesto della debole sismicità di fondo osservata recentemente. Inoltre è interessante capire come una velocità di placca relativamente alta possa accomodarsi nel pattern regionale e inoltre quali strutture tra l’anticlinale e il fronte alpino possano essere potenzialmente attive.
    Description: Published
    Description: 65-67
    Description: 1.1. TTC - Monitoraggio sismico del territorio nazionale
    Description: N/A or not JCR
    Description: open
    Keywords: temporary network ; seismotectonics ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 22
    Publication Date: 2017-04-03
    Description: The 2009 Mw 6.3 L’Aquila earthquake produced an impressive number of rotational effects on vertically organized objects such as chimneys, pillars, capitals, and gravestones. We present a dataset of such effects that consists of 105 observations at 37 different sites and represents a compendium of earthquake-induced instances of rotational effects that is unprecedented in recent times. We find that the absolute majority of the reported effects were observed in the epicentral zone and that most of the observations are located where the Mercalli–Cancani–Sieberg intensity is between 7 and 8–9. The evident asymmetry in the distribution of the rotational effects resembles the southeastward directivity of the macroseismic effects and highlights a significant convergence between rotations and damage. Finally, we perform some qualitative analyses to recognize and evaluate which geological and seismological parameters can be significant contributors to local rotations. We find that surface geology and amplification of the seismic motion at each reported location strongly influence the occurrence and the nature of the earthquake-induced rotational effects. Conversely, the contribution of the pattern of slip distribution on the fault plane plays only a secondary role in enhancing the rotational motion at each site.
    Description: Published
    Description: 1109-1120
    Description: JCR Journal
    Description: restricted
    Keywords: L’Aquila earthquake ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 23
    Publication Date: 2017-04-04
    Description: In widely used -2 source models the characteristics of high frequency radiation are described as being flat for frequencies between the source corner frequency and an upper limiting frequency fmax. Deviations from this behavior are described in a parameter which is understood as a general measure of the changes the signal undergoes on its way from the source to the receiver. In this study, we calculated  in Southeastern Sicily by using microearthquakes belonging to three different seismic sequences occurring in the area in 1990, 1999-2001, and 2002. The selected events form four different clusters whose seismic sources are located within a 2 km radius. Although the source-to-station paths are approximately the same inside a given cluster, the values of  change considerably at the same recording site from one event to another, also in the case of events having the same magnitude. We parameterized  in terms of event (E), and path (P and Diff) contributions. The term P represents the contribution on total  of both the whole source-to- station path and the near-surface geology, while Diff models the possible spatial variation in the parameter measured with respect to a reference source-station direction. Results show that the source contribution is not negligible and that there is a positive correlation with source size exists. Moreover, the hypothesis of a laterally homogeneous crustal structure within the area in question is not appropriate and significant variation in attenuating properties of the medium may occur in a very small distance range (also in the order of a few tens of meters). Our analysis suggests that the origin of the above mentioned variability is located near the recording site. Synthetic spectra are also computed in order to verify the actual significance of the parameterization employed and its capacity to separate the source and the path contribution to . We describe our spectra as a product of a Brune-type source spectrum and an exponential shaping term accounting for propagation effects. The seismic moments range between 3.8 ×1011 and 5.2 ×1013 N·m, the source radii range between 176 and 669 m, while the stress drop varies from 0.01 to 0.67 MPa.
    Description: Published
    Description: 1796-1809
    Description: 3.1. Fisica dei terremoti
    Description: JCR Journal
    Description: open
    Keywords: High-frequency spectral decay in P-wave acceleration ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 24
    Publication Date: 2017-04-04
    Description: The recent Mw 6.3 destructive L’Aquila earthquake has further stimulated the improvement of the Italian operational earthquake forecasting capability at different time intervals. Here, we describe a medium-term (10-year) forecast model for Mw ≥5:5 earthquakes in Italy that aims at opening new possibilities for risk mitigation purposes. While a longer forecast yielded by the national seismic-hazard map is the primary component in establishing the building code, a medium-term earthquake forecast model may be useful to prioritize additional risk mitigation strategies such as the retrofitting of vulnerable structures. In particular, we have developed an earthquake occurrence model for a 10-year forecast that consists of a weighted average of time-independent and different types of available time-dependent models, based on seismotectonic zonations and regular grids. The inclusion of time-dependent models marks a difference with the earthquake occurrence model of the national seismic-hazard map, and it is motivated by the fact that, at the 10-year scale, the contribution of time-dependency in the earthquake occurrence process may play a major role. The models are assembled through a simple averaging scheme whereby each model is weighted through the results of a retrospective testing phase similar to the ones carried out in the framework of the Collaboratory for the Study of Earthquake Predictability. In this way, the most hazardous Italian areas in the next ten years will arise from a combination of distinct models that place more emphasis on different aspects of the earthquake occurrence process, such as earthquake clustering, historical seismic rate, and the presence of delayed faults capable of large events. Finally, we report new challenges and possible developments for future updating of the model.
    Description: Published
    Description: 1195-1213
    Description: 4.2. TTC - Modelli per la stima della pericolosità sismica a scala nazionale
    Description: JCR Journal
    Description: restricted
    Keywords: Earthquake occurrence ; time-dependent and independent earthquake occurrence models ; csep testing ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 25
    Publication Date: 2017-04-04
    Description: In this paper, we adopt three ground-motion simulation techniques (EXSIM, Motazedian and Atkinson, 2005, DSM, Pacor et al., 2005 and HIC, Gallovič and Brokešová, 2007), with the aim of investigating the different performances in near-fault strong-motion modeling and prediction from past and future events. The test case is the 1980, M 6.9, Irpinia earthquake, the strongest event recorded in Italy. First, we simulate the recorded strong-motion data and validate the model parameters by computing spectral acceleration and peak amplitudes residual distributions. The validated model is then used to investigate the influence of site effects and to compute synthetic ground motions around the fault. Afterward, we simulate the expected ground motions from scenario events on the Irpinia fault, varying the hypocenters, the rupture velocities and the slip distributions. We compare the median ground motions and related standard deviations from all scenario events with empirical ground motion prediction equations (GMPEs). The synthetic median values are included in the median ± one standard deviation of the considered GMPEs. Synthetic peak ground accelerations show median values smaller and with a faster decay with distance than the empirical ones. The synthetics total standard deviation is of the same order or smaller than the empirical one and it shows considerable differences from one simulation technique to another. We decomposed the total standard deviation into its between-scenario and within-scenario components. The larger contribution to the total sigma comes from the latter while the former is found to be smaller and in good agreement with empirical inter-event variability.
    Description: In press
    Description: 4.1. Metodologie sismologiche per l'ingegneria sismica
    Description: JCR Journal
    Description: restricted
    Keywords: Irpinia 1980 earthquake ; ground-motion simulation ; ground-motion variability ; scenario events ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous ; 04. Solid Earth::04.06. Seismology::04.06.03. Earthquake source and dynamics ; 04. Solid Earth::04.06. Seismology::04.06.04. Ground motion
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  • 26
    Publication Date: 2017-04-04
    Description: The Centro di Ricerche Sismologiche (CRS, Seismological Research Center) of the Istituto Nazionale di Oceanografia e di Geofisica Sperimentale (OGS, Italian National Institute for Oceanography and Experimental Geophysics) in Udine (Italy) after the strong earthquake of magnitude Mw=6.4 occurred in 1976 in the Italian Friuli-Venezia Giulia region, started to operate the North-eastern Italy (NI) Seismic Network: it currently consists of 12 very sensitive broad band and 21 simpler short period seismic stations, all telemetered to and acquired in real time at the OGS-CRS data center in Udine. Real time data exchange agreements in place with other Italian, Slovenian, Austrian and Swiss seismological institutes lead to a total number of 93 seismic stations acquired in real time, which makes the OGS the reference institute for seismic monitoring of North-eastern Italy. Since 2002 OGS-CRS is using the Antelope software suite on a SUN SPARC cluster as the main tool for collecting, analyzing, archiving and exchanging seismic data, initially in the framework of the EU Interreg IIIA project “Trans-national seismological networks in the South-Eastern Alps”. SeisComP is also used as a real time data exchange server tool. In order to improve the seismological monitoring of the North-eastern Italy area, at OGS-CRS we tuned existing programs and created ad hoc ones like: a customized web server named PickServer to manually relocate earthquakes, a script for automatic moment tensor determination, scripts for web publishing of earthquake parametric data, waveforms, state of health parameters and shaking maps, noise characterization by means of automatic spectra analysis, and last but not least scripts for email/SMS/fax alerting. A new OGS-CRS real time seismological website (http://rts.crs.inogs.it/) has also been operative since more than one year in the framework of the Italian DPC-INGV S3 Project: the website shows classic earthquake locations parametric data plus shakemap and moment tensor information; recently also daily PSD quality check of seismic stations plots have been added. At OGS-CRS we also spent a considerable amount of efforts in improving the long-period performances of broadband seismic stations, either by carrying out full re-installations and/or applying thermal insulations to the seismometers: the example of the new PRED broad band seismic station installation in the cave tunnel of Cave del Predil using a Quanterra Q330HR high resolution digitizer and a Sterckeisen STS-2 broadband seismometer will be illustrated. Efforts have been put also in strengthening the reliability of data links, exploring the use of redundant satellite/radio/GPRS links.
    Description: Published
    Description: Vienna (Austria)
    Description: 1.1. TTC - Monitoraggio sismico del territorio nazionale
    Description: open
    Keywords: seismic monitoring ; Northeastern Italy ; real time ; OGS ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: Abstract
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  • 27
    Publication Date: 2017-04-04
    Description: A properly organized seismic network is a valuable tool for monitoring seismic zones and assessing seismic hazards. In this paper we propose a new method (seismic network evaluation through simulation, SNES) to evaluate the performance of hypocenter location of a seismic network. The SNES method gives, as a function of magnitude, hypocentral depth, and confidence level, the spatial distribution of the number of active stations in the location procedure and their relative azimuthal gaps, along with confidence intervals in hypocentral parameters. The application of the SNES method also permits evaluation of the magnitude of completeness (MC), the background noise levels at the stations, and assessment of the appropriateness of the velocity model used in location routine. Italy sits on a tectonically active plate boundary at the convergence of the Eurasian and African lithospheric plates and has a high level of seismicity. In this paper, we apply the SNES method to the Italian National Seismic Network (Rete Sismica Nazionale Centralizzata dell’Istituto Nazionale di Geofisica e Vulcanologia, RSNC– INGV) which has monitored Italian seismicity since the early 1980s, following the destructive 1980 Irpinia earthquake. In recent years, the RSNC–INGV has grown significantly. In fact, in February 2010, it received signals from 305 seismic stations, 258 with wideband three-component sensors. We constructed SNES maps for magnitudes of 1.5, 2, 2.5, and 3, fixing the hypocentral depth at 10 km and the confidence level at 95%. Through the application of the SNES method, we show that the RSNC–INGV provides the best monitoring coverage in the Apennine Mountains with errors that for M 2, are less than 2 and 4 km for epicenter and hypocentral depth, respectively. At M 2.5 this seismic network is capable of constraining earthquake hypocenters to depths of about 150 km for most of the Italian Peninsula. This seismic network provides a threshold of completeness down to M 2 for almost the entire Italian territory.
    Description: Published
    Description: 1213-1232
    Description: 2.5. Laboratorio per lo sviluppo di sistemi di rilevamento sottomarini
    Description: JCR Journal
    Description: reserved
    Keywords: Italian National Seismic Network ; Magnitude of Completeness ; Location Performance ; Seismic Noise ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring
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  • 28
    Publication Date: 2017-04-03
    Description: After an earthquake, rapid, real-time assessment of hazards such as ground shaking and tsunami potential is important for early warning and emergency response. Tsunami potential depends on sea floor displacement, which is related to the length, L, width, W, mean slip, D, and depth, z, of earthquake rupture. Currently, the primary discriminant for tsunami potential is the centroid-moment tensor magnitude, MwCMT, representing the seismic potency LWD, and estimated through an indirect, inversion procedure. The obtained MwCMT and the implied LWD value vary with the depth of faulting, assumed earth model and other factors, and is only available 30 min or more after an earthquake. The use of more direct procedures for hazard assessment, when available, could avoid these problems and aid in effective early warning. Here we present a direct procedure for rapid assessment of earthquake tsunami potential using two, simple measures on P-wave seismograms – the dominant period on the velocity records, Td, and the likelihood that the high-frequency, apparent rupture-duration, T0, exceeds 50-55 sec. T0 can be related to the critical parameters L and z, while Td may be related to W, D or z. For a set of recent, large earthquakes, we show that the period-duration product TdT0 gives more information on tsunami impact and size than MwCMT and other currently used discriminants. All discriminants have difficulty in assessing the tsunami potential for oceanic strike-slip and back-arc or upper-plate, intraplate earthquake types. Our analysis and results suggest that tsunami potential is not directly related to the potency LWD from the “seismic” faulting model, as is assumed with the use of the MwCMT discriminant. Instead, knowledge of rupture length, L, and depth, z, alone can constrain well the tsunami potential of an earthquake, with explicit determination of fault width, W, and slip, D, being of secondary importance. With available real-time seismogram data, rapid calculation of the direct, period- duration discriminant can be completed within 6-10 min after an earthquake occurs and thus can aid in effective and reliable tsunami early warning.
    Description: In press
    Description: 1.1. TTC - Monitoraggio sismico del territorio nazionale
    Description: JCR Journal
    Description: open
    Keywords: Earthquake dynamics ; Earthquake source observations ; Seismic monitoring ; Body waves ; Early warning ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 29
    Publication Date: 2021-11-09
    Description: Il 24 maggio 2011, alle 12.40 UTC, la Rete Sismica Nazionale (RSN) dell’Istituto Nazionale di Geofisica e Vulcanologia (INGV) ha registrato un evento sismico di magnitudo (ML) 3.1 nel distretto sismico1 [Selvaggi et al., 1996] del Montefeltro (in provincia di Forlì-Cesena). Nelle successive due settimane sono stati localizzati dalla Sala di Sorveglianza Sismica della sede romana dell’INGV oltre 600 eventi di cui 13 di ML ≥ 3.0. Otto di questi eventi più energetici sono accaduti entro le prime 16 ore dalla prima scossa. L’evento di maggiore energia si è verificato la notte tra il 24 e il 25 maggio (ore 22.03 UTC del 24 maggio) con una magnitudo pari a ML 3.7 (Tabella 1). Considerando la peculiare evoluzione della sequenza nelle prime 24 ore dal primo evento, la prossimità dell'area epicentrale all’Alta Val Tiberina (AVT nel seguito) dove è attualmente in corso un esperimento sismico passivo [Progetto NOVAT2; Cattaneo et al., 2011; D’Alema et al., 2011] e l’apprensione che stava diffondendosi tra la popolazione, è stato ritenuto opportuno attivare le procedure di risposta ad una emergenza sismica e predisporre un intervento volto a migliorare la copertura strumentale dell'area. Il 25 maggio, in accordo con i colleghi INGV della Sezione di Pisa, dell’Osservatorio di Arezzo [Braun, 2006], della sede di Ancona e della Fondazione Prato Ricerche3, si è proceduto con l'istallazione di una rete sismica temporanea ad integrazione delle stazioni permanenti già presenti in zona. Nella giornata del 27 maggio, due delle stazioni temporanee sono state predisposte per la trasmissione in tempo reale alla Sala di Sorveglianza Sismica di Roma dei dati acquisiti, per migliorare la precisione delle localizzazioni prodotte. Nel contempo, sono stati curati dei comunicati informativi divulgati attraverso il sito web4 dell’Ente, parzialmente inclusi in questo lavoro, per dare una risposta alla popolazione interessata dalla sequenza e fortemente preoccupata dall’intensificarsi della sismicità. Il presente lavoro, la cui redazione è stata completata mentre la sequenza è ancora in corso, vuole essenzialmente descrivere le procedure che vengono attivate all’INGV in risposta ad una emergenza sismica e fornire uno strumento tecnico di supporto alla successiva elaborazione della base dati raccolta nel corso dell'esperimento. Viene quindi presentata una breve introduzione sulle conoscenze sismologiche dell’area interessata dalla sequenza, vengono descritti i comunicati emessi dall’INGV per informare i cittadini e viene descritto l’intervento della rete sismica temporanea, ovvero la tempistica dell'istallazione, la strumentazione utilizzata, e i siti occupati.
    Description: Published
    Description: 1-17
    Description: 1.1. TTC - Monitoraggio sismico del territorio nazionale
    Description: N/A or not JCR
    Description: open
    Keywords: Seismic Monitoring ; Emergency ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 30
    Publication Date: 2017-04-04
    Description: The analysis of the seismic attenuation is a prominent and problematic component of hazard assessment. Over the last decade it has become increasingly clear that the intrinsic uncertainty of the decay process must be expressed in probabilistic terms. This implies estimating the probability distribution of the intensity at a site Is as the combination of the distribution of the decay DI and of the distribution of the intensity I0 found for the area surrounding that site. We focus here on the estimation of the distribution of DI. Previous studies presented in the literature show that the intensity decay in Italian territory varies greatly from one region to another, and depends on many factors, some of them not easily measurable. Assuming that the decay shows a similar behavior in function of the epicenter-site distance when the same geophysical conditions and building vulnerability characterize different macroseismic fields, we have classified some macroseismic fields drawn from the Italian felt report database by applying a clustering algorithm. Earthquakes in the same class constitute the input of a two-step procedure for the Bayesian estimation of the probability distribution of I at any distance from the epicenter, conditioned on I0, where DI is considered an integer, random variable, following a binomial distribution. The scenario generated by a future earthquake is forecast either by the predictive distribution in each distance bin, or by a binomial distribution whose parameter is a continuous function of the distance. The estimated distributions have been applied to forecast the scenario actually produced by the Colfiorito earthquake on 1997/09/26; for both options the expected and observed intensities have been compared on the basis of some validation criteria. The same procedure has been repeated using the probability distribution of DI estimated on the basis of each class of macroseismic fields identified by the clustering algorithm.
    Description: Published
    Description: 2876-2892
    Description: 4.1. Metodologie sismologiche per l'ingegneria sismica
    Description: JCR Journal
    Description: open
    Keywords: Macroseismic fields ; Probability Distribution of the Intensity at Site ; Attenuation trends ; Colfiorito 1997 earthquake ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 31
    Publication Date: 2017-04-04
    Description: This study investigates the engineering applicability of two conceptually different finite-fault simulation techniques. We focus our attention on two important aspects: first to quantify the capability of the methods to reproduce the observed ground-motion parameters (peaks and integral quantities); second to quantify the dependence of the strong-motion parameters on the variability in the large-scale kinematic definition of the source (i.e., position of the nucleation point, value of the rupture velocity, and distribution of the final slip on the fault). We applied an approximated simulation technique, the deterministic-stochastic method and a broadband technique, the hybrid-integral-composite method, to model the 1984 Mw 5.7 Gubbio, central Italy, earthquake, at five accelerometric stations. We first optimize the position of the nucleation point and the value of the rupture velocity for three different final slip distributions on the fault by minimizing an error function in terms of acceleration response spectra in the frequency band from 1 to 9 Hz. We found that the best model is given by a rupture propagating at about 2:65 km=sec from a hypocenter located approximately at the center of the fault. In the second part of the article we calculate more than 2400 scenarios varying the kinematic source parameters. At the five sites we compute the residuals distributions for the various strongmotion parameters and show that their standard deviations depend on the source parameterization adopted by the two techniques. Furthermore, we show that Arias Intensity (AI) and significant duration are characterized by the largest and smallest standard deviation, respectively. Housner Intensity is better modeled and less affected by uncertainties in the source kinematic parameters than AI. The fact that the uncertainties in the kinematic model affects the variability of different ground-motion parameters in different ways has to be taken into account when performing hazard assessment and earthquake engineering studies for future events.
    Description: Published
    Description: 647-663
    Description: 4.1. Metodologie sismologiche per l'ingegneria sismica
    Description: JCR Journal
    Description: reserved
    Keywords: ground-motion simulation ; Gubbio 1984 ; ground-motion variability ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous ; 04. Solid Earth::04.06. Seismology::04.06.03. Earthquake source and dynamics ; 04. Solid Earth::04.06. Seismology::04.06.04. Ground motion
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 32
    Publication Date: 2017-04-04
    Description: In April 1998, a swarm of 1800 microearthquakes near the village of Iznajar (southern Spain) was recorded at the Granada basin short-period seismic network. Focal mechanisms from local P-wave polarities are poorly constrained and cannot characterize the seismotectonics of the series. Here we combine polarity information and multiplet relocation to address this issue. We use waveform cross correlation on P and S arrivals to identify events with highly similar seismograms, group our detections into multiplet clusters, and invert the cross-correlation time delays to obtain precise relative locations. Relative locations have errors of several tens to a few hundreds of meters horizontally and vertically, and define strike and dip of active fault patches with an accuracy of 20°–30°. We introduce the multiplet fault plane orientations into focal mechanism inversion, now yielding mostly well-constrained solutions, in addition to resolving the nodal plane symmetry. We observe mainly north-south left-lateral strike-slip faulting and a few north-northwest–south-southeast normal faulting solutions, illustrating the kinematic complexity of the swarm, and pointing to a local deformation style different from the nearby Granada basin.
    Description: Published
    Description: 3421-3429
    Description: 3.1. Fisica dei terremoti
    Description: JCR Journal
    Description: reserved
    Keywords: Fault plane solution ; Precise location ; Seismic swarm ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 33
    Publication Date: 2017-04-04
    Description: The Campi Flegrei caldera (southern Italy) is one of the most hazardous areas in the World as several hundred thousand people live there and where important socio-economic activities have developed. The caldera includes the western-most part of the city of Naples and extends into the Gulf of Pozzuoli (eastern Tyrrhenian basin; Fig. 1). The main feature of the present volcanic activity of the caldera is the episodic slow and high-amplitude soil movement (bradyseism) accompanied by intense and shallow seismic activity that only occurs during the uplift phase.
    Description: Published
    Description: 916-927
    Description: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Description: 1.8. Osservazioni di geofisica ambientale
    Description: JCR Journal
    Description: restricted
    Keywords: Campi Flegrei ; volcanic activity ; seafloor monitoring ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous ; 04. Solid Earth::04.06. Seismology::04.06.10. Instruments and techniques ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous ; 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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  • 34
    Publication Date: 2017-04-04
    Description: Horizontal-to-vertical spectral ratios using ambient noise (HVNSR) are commonly used in site effects studies. In the practice, many operators assume stability over time of HVNSR and base their analyses on few very short time windows. The availability of a long period of continuous microtremor recording allowed us to analyze three months of data coming from a dense array experiment performed at Cavola, a village in northern Apennines. This condition offers a good opportunity to check the validity of the stability assumption and to investigate variations of the local ambient noise wave-field composition. The Cavola site is characterized by landslide sediments over stiffer materials with a moderate impedance contrast and by a complex morphology. An intense industrial activity in the village contributes to the generation of seismic noise. After identifying this noise source in the time series, we evaluate its effects on HVNSR. The results indicate that the spectral peak of HVNSR varies in amplitude and frequency, posing a warning about stability in time. Analyzing the spectra we identify the anthropic activity as responsible for changes in the composition of the noise wave field. These variations affect HVNSR, including peak frequency and also ground-motion polarization.
    Description: Published
    Description: 1263-1275
    Description: 4.1. Metodologie sismologiche per l'ingegneria sismica
    Description: JCR Journal
    Description: restricted
    Keywords: noise measurements ; Rayleigh waves ; polarization ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring ; 04. Solid Earth::04.06. Seismology::04.06.09. Waves and wave analysis
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 35
    Publication Date: 2017-04-04
    Description: The Mw6.3 2009 L’Aquila earthquake produced an impressive number of rotational effects on vertically organized objects such as chimneys, pillars, capitals and gravestones. We present the dataset of such effects, that consists of 105 observations at 37 different sites and represents a compendium of earthquake-induced istances of rotational effects that is unprecedented in recent times. We find that the absolute majority of the reported effects was observed in the epicentral zone and that most of the observations are located where the MCS intensity is between 7 and 8-9. The evident asymmetry in the distribution of the rotational effects resembles the southeastward directivity of the macroseismic effects and highlights a significant convergence between rotations and damage. Finally, we perform some qualitative analyses to recognize and evaluate which *Manuscript Click here to download Manuscript: revised_text.doc 2 geological and seismological parameters can be significant contributors to local rotations. We find that surface geology and amplification of the seismic motion at each reported location strongly influence the occurrence and the nature of the earthquake-induced rotational effects. Conversely, the contribution of the pattern of slip distribution on the fault plane plays only a secondary role in enhancing the rotational motion at each site.
    Description: In press
    Description: 1.11. TTC - Osservazioni e monitoraggio macrosismico del territorio nazionale
    Description: JCR Journal
    Description: open
    Keywords: l'aquila earthquake ; rotationale effects ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 36
    Publication Date: 2017-04-04
    Description: In this work we give information on the characteristics of the Italian National Seismic Network and on the seismicity and main seismic sequences in Italy during 2008. During that year the Italian National Seismic Network localized 6969 events in Italy and neighboring areas, with an apparent minimum magnitude of completeness ML of 2.1. The entire Italian Seismic Bulletin 2008 was obtained using signals from 279 stations belonging to the INGV Italian National Seismic Network and to other local and regional networks, all with real-time connection to the Centro Nazionale Terremoti in Rome. Some evidences confirm the presence of a certain percentage of events due to anthropic activity (explosions), erroneously interpreted as earthquakes of lowmagnitude.We identify 14 areas with the presence of explosions due to surfacemining activity, generating events with ML not exceeding 2.2.
    Description: Published
    Description: 1-47
    Description: 5.2. TTC - Banche dati di sismologia strumentale
    Description: N/A or not JCR
    Description: open
    Keywords: Italian seismicity ; Quarry blasts ; Seismic sequences ; Italian Seismic Bulletin ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 37
    Publication Date: 2017-04-04
    Description: IEEE Standard for Local and Metropolitan Area Networks (hereafter IEEE 802.16; online at http://standards.ieee.org/getieee802/802.16.html) is one of the most promising mobile and fixed broadband wireless access technologies for next-generation all-IP networks in the 3.5 GHz band (European spectrum profile). Commonly known as Universal WiMAX (worldwide inter-operability for microwave access), this access technology reaches a high bit rate and covers large areas with a single base station, making it possible to offer connectivity to end users in a cost-effective way. A further useful property of the WiMAX technology is that the transmission can be used both in line-of-sight (LOS) and non-line-of-sight (NLOS) environments, allowing highly feasible communications (WiMAX Forum 2004). Thanks to these features, IEEE 802.16 opens the way to the use of wireless technologies in the environmental monitoring of areas such as seismic and volcanic zones.
    Description: European Community’s Sixth Framework Programme, Contract no. IST-034622-IP
    Description: Published
    Description: 411-419
    Description: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Description: JCR Journal
    Description: reserved
    Keywords: WiMAX ; volcano monitoring ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.06. Seismology::04.06.10. Instruments and techniques
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  • 38
    Publication Date: 2017-04-04
    Description: The existence of a relationship between regional seismicity and changes in volcanic activity has been the subject of several studies in the last years. Generally, activity in basaltic volcanoes such as Villarica (Chile) and Tungurahua (Ecuador) shows very little changes after the occurrence of regional earthquakes. In a few cases volcanic activity has changed before the occurrence of regional earthquakes, such as observed at Teide, Tenerife, in 2004 and 2005 (Tárraga et al., 2006). In this paper we explore the possible link between regional seismicity and changes in volcanic activity at Mt. Etna in 2006 and 2007. On 24 November, 2006 at 4:37:40 GMT an earthquake of magnitude 4.7 stroke the eastern coast of Sicily. The epicenter was localized 50 km SE of the south coast of the island, and at about 160 km from the summit craters of Mt. Etna. The SSEM (Spectral Seismic Energy Measurement) of the seismic signal at stations at 1 km and 6 km from the craters highlights that four hours before this earthquake the energy associated with volcanic tremor increased, reached a maximum, and finally became steady when the earthquake occurred. Conversely, neither before nor after the earthquake, the SSEM of stations located between 80 km and 120 km from the epicentre and outside the volcano edifice showed changes. On 5 September, 2007 at 21:24:13 GMT an earthquake of magnitude 3.2 and 7.9 km depth stroke the Lipari Island, at the north of Sicily. About 38 hours before the earthquake occurrence, there was an episode of lava fountain lasting 20 hours at Etna volcano. The SSEM of the seismic signal recorded during the lava fountain at a station located at 6 km from the craters highlights changes heralding this earthquake ten hours before its occurrence using the FFM method (e.g., Voight, 1988; Ortiz et al., 2003). A change in volcanic activity – with the onset of ash emission and Strombolian explosions – was observed a couple of hours before the occurrence of the regional earthquakes. It can be interpreted as the magmatic response to a change of the distribution of tectonic stress in the edifice before the earthquake. In the light of this hypothesis, we surmise that the magmatic system behaved similar to a dilatometer and promise news lines to forecasting the volcano activity.
    Description: EGU
    Description: Published
    Description: Vienna (Austria)
    Description: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Description: open
    Keywords: VOLCANIC ACTIVITY ; TREMOR ; EARTHQUAKE ; SSEM ; FAILURE FORECAST METHOD ; ETNA ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.06. Seismology::04.06.10. Instruments and techniques ; 05. General::05.01. Computational geophysics::05.01.01. Data processing ; 05. General::05.01. Computational geophysics::05.01.05. Algorithms and implementation
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: Abstract
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  • 39
    Publication Date: 2017-04-04
    Description: The monitoring of the seismic background signal – commonly referred to as volcanic tremor - has become a key tool for volcanic surveillance, particularly when field surveys are unsafe and/or visual observations are hampered by bad weather conditions. Indeed, it could be demonstrated that changes in the state of activity of the volcano show up in the volcanic tremor signature, such as amplitude and frequency content. Hence, the analysis of the characteristics of volcanic tremor leads us to pass from a mere monoparametric vision of the data to a multivariate one, which can be tackled with modern concepts of multivariate statistics. For this aim we present a recently developed software package which combines various concepts of unsupervised classification, in particular cluster analysis and Kohonen maps. Unsupervised classification is based on a suitable definition of similarity between patterns rather than on a-priori knowledge of their class membership. It aims at the identification of heterogeneities within a multivariate data set, thus permitting to focalize critical periods where significant changes in signal characteristics are encountered. The application of the software is demonstrated on sample sets derived from Mt. Etna during eruptions in 2001, 2006 and 2007-8.
    Description: EGU
    Description: Published
    Description: Vienna (Austria)
    Description: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: open
    Keywords: PATTERN CLASSIFICATION ; TREMOR ; KOHONEN MAP ; CLUSTER ANALYSIS ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 05. General::05.01. Computational geophysics::05.01.01. Data processing ; 05. General::05.01. Computational geophysics::05.01.02. Cellular automata, fuzzy logic, genetic alghoritms, neural networks ; 05. General::05.01. Computational geophysics::05.01.05. Algorithms and implementation
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: Abstract
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  • 40
    Publication Date: 2017-04-04
    Description: L’uso del rumore ambientale nella valutazione della risposta sismica locale sta diventando molto frequente data la sua facile applicabilità e sensibilità alla variazione spaziale della geologia superficiale. Ciò lo rende particolarmente adatto nelle aree urbane, dove la natura delle unità geologiche affioranti è mascherata dagli interventi antropici. Il lavoro descrive i metodi di acquisizione e di trattamento dei dati, utilizzati durante una campagna svoltasi nell'area urbana di Catania.
    Description: Published
    Description: 1-30
    Description: 1.8. Osservazioni di geofisica ambientale
    Description: N/A or not JCR
    Description: open
    Keywords: NOISE ; ACQUISIZIONE ; URBANA ; CATANIA ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring ; 04. Solid Earth::04.06. Seismology::04.06.10. Instruments and techniques ; 05. General::05.01. Computational geophysics::05.01.01. Data processing
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  • 41
    Publication Date: 2022-06-14
    Description: On 6 April 2009, at 01:32 GMT, an Mw 6.3 seismic event hit the central Apennines, severely damaging the town of L’Aquila and dozens of neighboring villages and resulting in approximately 300 casualties (Istituto Nazionale di Geofisica e Vulcanologia, http://www.ingv.it; MedNet, http://mednet.rm.ingv.it/proce- dure/events/QRCMT/090406_013322/qrcmt.html). This earth- quake was the strongest in central Italy since the devastating 1915 Fucino event (Mw 7.0). The INGV national seismic net- work located the hypocenter 5 km southwest of L’Aquila, 8–9 km deep. Based on this information and on the seismotectonic framework of the region, earthquake geologists traveled to the field to identify possible surface faulting (Emergeo Working Group 2009a, 2009b). The most convincing evidence of pri- mary surface rupture is along the Paganica fault, the geometry of which is consistent with seismological, synthetic aperture radar (SAR) and GPS data. Investigation of other known nor- mal faults of the area, i.e., the Mt. Pettino, Mt. San Franco, and Mt. Stabiata normal faults suggested that these structures were not activated during the April 6 shock (Emergeo Working Group 2009a, 2009b). In this report, we first describe the seismotectonic frame- work of the area, and then we present the field information that supports the occurrence of surficial displacement on the Paganica fault.
    Description: Published
    Description: 940-950
    Description: 3.2. Tettonica attiva
    Description: JCR Journal
    Description: open
    Keywords: Surface coseismic ruptures ; Paganica Fault ; earthquake ; 04. Solid Earth::04.04. Geology::04.04.01. Earthquake geology and paleoseismology ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.06. Seismology::04.06.01. Earthquake faults: properties and evolution ; 04. Solid Earth::04.06. Seismology::04.06.03. Earthquake source and dynamics ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 42
    Publication Date: 2017-04-04
    Description: This study investigates the engineering applicability of two conceptually different finite-fault simulation techniques. We focus our attention on two important aspects: first to quantify the capability of the methods to reproduce the observed ground-motion parameters (peaks and integral quantities); second to quantify the dependence of the strong-motion parameters on the variability in the large-scale kinematic definition of the source (i.e. position of nucleation point, value of the rupture velocity and distribution of the final slip on the fault). We applied an approximated simulation technique, the Deterministic-Stochastic Method DSM, and a broadband technique, the Hybrid-Integral-Composite method HIC, to model the 1984 Mw 5.7 Gubbio, central Italy, earthquake, at 5 accelerometric stations. We first optimize the position of nucleation point and the value of rupture velocity for three different final slip distributions on the fault by minimizing an error function in terms of acceleration response spectra in the frequency band from 1 to 9 Hz. We found that the best model is given by a rupture propagating at about 2.65 km/s from a hypocenter located approximately at the center of the fault. In the second part of the paper we calculate more than 2400 scenarios varying the kinematic source parameters. At the five sites we compute the residuals distributions for the various strong-motion parameters and show that their standard deviations depend on the source-parameterization adopted by the two techniques. Furthermore, we show that, Arias Intensity and significant duration are characterized by the largest and smallest standard deviation, respectively. Housner Intensity results better modeled and less affected by uncertainties in the source kinematic parameters than Arias Intensity. The fact that the uncertainties in the kinematic model affects the variability of different ground-motion parameters in different ways has to be taken into account when performing hazard assessment and earthquake engineering studies for future events.
    Description: In press
    Description: 4.1. Metodologie sismologiche per l'ingegneria sismica
    Description: JCR Journal
    Description: open
    Keywords: ground-motion simulation ; Gubbio 1984 ; ground-motion variability ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous ; 04. Solid Earth::04.06. Seismology::04.06.03. Earthquake source and dynamics ; 04. Solid Earth::04.06. Seismology::04.06.04. Ground motion
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 43
    Publication Date: 2017-04-04
    Description: In this note, we investigate the characteristics of ambient noise cross-correlations for station pairs in northern Italy, considering the secondary microseism bandwidth (0.1-0.6 Hz). The preliminary analysis that we performed exploiting the available continuous recording in the investigated area, agrees with the recent results of Pedersen et al. (2007): the directionality of the noise signal cannot be disregarded when the group velocity is estimated in the range 0.1-0.6 Hz and the selection of the path orientation for tomography must be carefully performed. In particular, while the favourable directions with respect to microseisms generated along the Atlantic coasts of France, Norway and British Islands cover a quite wide azimuthal range (from about 270N to 5N), allowing us to reliably estimate the fundamental mode Rayleigh group velocity for paths in the Alps (about 2.7 km/s), more care must be taken when the microseisms are generated in the Mediterranean Sea. In that case, different locations of the generating areas of microseisms could provide biased estimates of the group velocity due to differences between the true and the apparent velocity of propagation between the stations.
    Description: Published
    Description: 1389-1398
    Description: 1.1. TTC - Monitoraggio sismico del territorio nazionale
    Description: JCR Journal
    Description: reserved
    Keywords: microseisms ; ambient noise ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring
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  • 44
    Publication Date: 2017-04-04
    Description: The Campi Flegrei (southern Italy) is one of the most active calderas in the world. This caldera is characterized by episodes of slow vertical ground movement, called bradyseism. With several hundred thousand people living within its borders, this area is in a high-risk category should there be an eruption. The seismological monitoring system in the Campi Flegrei is based on nine seismic stations, eight of which are equipped with short-period seismometers (1 Hz), and one with a broadband seismometer (60 sec–50 Hz). While all of the seismic stations are located on land, part of the seismic activity occurs in the undersea area of the Pozzuoli Gulf (Campi Flegrei), where there are no seismic stations. This gap in the data coverage produces a biased and incomplete image of the volcanic area.We carried out an experiment in the Pozzuoli Gulf with the installation of two broadband seismic stations on the seafloor with remote and continuous data acquisition for a duration of 31 days between January and March 2005. Using the data acquired, we have computed the power spectral density (PSD) to characterize the background seismic noise, and to evaluate the true noise variation, we have generated the seismic noise probability density functions from the computed PSD curves. The results of our analysis show that the broadband seismic noise is high when compared with the Peterson noise model (land model), but for periods less than 0.3 sec, the seismic noise on the seafloor is lower than the recordings on land over the same period range. The last bradyseismic crisis (1982–1984) highlights the importance of this frequency range, where most of the spectral content of the recorded earthquakes was observed. Finally, we evaluate the detection threshold of a new seismic station located on the seafloor of the Campi Flegrei caldera considering the characteristics of the local seismicity. This analysis shows that the detection threshold for the sea-floor stations (Mw ∼ 0:2) is less than that for land stations (Mw ∼ 0:8).
    Description: Published
    Description: 2962–2974
    Description: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Description: JCR Journal
    Description: reserved
    Keywords: Campi Flegrei Caldera ; Sea-Floor and On-Land Seismic ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 45
    Publication Date: 2019-03-05
    Description: New duration-based local (ML) and moment (Mw) magnitude scales are obtained for the Campi Flegrei area through analysis of a dataset of local volcanotectonic earthquakes. First, the S-wave quality factor for the investigated area was experimentally calculated, and then the distance-correction curve, log A0(r), to be used in the Richter formula ML = log Amax − log A0(r), was numerically estimated by measuring the attenuation properties and, hence, propagating a synthetic S-wave packet in the earth medium. The local magnitude scale was normalized to fit the Richter formula that was valid for Southern California at a distance of 10 km. ML was estimated by synthesizing Wood–Anderson seismograms and measuring the maximum amplitude. For the same dataset, the moment magnitude was obtained from S-wave distance-corrected and site-corrected displacement spectra. Comparisons between local and moment magnitudes determined, along with the old duration magnitude (MD) routinely used at the Istituto Nazionale di Geofisica e Vulcanologia– Osservatorio Vesuviano, are presented and discussed. Moreover, the relationships between ML and Mw calculated for two reference sites are also derived.
    Description: Published
    Description: 1964-1974
    Description: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Description: JCR Journal
    Description: open
    Keywords: magnitude ; Campi Flegrei ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 46
    Publication Date: 2020-11-20
    Description: Il presente lavoro è costituito dalla raccolta sistematica delle indagini macrosismiche eseguite in occasione dei terremoti più energetici verificatisi in Sicilia orientale dal Gennaio 2002 al Dicembre 2005. Esso rappresenta l’estensione, agli anni più recenti, della compilazione effettuata per il periodo 1999-2001 [Azzaro et al., 2002], e più in generale è inserita nel contesto delle attività di pronto intervento macrosismico effettuate regolarmente in ambito regionale dal 1988. L’esecuzione di rilievi in occasione di eventi sismici significativi è una prassi ormai consolidata nelle attività di monitoraggio dell’INGV, che recentemente ha istituito a tal fine il gruppo di lavoro denominato QUEST (QUick Earthquake Survey Team, DP n° 44 del 25/02/2004). I dati raccolti assolvono ad una duplice funzione: 1) nell’immediatezza di un evento sismico, a definire il quadro degli effetti a supporto degli interventi di Protezione Civile e della Comunità Scientifica; 2) a risolvere lacune e problemi interpretativi dei terremoti del passato attraverso il confronto con gli effetti macrosismici degli eventi attuali. La raccolta sistematica di dati macrosismici anche nel caso di eventi di bassa magnitudo, che interessano estensioni areali limitate come quelle etnee, è comunque importante per l’implementazione di banche dati e cataloghi macrosismici sia a livello locale che nazionale. Nel primo caso è stato aggiornato il catalogo macrosismico dei terremoti etnei [Azzaro et al., 2000], recentemente reso disponibile anche su Internet. Nel secondo caso, la più recente versione del catalogo parametrico dei terremoti italiani [Gruppo di Lavoro CPTI, 2004] utilizzata per la redazione della nuova mappa di pericolosità sismica del territorio nazionale (Ordinanza PCM 3274 del 20/03/2003), incorpora i dati dei terremoti siciliani al di sopra della soglia del danno pubblicati in Azzaro et al. [2002, 2003]. I rilievi macrosismici di seguito riportati sono relativi a tutti i terremoti oltre la soglia del danno verificatisi nel periodo considerato, ovvero a quegli eventi che sono stati avvertiti in modo significativo dalla popolazione (Figura 1). In larga parte si tratta di eventi di area etnea che, soprattutto nel corso del 2002, hanno provocato effetti macrosismici di rilievo. Tra i terremoti regionali riportati, non è incluso il terremoto di Palermo del 2002 per il quale è disponibile uno studio specifico [Azzaro et al., 2003].
    Description: Published
    Description: 1-62
    Description: 1.11. TTC - Osservazioni e monitoraggio macrosismico del territorio nazionale
    Description: N/A or not JCR
    Description: open
    Keywords: NONE ; Sicilia ; terremoti ; macrosismica ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring ; 05. General::05.02. Data dissemination::05.02.02. Seismological data
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 47
    Publication Date: 2017-04-04
    Description: The spatial distribution of 414 earthquakes (1.0 ≤ ML ≤ 4.6), recorded from 1994 to 2002 in Southeastern Sicily (Italy), has been analyzed; it generally coincides with mapped Plio-Quaternary faults, including the NNW-SSE offshore fault system which is the most important tectonic structure of the area. For the best located events, we computed 70 focal mechanisms by combining P-wave polarities with S-wave polarizations. A predominance of strike-slip and normal faults was observed. Focal mechanisms were then inverted for stress tensor parameters using the algorithm of Gephart and Forsyth. The results highlighted a region governed mainly by a compressional stress regime. Moreover, anisotropy analysis of shear-waves showed a polarization of fast S-waves prevalently aligned in the NNW-SSE to NW-SE direction over the whole area. A finer analysis of stress tensor evidenced three regions characterized by slightly differing orientation of the greatest principal stress axis, 1. The eastern sector displays a nearly horizontal 1 trending NW-SE; the central sector is affected by a low dip NNW-SSE 1; whereas in the western sector a 1 NNW-SSE oriented, with a higher dip angle, was detected. Finally, the comparison of the spatial distribution of seismicity occurring during 1994-2002, with locations of previous instrumental earthquakes and larger (M ≥ 5.0) historical events showed that the seismic patterns are persistent.
    Description: Published
    Description: 1359–1374
    Description: JCR Journal
    Description: reserved
    Keywords: Stress direction ; focal mechanisms ; Shear-Wave Anisotropy ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 48
    Publication Date: 2017-04-04
    Description: In November 1999 and in January 2000, two microearthquake swarms occurred in Southeastern Sicily (Italy). They were analytically located in the depth range 17-25 km, some kilometers northward from the buried front of a regional foredeep, below the active thrust zone of the Sicily mountain chain. Their hypocentral distribution showed two distinct clusters, and comparison of the waveforms revealed clearly that the two swarms formed two distinct families of multiplet events. This led us: i) to carry out a precise relocation relative to two chosen master events of the families, and ii) to better define the geometrical structure of the two clusters. The cross-spectral method was applied to obtain precise readings of the wave onsets. SH-wave onsets were used instead of P-waves, as they showed clearer onsets and a good signal-to-noise ratio. Residuals of the relative locations showed small values, no more than several meters on average. The vertical extent of the two relocated clusters was 500 m and 250 m, respectively, while the horizontal extent was 250 m. Hypocenters of the first cluster clearly delineate a NNW trending plane with almost vertical dip, matching one nodal plane of the focal mechanism obtained as a composite solution of all events of the cluster. Given the considerable gap angles, because of unfavorable network geometry with respect to the events, the stability of our results was tested carrying out a Montecarlo experiment. Varying the onset times randomly in the range of 5 ms, a dispersion of the locations less than 10 m in longitude, and less than 50 m both in latitude and depth was found. Similar results were obtained when comparing relocations carried out with different master events. Thus, the overall geometrical characteristics of the clusters were not affected seriously by random errors. Considering the geo-structural framework of the region, together with the location and time evolution of the two clusters, fluids of plutonic origin are suggested as the trigger mechanism.
    Description: Published
    Description: 1479–1497
    Description: JCR Journal
    Description: reserved
    Keywords: earthquake swarms ; cross-correlation ; relative location ; master-event technique ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 49
    Publication Date: 2017-04-04
    Description: The new Italian National Seismic Network (INSN) is a dense network of broadband stations deployed for monitoring Italian seismicity. The network consists of 250 stations with a typical station spacing of !40 km. Earthquake early warning is the rapid detection of an event in progress, assessment of the hazard it poses, and transmission of a warning ahead of any significant ground motion. We explore the potential for using the INSN real-time network for the purpose of earthquake early warning. We run the ElarmS early warning methodology off-line using a data set of more than 200 events with magnitudes between 2.5 and 6.0. A scaling relation for magnitude determination from the dominant period of the first seconds of signal following the P onset is developed from the data set. The standard deviation in the magnitude estimates using this approach is 0.4 magnitude units, and all event magnitude estimates are within !0:75 magnitude units of the true magnitude. Given the existing distribution of seismic stations it takes an average of 10 sec after event initiation before the P wave has been detected at four stations. If we require a detection at four stations before issuing the first alert, then the blind zone, within which no warning would be available, has a radius of !37 km. The ElarmS methodology can provide a warning earlier than this but with a greater uncertainty. An assessment of past damaging earthquakes across Italy shows that applying ElarmS with the existing seismic network could provide warning to population centers in repeats of past events. For example, in a repeat of the 1980 Irpinia earthquake Naples could receive an !15- sec warning. The variations in the size of the blind zone and warning times for different regions can be used as a guide to selecting strategic locations for future station deployments.
    Description: Published
    Description: 495-503
    Description: 1.1. TTC - Monitoraggio sismico del territorio nazionale
    Description: JCR Journal
    Description: reserved
    Keywords: Early Warning ; Earthquake Location ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 50
    Publication Date: 2017-04-04
    Description: With the aim to find a more objective way to detect seismic families, we applied a series of successive steps to constrain the results of a waveform similarity analysis. The evaluation of similarity was carried out on the waveforms recorded in the period 1999–2003 by the stations operating in the Garfagnana area, located in northern Tuscany (Italy). The algorithm is based on the cross-correlation technique applied in a process that overcomes the limit of one order of magnitude between events to be compared through a bridging technique. In practice, if two couples of events (A, B) and (B, C), each exceeding the correlation threshold, share a common quake (B), then all three events are attributed to the same family even if the match between A and C is below a value chosen as a reference for similarity. To avoid any subjective choice of threshold for cross-correlation values, the results from the computation algorithm are submitted to a routine that gives increasing reliability to them if they are confirmed by the three components of the seismogram and if the number of families detected by each station is confirmed by more recordings. This latter constraint is made possible by the geometry of the recording network, with interdistances between stations of the order of 40–50 km. The process finally leads to the recognition of 27 families detected and confirmed by, on average, 3 stations that represent 40% of the recording capabilities. Since the performances of the recording network have been very odd in the past, especially in the early years of operation, the reliability of the detection is much higher, as in most cases the stations that detected the families were the only ones to be effectively recording. The methodology proved to be more efficient than other methods applied in the past; moreover, the results could be probably improved even more if, instead of doing a one-run process, it would be borne as a trial-and-error approach.
    Description: Published
    Description: 1903-1915
    Description: JCR Journal
    Description: reserved
    Keywords: Seismicity ; multiplets ; seismic families ; seismic sequences ; 04. Solid Earth::04.06. Seismology::04.06.03. Earthquake source and dynamics ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring ; 04. Solid Earth::04.06. Seismology::04.06.09. Waves and wave analysis
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 51
    Publication Date: 2017-04-04
    Description: A long sequence of moderate-magnitude earthquakes (5 M 6) struck central Italy in September and October 1997. At the end of the sequence a year later, the seismogenic area extends for about 60 km along the Apennines. The analysis of historical seismicity suggests that this seismic sequence filled a 700-year gap in this portion of the chain. Other historical sequences in the same area are characterized by prolonged seismic release on adjacent fault segments, probably due to the involvement of shallow and complex structures inherited by the compressive tectonics. The distribution of seismicity and the fault-plane solutions show that the extension in this region is accomplished by normal faults dipping at relatively low angles ( 40 ) to the southwest. The focal mechanisms of the largest shocks reveal normal faulting with extension perpendicular to the Apenninic chain (northeast–southwest), consistently with the Quaternary tectonics of the internal sector of the northern Apennine belt and with previous earthquakes in adjacent regions. Three mainshocks occurred on distinct 5- to 10-km-long fault segments, adjacent and slightly offset between each other. High-quality aftershock locations show that seismicity is confined within the sedimentary Mesozoic cover in the upper 8 km of the crust and that most of the aftershocks are shallower than the largest shocks, which nucleated at 6-km depth. Faults evidenced by aftershock locations have a planar geometry and show increased complexity toward the surface. Most of the aftershock focal mechanisms are dominated by normal faulting. Several strike-slip events occurred at shallow depths, reactivating portions of pre-existing thrust planes that segment the normal fault system. The spatiotemporal evolution of seismicity shows a peculiar migration of hypocenters along the strike of the main faults with multiple ruptures and the activation of fault segments before the occurrence of the main rupture episodes.
    Description: Published
    Description: 99-116
    Description: reserved
    Keywords: Seismic ; Sequence ; Central Italy ; Apennines ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 52
    Publication Date: 2017-04-04
    Description: A small aperture quadripartite seismic array was installed on the south-east flanks of Mt. Vesuvius about 1 km far from the crater axis, in order to improve the seismic monitoring of this active volcano. The array has the following main purposes: i) to discriminate natural-source generated signals by artificial-source-generated signals; ii) to detect and track the source of possible Long Period (LP) events; iii) to detect coherent phases in the low frequency noise that may be related to magma movements (tremor insurgence). In addition, the array greatly helps in locating the seismic signals produced by blasts (both in land and sea), allowing a fast discrimination of possible natural long period (LP) quakes. The array is also an useful tool for retrieving the kinematic properties of the wavefield associated to volcano-tectonic (VT) earthquakes (more than 99% of the whole natural seismicity) and to all the other transients which are routinely observed(landslides, artificial blasts). We also use the array to investigate if correlated signals are present in the background noise (insurgence of volcanic tremor). The main result obtained during this first year of observation is that one LP was clearly recognized in the background seismicity at Mt. Vesuvius.
    Description: Published
    Description: 344-355
    Description: open
    Keywords: Volcano monitoring ; Array techniques ; 04. Solid Earth::04.06. Seismology::04.06.06. Surveys, measurements, and monitoring
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  • 53
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    3
    In:  Computers and Geosciences, Münster, 3, vol. 28, no. 45, pp. 309-326, pp. L11609, (ISBN 0-471-26610-8)
    Publication Date: 2002
    Keywords: Inversion ; Data analysis / ~ processing ; Non-linear effects ; Discrimination ; C&G
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  • 54
    facet.materialart.
    Unknown
    Wiley
    In:  Mathematical Methods for Digital Computers, Volume 1, Sapporo, Japan, Wiley, vol. 17, no. 16, pp. 211-236, (ISBN 0080419208)
    Publication Date: 1967
    Keywords: Inversion
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  • 55
    facet.materialart.
    Unknown
    Wiley
    In:  Mathematische Methoden für Digitalrechner, Sapporo, Japan, Wiley, vol. 1, no. 16, pp. 106-126, (ISBN 0080419208)
    Publication Date: 1967
    Keywords: Inversion
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