http://hdl.handle.net/2122/238 2013-05-25T14:11:57Z http://hdl.handle.net/2122/8709 Title: Noise measurements at seismic array in the drilling site of Bagnolifutura, Campi Flegrei Authors: Petrosino, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Bianco, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Bobbio, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Castellano, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Cusano, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Del Pezzo, E.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Galluzzo, D.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; La Rocca, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Maiello, V.; Università degli Studi di Napoli Parthenope Abstract: 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. 2013-04-30T22:00:00Z http://hdl.handle.net/2122/8707 Title: A laser scanning-based method for fast estimation of seismic-induced building deformations Authors: Pesci, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia; Teza, G.; Dipartimento di Geoscienze, Università di Padova; Bonali, E.; DAPT, Università di Bologna; Casula, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia; Boschi, E.; Dipartimento di Fisica, Università di Bologna Abstract: Monitoring damaged buildings in an area where an earthquake has occurred requires the use of techniques which provide rapid and safe measurements even in emergency conditions. In particular, remote sensing techniques like terrestrial laser scanning (TLS) can satisfy these requirements, since they produce very dense point clouds in little time and also allow an accurate geometric modeling of observed buildings. Nevertheless, strong constraints on TLS data acquisition geometry, such as acquisition distance and incidence angles, typically characterize an area in seismic emergency conditions. In order to correctly interpret the data, it is necessary to estimate errors affecting TLS measurements in these critical conditions. A reliable estimation can be achieved by means of experiments and numerical simulations aimed at quantifying a realistic noise level, with emphasis on reduction of artifacts due to data acquisition, registration and modeling. This paper proposes a data analysis strategy in which TLS-based morphological maps computed as point-to-primitive differences are created. The method can be easily used for accurate surveying in emergency conditions. In order to demonstrate the proposed method in very diverse situations, it was applied to rapidly detect deformation traces in the San Giacomo Roncole Campanile (Modena), the Asinelli tower (Bologna) and the Cantalovo Church (Verona), three buildings damaged by the Mw 5.9 Emilia Romagna 2012 earthquake (Italy). 2013 International Society for Photogrammetry and Remote Sensing, Inc. (ISPRS) Published by Elsevier 2013-02-27T23:00:00Z http://hdl.handle.net/2122/8704 Title: Seismic risk perception test Authors: Crescimbene, Massimo; Istituto Nazionale di Geofisica e Vulcanologia, Sezione AC, Roma, Italia; La Longa, Federica; Istituto Nazionale di Geofisica e Vulcanologia, Sezione AC, Roma, Italia; Camassi, Romano; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia; Pino, Nicola Alessandro; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia Abstract: The perception of risks involves the process of collecting, selecting and interpreting signals about uncertain impacts of events, activities or technologies. In the natural sciences the term risk seems to be clearly defined, it means the probability distribution of adverse effects, but the everyday use of risk has different connotations (Renn, 2008). The two terms, hazards and risks, are often used interchangeably by the public. Knowledge, experience, values, attitudes and feelings all influence the thinking and judgement of people about the seriousness and acceptability of risks. Within the social sciences however the terminology of ‘risk perception’ has become the conventional standard (Slovic, 1987). The mental models and other psychological mechanisms which people use to judge risks (such as cognitive heuristics and risk images) are internalized through social and cultural learning and constantly moderated (reinforced, modified, amplified or attenuated) by media reports, peer influences and other communication processes (Morgan et al., 2001). Yet, a theory of risk perception that offers an integrative, as well as empirically valid, approach to understanding and explaining risk perception is still missing”. To understand the perception of risk is necessary to consider several areas: social, psychological, cultural, and their interactions. Among the various research in an international context on the perception of natural hazards, it seemed promising the approach with the method of semantic differential (Osgood, C.E., Suci, G., & Tannenbaum, P. 1957, The measurement of meaning. Urbana, IL: University of Illinois Press). The test on seismic risk perception has been constructed by the method of the semantic differential. To compare opposite adjectives or terms has been used a Likert’s scale to seven point. The test consists of an informative part and six sections respectively dedicated to: hazard; vulnerability (home and workplace); exposed value (with reference to population and territory); seismic risk in general; risk information and their sources; comparison between seismic risk and other natural hazards. Informative data include: Region, Province, Municipality of residence, Data compilation, Age, Sex, Place of Birth, Nationality, Marital status, Children, Level of education, Employment. The test allows to obtain the perception score for each factor: Hazard, Exposed value, Vulnerability. These scores can be put in relation with the scientific data relating to hazard, vulnerability and the exposed value. On January 2013 started a Survey in the Po Valley and Southern Apennines. The survey will be conducted via web using institutional sites of regions, provinces, municipalities, online newspapers to local spreading, etc. Preliminary data will be discussed. Improve our understanding of the perception of seismic risk would allow us to inform more effectively and to built better educational projects to mitigate risk. 2013-04-08T22:00:00Z http://hdl.handle.net/2122/8695 Title: The Campi Flegrei Blind Test: Evaluating the Imaging Capability of Local Earthquake Tomography in a Volcanic Area Authors: Priolo, E.; Dipartimento Centro di Ricerche Sismologiche (CRS), Istituto Nazionale di Geofisica e di Oceanografia Sperimentale (OGS); Lovisa, L.; Dipartimento Centro di Ricerche Sismologiche (CRS), Istituto Nazionale di Geofisica e di Oceanografia Sperimentale (OGS); Zollo, A.; Dipartimento di Scienze Fisiche, Universit`a degli Studi di Napoli “Federico II”,Napoli, Italy; B¨ohm, G.; Dipartimento di Geofisica della Litosfera (GDL), Istituto Nazionale di Geofisica e di Oceanografia Sperimentale (OGS), Trieste, Italy; D’Auria, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Gautier, S.; G´eosciences Montpellier, UMR 5243 CNRS, University Montpellier 2, Montpellier, France; Gentile, F.; Dipartimento Centro di Ricerche Sismologiche (CRS), Istituto Nazionale di Geofisica e di Oceanografia Sperimentale (OGS); Klin, P.; Dipartimento Centro di Ricerche Sismologiche (CRS), Istituto Nazionale di Geofisica e di Oceanografia Sperimentale (OGS); Latorre, D.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Michelini, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Vanorio, T.; Stanford Rock Physics Laboratory, Stanford University, Stanford, CA, USA; Virieux, J.; Institut des Sciences de la Terre (ISTerre), The Universit´e Joseph Fourier, Grenoble, France Abstract: During the 1982–1984 bradyseismic crises in the Campi Flegrei area (Italy), the University of Wisconsin deployed a network of seismological stations to record local earthquakes. In order to analyse the potential of the recorded data in terms of tomographic imaging, a blind test was recently set up and carried out in the framework of a research project. A model representing a hypothetical 3D structure of the area containing the Campi Flegrei caldera was also set up, and a synthetic dataset of time arrivals was in turn computed. The synthetic dataset consists of several thousand P- and S-time arrivals, computed at about fourteen stations. The tomographic inversion was performed by four independent teams using different methods. The teams had no knowledge of either the input velocity model or the earthquake hypocenters used to create the synthetic dataset. The results obtained by the different groups were compared and analysed in light of the true model. This work provides a thorough analysis of the earthquake tomography potential of the dataset recording the seismic activity at Campi Flegrei in the 1982–1984 period. It shows that all the tested earthquake tomography methods provide reliable low-resolution images of the background velocity field of the Campi Flegrei area, but with some differences. However, none of them succeeds in detecting the hypothetical structure details (i.e. with a size smaller than about 1.5–2 km), such as a magmatic chamber 4 km deep and especially the smaller, isolated bodies, which represent possible magmatic chimneys and intrusions. 2011-12-31T23:00:00Z http://hdl.handle.net/2122/8690 Title: RELATIVE LOCATION OF HYBRID EVENTS AT STROMBOLI VOLCANO, ITALY Authors: Longobardi, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; D'Auria, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Esposito, A. M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia Abstract: In this work we analyzed distinctive seismic events known as hybrid events. They were observed at Stromboli Volcano, during the 2007 eruption. Hybrid events have intermediate characteristics between volcano-tectonic and long-period events (Martini et alii 2007). Three main swarms of hybrid events occurred during March 2007 on days 6-8, 20 and 22. The total number of hybrid events observed during this period was about 3,500. Different procedures were used for the analysis: first the clustering of waveforms, then the absolute and relative location of these events. The waveform clustering (using Self-Organizing Map neural networks) has shown that most of the events belong to three main families. These clusters have persisted for a long time interval (more than 20 days). This suggests that the source has not undergone significant changes over this period. During the three most intense swarms we recorded also other waveforms belonging to different families. For each family we performed waveform stacking to improve the signal/noise ratio. Then, using a manual procedure, we obtained a preliminary absolute location for each family. Relative waveform shift for each family have been computed using the cross-spectrum method. These data have been used to perform a relative hypocenter location of each family using a double-difference approach. We observe that almost all the hypocenters fall at very shallow depth. This observation suggests that their source is linked to processes occurring very close to the volcano surface. In the period from March 6 to 8 the formation of a macroscopic fracture system was observed at the summit of the volcano. We infer a causal link between these structures and the source of the hybrid events located in the same position. 2011-12-31T23:00:00Z http://hdl.handle.net/2122/8688 Title: A unified 3D velocity model for the Neapolitan volcanic areas Authors: D'Auria, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Martini, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Esposito, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Ricciolino, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Giudicepietro, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia Editors: Marzocchi, W.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia; Zollo, A.; Università di Napoli Federico II Abstract: One of the main issues in seismic monitoring of active volcanic areas is the accurate location of earthquake hypocenters. Volcano-tectonic seismicity is often characterized by small magnitude swarms, recorded by few seismic stations with a high picking uncertainty. Sometimes events lacks clear S-wave arrivals, due to the nature of some volcanic sources. All these features, together with the complex crustal structure of volcanoes, makes the earthquake location problem critical in such areas. One of the most important effort for improving the quality of hypocenter location is the use of realistic 3D velocity models. In the last 10 years, several scientific papers proposed 2D and 3D velocity models for Mt. Vesuvius, Campi Flegrei and the Gulf of Naples. They comes from both active seismic data (VESUVIO 94, TOMOVES 96, MAREVES 97 and SERAPIS 2001 experiments) and from local earthquake tomography. In this report we propose a global unified velocity model spanning from Ischia island to Appennine Mts. that allows us to locate earthquakes in the Neapolitan volcanic areas and in the Gulf of Naples. This model comes from a weighted averaging of 5 tomographic velocity models and a background regional model. Most of the model provides only P-wave velocities, only 2 models, obtained through local earthquake tomography at Mt. Vesuvius and Campi Flegrei also gives a S-wave velocity estimate. We show the difference between this new model and the previous 1D models adopted for routine locations at INGV-Osservatorio Vesuviano. We also relocate some events, using non-linear techniques showing differences in hypocenter position from previous locations and the improvement in final traveltime residuals and location uncertainties. 2007-12-31T23:00:00Z http://hdl.handle.net/2122/8686 Title: New insights from seismic tomography on the complex geodynamic evolution of two adjacent domains: Gulf of Cadiz and Alboran Sea Authors: Monna, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Cimini, G. B.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Montuori, C.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Matias, L.; Centro de Geofísica, Universidade de Lisboa, Lisbon, Portugal.; Geissler, W. H.; Alfred-Wegener-Institut für Polar- und Meeresforschung, Bremerhaven, Germany.; Favali, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia Abstract: In this study, we present a three-dimensional P wave upper-mantle tomography model of the southwest Iberian margin and Alboran Sea based on teleseismic arrival times recorded by Iberian and Moroccan land stations and by a seafloor network deployed for 1 year in the Gulf of Cadiz area during the European Commission Integrated observations from NEAR shore sourcES of Tsunamis: towards an early warning system (EC NEAREST) project. The three-dimensional model was computed down to 600 kmdepth. The tomographic images exhibit significant velocity contrasts, as large as 3%, confirming the complex evolution of this plate boundary region. Prominent high-velocity anomalies are found beneath Betics-Alboran Sea, off-shore southwest Portugal, and north Portugal, at sublithospheric depths. The transition zones between high- and low-velocity anomalies in southwest and south Iberia are associated to the contact of oceanic and continental lithosphere. The fast structure below the Alboran Sea-Granada area depicts an L-shaped body steeply dipping from the uppermost mantle to the transition zone where it becomes less curved. This anomaly is consistent with the results of previous tomographic investigations and recent geophysical data such as stress distribution, GPS measurements of plate motion, and anisotropy patterns. In the Atlantic domain, under the Horseshoe Abyssal Plain, the main feature is a high-velocity zone found at uppermost mantle depths. This feature appears laterally separated from the positive anomaly recovered in the Alboran domain by the interposition of low-velocity zones which characterize the lithosphere beneath the southwest Iberian peninsula margin, suggesting that there is no continuity between the high-velocity anomalies of the two domains west and east of the Gibraltar Strait. 2012-12-31T23:00:00Z http://hdl.handle.net/2122/8682 Title: Magnitude scale for LP events: a quantification scheme for volcanic quakes Authors: Del Pezzo, E.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Bianco, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Borgna, I.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia Abstract: The peculiar source characteristics of long-period seismic events (time persistency of the source, low-frequency peaks in the source spectrum, absence of high-frequency radiation) prevent the formation of a definite high-frequency coda in the seismograms. In contrast, this is well formed in volcano–tectonic quakes. For this reason, the widely used duration magnitude scale that is based on the proportionality between the energy and the coda duration cannot be used for long-period estimation. In observatory practice, the long-period magnitude is sometimes estimated using the same duration magnitude scale, leading to confusing results. In this report, we show a new method to estimate the magnitude of long-period events that generally occur for volcanoes, with some application examples from data for Mt Etna (Italy), Colima Volcano (Mexico) and Campi Flegrei (Italy). 2013-04-28T22:00:00Z http://hdl.handle.net/2122/8677 Title: Damage Distribution in L’Aquila City (Central Italy) during the 6 April 2009 Earthquake Authors: Tertulliani, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Leschiutta, I.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Bordoni, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Milana, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia Abstract: The 6 April 2009 Mw 6.3 earthquake (Imax 9–10, Mercalli–Cancani– Sieberg [MCS]) struck the Abruzzi region of central Italy, producing severe damage in the city of L’Aquila. There was heavy damage in the city, especially in the central city area where unusual features of the damage pattern were immediately evident. The aim of this study is to correlate the distribution and the severity of the damage with the geological setting of the area, taking into account the characteristics of the building stock through time. Strong-motion recordings and ambient noise measurements taken soon after the mainshock and during the entire aftershock sequence showed variability in groundmotion amplification throughout the city. Factor of amplification (Fa) results are very high in the southern sector of the city, where the Limi Rossi del Colle dell’Aquila (LRCA) red silts outcrop, and quickly decrease northward, where LRCA is absent. This result correlates with the damage distribution to reinforced concrete (RC) buildings. In the southern sector the rate of collapse of RC buildings was 10%, versus 2% in the rest of the city. General conclusions highlight that the building stock of the city suffered different levels of damage that can be partially explained by the combination of building vulnerability and surface geology. 2012-07-31T22:00:00Z http://hdl.handle.net/2122/8675 Title: The Interreg IV Italia-Austria "SeismoSAT" Project: connecting Seismic Data Centers via satellite Authors: Pesaresi, Damiano; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Lenhardt, Wolfgang; ZAMG; Rauch, Markus; Protezione Civile Bolzano; Zivcic, Mladen; ARSO; Steiner, Rudolf; ZAMG; Fabris, Paolo; OGS; Bertoni, Michele; OGS Editors: Pesaresi, Damiano; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Busby, Robert; IRIS Abstract: Since 2002 the Istituto Nazionale di Oceanografia e di Geofisica Sperimentale - OGS in Udine (Italy), the Zentralanstalt für Meteorologie und Geodynamik (ZAMG) in Vienna (Austria), and the Agencija Republike Slovenije za okolje (ARSO) in Ljubljana (Slovenija) are using the Antelope software suite as the main tool for collecting, analyzing, archiving and exchanging seismic data in real time, initially in the framework of the EU Interreg IIIA project “Trans-national seismological networks in the South-Eastern Alps”. The data exchange has proved to be effective and very useful in case of seismic events near the borders between Italy, Austria and Slovenia, where the poor single national seismic networks coverage precluded a correct localization, while the usage of common data from the integrated networks improves considerably the overall reliability of real time seismic monitoring of the area. At the moment the data exchange between the seismic data centers relies on internet: this however is not an ideal condition for civil protection purposes, since internet reliability is poor. For this reason in 2012 the Protezione Civile della Provincia Autonoma di Bolzano in Bolzano (Italy) joined OGS, ZAMG and ARSO in the Interreg IV Italia-Austria Project “SeismoSAT” aimed in connecting the seismic data centers in real time via satellite. The general schema of the project, including first data bandwith estimates and a possible architecture will be illustrated. 2013-04-11T22:00:00Z