http://hdl.handle.net/2122/277 Sun, 19 May 2013 22:40:00 GMT 2013-05-19T22:40:00Z http://hdl.handle.net/2122/8662 Title: The Volcano-Seismic Clock of the South American Pacific Margin - A Possible First Link Between Natural Disasters Prevention and Expanding Earth Authors: Scalera, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia Editors: Scalera, Giancarlo; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia Abstract: A volcano-seismic correlation was for a long time suspected to occur on the Pacific margin of South America. Scalera (2008) using the data available in 2006 in the Smithsonian Institution Catalogue of the volcanic eruptions, has revealed evidence that earthquakes happened into the South-American Wadati-Benio zone – with magnitude greater than 8.4 –are associated to an enhanced rate of volcanic eruptions, but has been impossible to determine the causal chain between the two phenomena. After 2006, the effort of the Smithsonian Institution to improve our knowledge of this region has resulted in a greatly increased completeness of the catalogue, adding the new eruptions for the 2000- 2010 interval, but also an additional 50% of new entries in the list of the Andean volcanoes. The occurrence of the Chilean earthquake of Maule – 27 February 2010 (M=8.8); occurred at five decades from the 1960 quake – has been the occasion to rework all the data searching for additional clues able to indicate a preferred causal direction eruptions-earthquakes or earthquakes-eruptions – or from a third more general cause (e.g. a mantle movements) to both eruptions and earthquakes. This short note discusses the three above-said hypotheses and tries to establish if these results could be useful to the aims of the Civil Protection in the programs of prevention and/or forecasting of natural disasters. Fri, 30 Nov 2012 23:00:00 GMT http://hdl.handle.net/2122/8662 2012-11-30T23:00:00Z http://hdl.handle.net/2122/8637 Title: Empirical calibration of local magnitude datasets versus moment magnitude in Italy Authors: Gasperini, P.; Università di Bologna; Lolli, B.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia; Vannucci, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia Abstract: Using general orthogonal regressions (GORs), we calibrated local magnitudes, estimated in Italy using various methods in different periods of time from 1981 to 2010, with a set of homogeneous moment magnitudes (Mw). Magnitude uncertainties, necessary for the application of GOR methods, are inferred by a trial-anderror procedure based on a priori information and empirical regression results. We found that local magnitudes determined using real or synthesized Wood–Anderson waveforms (ML) scale 1:1 with Mw in most cases but in general underestimate Mw by about 0.1–0.2 magnitude units. The only significant deviation from the 1:1 scaling concerns the most recent data provided by the online ISIDE bulletin of the Istituto Nazionale di Geofisica e Vulcanologia and is probably due to the use of a distance correction table (−log A0) not fully appropriate for the Italian area. Magnitudes computed from the duration of the seismogram coda (MD) do not generally scale 1:1 with Mw and are also underestimated. The relevant regression coefficients vary significantly from one data set to another depending on the empirical formulas used by different catalogs and bulletins. The derived regression coefficients are used to build a homogenized catalog in terms of Mw that also includes a consistent estimate of uncertainty for all reported magnitudes. The analysis of the frequency–magnitude distribution of the resulting catalog, covering 30 years of data, shows a b-value slightly lower than 1, which is reasonably uniform over the different time intervals and data sets. It also shows a progressive decay of the earthquake rates below the best-fit straight line for Mw >4:5 that might reflect a magnitude distribution truncated or tapered to relatively small maximum magnitudes for some Italian seismic zones with low activity. This behavior also seems to exclude a characteristic earthquake recurrence mechanism for Italy. Mon, 31 Dec 2012 23:00:00 GMT http://hdl.handle.net/2122/8637 2012-12-31T23:00:00Z http://hdl.handle.net/2122/8625 Title: Toward Reliable Characterization of Sites With Pronounced Topography and Related Effects on Ground Motion Authors: Burianek, J; ETH Zurigo; Cauzzi, C; ETH Zurigo; Fah, D; ETH Zurigo; Bard, P.Y.; ISTerre; Cornou, C; ISTerre; Pitilakis, K; University of Thessaloniki; Massa, Marco; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Milano-Pavia, Milano, Italia; Theodulidis, N; Institute of Engineering Seismology and Earthquake Engineering, Thessaloniki; Bertrand, E; CETE Editors: WCEE proceedings Abstract: Here we present first results of a joint effort undertaken in ongoing European project NERA -JRA1, which aims at establishing scientifically solid and practically acceptable propositions to incorporate surface topography effects in seismic hazard estimates. We assembled a dataset of both ambient vibration and earthquake recordings acquired at 40 European sites with pronounced topography. It comprises a wide variety of sites including populated hills and even extreme cases of unstable rock slopes in Alpine regions. Results of the polarisation analysis for the two sites presented here show the peculiarity of the topographic site effects. Tue, 24 Sep 2013 22:00:00 GMT http://hdl.handle.net/2122/8625 2013-09-24T22:00:00Z http://hdl.handle.net/2122/8624 Title: Seismic amplification in presence of topography and their consequences for ground motion predictions and seismic code for building: the case of Italy Authors: Massa, Marco; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Milano-Pavia, Milano, Italia; Lovati, Sara; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Milano-Pavia, Milano, Italia; Barani, Simone; Università di Genova Editors: WCEE proceedings Abstract: This work talks about the relevance of topographic effects in local site response evaluations. In this way some Italian test sites, characterized by the presence of a seismic station installed at the top of a steep topography, were investigated. The influence of the morphology was evaluated, at first, by performing rotational spectral ratio analyses, both in term of single station measurements (i.e. horizontal to vertical spectral ratio, HVSR) and, if possible, also considering reference sites (i.e.standard spectral ratio, SSR) and, at second, evaluating the residuals (logarithmic difference between observed and predicted data) estimated in term of acceleration response spectra for period up to 2.0 s. In this way, the ground motion prediction equations calibrated for Italy by Bindi et al., 2010 were considered. Finally, in correspondence of two selected topographies with seismic stations installed both at the top and at the base, the design elastic acceleration response spectra as proposed by the Italian seismic regulations (NTC, 2008) were evaluated in terms of shape and amplitude. Tue, 24 Sep 2013 22:00:00 GMT http://hdl.handle.net/2122/8624 2013-09-24T22:00:00Z http://hdl.handle.net/2122/8623 Title: Topographic Effects in Probabilistic Seismic Hazard Analysis: The Case of Narni, Central Italy Authors: Barani, Simone; Università Genova; Massa, Marco; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Milano-Pavia, Milano, Italia; Lovati, Sara; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Milano-Pavia, Milano, Italia; Ferretti, Gabriele; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Milano-Pavia, Milano, Italia Editors: WCEE proceedings Abstract: This study presents a probabilistic method for estimating the ground motion hazard at sites presenting topographic irregularities. This method is applicable to topographic crests or ridges which may affect site response, producing 2D (or 3D) amplification effects. The method is based on a set of 2D numerical analyses that are carried out using multiple accelerograms from worldwide weak and strong earthquakes recorded on rock. Numerical analyses are performed to compute site-specific frequency-dependent amplification factors to be included into the ground motion prediction equation used in the seismic hazard computation. The hazard at the top of the ridge is then assessed by running a conventional probabilistic seismic hazard analysis (PSHA) with the attenuation relationship modified to include the site response. An application to the case study of Narni (Central Italy) is presented in this work. Tue, 24 Sep 2013 22:00:00 GMT http://hdl.handle.net/2122/8623 2013-09-24T22:00:00Z http://hdl.handle.net/2122/8622 Title: Real Time acquisition and processing of strong motion data in Northern Italy: the RAIS network. Authors: Massa, Marco; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Milano-Pavia, Milano, Italia; Lovati, Sara; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Milano-Pavia, Milano, Italia; Franceschina, Gian Lorenzo; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Milano-Pavia, Milano, Italia; Augliera, Paolo; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Milano-Pavia, Milano, Italia Editors: WCEE proceedings Abstract: This work summarizes the characteristics of a strong motion network (RAIS, in Italian: “Rete Accelerometrica in Italia Settentrionale”, Strong Motion Network in Northern Italy) installed in northern Italy since 2006. The main goal of the RAIS is both to collect data with a wide range of magnitude, allowing us to increase the knowledge of the covered area, and to assure real time high quality data in case of strong events. For each recorded earthquake data are automatically processed in order to fast disseminate the most important ground motion parameters (peak ground acceleration and velocity, 5% damped acceleration, pseudo-velocity and relative response spectra, Arias and Housner intensities). Moreover, for each event, at each recording site, the Horizontal to Vertical Spectral Ratio are calculated. The analysis and metadata related to each event are collected in a web site (http://rais.mi.ingv.it) while the waveforms are distributed at different data center. Tue, 24 Sep 2013 22:00:00 GMT http://hdl.handle.net/2122/8622 2013-09-24T22:00:00Z http://hdl.handle.net/2122/8621 Title: Qui INGV Authors: Pacor, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Milano-Pavia, Milano, Italia; Massa, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Milano-Pavia, Milano, Italia; Luzi, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Milano-Pavia, Milano, Italia; Augliera, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Milano-Pavia, Milano, Italia; Puglia, R.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Milano-Pavia, Milano, Italia; Lovati, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Milano-Pavia, Milano, Italia; Franceschina, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Milano-Pavia, Milano, Italia; Ameri, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Milano-Pavia, Milano, Italia Abstract: L’INGV, a partire dal 2006, ha iniziato una fase di potenziamento del monitoraggio accelerometrico, installando nelle aree centrali della pianura padana 22 sensori strong-motion (Rete Accelerometrica Italia Settentrionale, RAIS, http://rais.mi.ingv.it/). Dal 2008, sensori accelerometrici sono stati via via installati in 105 siti a Rete Sismica Nazionale (RSN), gestita dal Centro Nazionale Terremoti (CNT). Nel complesso le 127 stazioni accelerometriche presenti sul territorio nazionale costituiscono a tutti gli effetti la rete accelerometrica nazionale INGV. I dati acquisiti da tutte le stazioni accelerometriche sono attualmente distribuiti in tempo reale tramite il portale EIDA (European Integrated Data Archive; http://eida.rm.ingv.it/) e sono principalmente utilizzati per il calcolo delle Shakemaps a scala nazionale. Attualmente, l’INGV sta realizzando un portale web per la distribuzione dei dati accelerometrici registrati dalle stazioni INGV, composto da 2 moduli distinti: il primo, denominato ISMD, ha lo scopo di archiviaziare e distribuire in tempo quasi reale (poche ore dopo l’evento) le forme d’onda accelerometriche in formato non corretto ed i relativi metadati ottenuti a seguito di una procedura di processamento automatico; il secondo, denominato DYNA, è una banca dati relazionale, contenente le forme d’onda di accelerazione, velocità e spostamento e gli spettri di risposta di accelerazione, ottenuti attraverso il processamento manuale dei segnali non corretti, oltre ai relativi metadati associati agli eventi sismici ed alle stazioni di registrazione Il prototipo del portale dei dati accelerometrici INGV (Figura 1) è stato pubblicato lo scorso maggio, a seguito della sequenza sismica Emiliana. Mon, 30 Apr 2012 22:00:00 GMT http://hdl.handle.net/2122/8621 2012-04-30T22:00:00Z http://hdl.handle.net/2122/8610 Title: Trioctahedral micas in xenolithic ejecta from recent volcanism of the Somma-Vesuvius (Italy): crystal chemistry and genetic inferences. Authors: Balassone, G.; Dipartimento di Scienze della Terra, Università “Federico II”, via Mezzocannone 8, I-80134 Napoli, Italy; Scordari, F.; Dipartimento di Scienze della Terra e Geoambientali, Università degli Studi di Bari, via Orabona 4, I-70125 Bari, Italy; Lacalamita, M.; Dipartimento di Scienze della Terra e Geoambientali, Università degli Studi di Bari, via Orabona 4, I-70125 Bari, Italy; Schingaro, M.; Dipartimento di Scienze della Terra e Geoambientali, Università degli Studi di Bari, via Orabona 4, I-70125 Bari, Italy; Mormone, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Piochi, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Petti, C.; Dipartimento di Scienze della Terra, Università “Federico II”, via Mezzocannone 8, I-80134 Napoli, Italy; Mondillo, N.; Centro Museale “Musei delle Scienze Naturali”, Università “Federico II”, via Mezzocannone 8, I-80134 Napoli, Italy Abstract: This study reports the first crystal chemical database resulting from a detailed structural investigation of trioctahedral micas found in xenolithic ejecta produced during the AD 1631, 1872 and 1944 eruptions, three explosive episodes of recent volcanic period of Vesuvius volcano (Southern Italy). Three xenolith types were selected: metamorphic/metasomatic skarns, pyrometamorphic/hydrothermally altered nodules and mafic cumulates. They are related to different magma chemistry and effusive styles: from sub-plinian and most evolved (AD 1631 eruption) to violent strombolian with medium evolution degree (AD 1872 eruption) to vulcanian-effusive, least evolved (AD 1944 eruption) event, respectively. Both xenoliths and micas were investigated employing multiple techniques: the xenoliths were characterized by X-ray fluorescence, inductively-coupled plasma-mass spectrometry, optical microscopy, X-ray powder diffraction, and quantitative energy-dispersive microanalysis; the micas were studied by electron probe microanalysis and single crystal X-ray diffraction. The mica-bearing xenoliths showvariable texture and mineralogical assemblage, clearly related to their different origin. Based on the major oxide chemistry, only one xenolithic sample falls in the skarn compositional field fromthe Somma-Vesuvius literature, some fall close to the skarns and cumulate fields, others plot close to the syenite/foidolite/essexite field. A subgroup of the selected ejecta does not fall or approach any of the compositional fields. Trace and rare earth element patterns show some petrological affinity between studied xenoliths and erupted magmas with typical Eu, Ta and Nb negative anomalies. Strongly depleted patterns were detected for the 1631 metamorphic/metasomatic skarns xenoliths. Three distinct mica groups were distinguished: 1) Mg-, Al-rich, low Ti-bearing, low to moderate F-bearing varieties (1631 xenolith), 2) Al-moderate, F- and Mg-rich, Ti-, Fe-poor varieties (1872 xenolith), and 3) Al-, Ti- and Fe-rich, F-poor phases (1944 xenolith). All the analyzed mica crystals are 1Mpolytypes with the expected space group C2/m. Micas from xenoliths of the 1631 Vesuvius eruption are phlogopites characterized by a combination of low extent of oxy-type and variable extent OH−→F− substitutions, as testified by the range of F concentration (from ~0.20 to 0.80 apfu). Micas from xenoliths of the 1872 Vesuvius eruption exhibit structural peculiarities typical of fluorophlogopites, i.e. OH−→F− substitution is predominant. Micas from the xenolith of the 1944 Vesuvius eruption display features typical of oxy-substituted micas. The variability of the crystal chemical features of the studied micas is consistentwith the remarkable variation of their host rocks. Micas from1631 nodules are related to metasomatic, skarn-type environment, deriving from the metamorphosed wall-rocks hosting the magma reservoir. The fluorophlogopites from the 1872 xenoliths testify for strongly dehydrated environmental conditions compared to those of the 1631 and 1944 hosts. Finally, magma storage condition at depth, associated to a decreasing aH2O may have promoted major oxy-type substitutions in 1944 biotites. Mon, 31 Dec 2012 23:00:00 GMT http://hdl.handle.net/2122/8610 2012-12-31T23:00:00Z http://hdl.handle.net/2122/8609 Title: Enhanced crystal fabric analysis of a lava flow sample by neutron texture diffraction: A case study from the Castello d’Ischia dome Authors: Walter, J. M.; Mineralogisch-Petrologisches Institut, Universität Bonn, Poppelsdorfer Schloss, D-53115, Bonn,; Iezzi, G.; Dipartimento di Ingegneria e Geologia (INGEO), Università G. d’Annunzio, Chieti, Italy; Albertini, G.; Dipartimento di Fisica e Ingegneria dei Materiali e del Territorio, Università Politecnica delle Marche,; Gunther, M. E.; Department of Geological Sciences, University of Idaho, Moscow, Idaho, USA; Piochi, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Ventura, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Jansen, E.; Mineralogisch-Petrologisches Institut, Universität Bonn, Bonn, Germany; Fiori, F.; Di.S.C.O., Sez. di Biochimica, Biologia e Fisica, Università Politecnica delle Marce, Ancona, Italy Abstract: The crystal fabric of a lava has been analyzed for the first time by neutron texture diffraction. In this study we quantitatively investigate the crystallographic preferred orientation of feldspars in the Castello d’Ischia (Ischia Island, Italy) trachytic exogenous dome. The crystallographic preferred orientation was measured with the monochromatic neutron texture diffractometer SV7 at the Forschungszentrum Jülich in Germany and a Rietveld refinement was applied to the sum diffraction pattern. The complementary thin section analysis showed that the three-dimensional crystal shape and the corresponding shape preferred orientation are in agreement with the quantitative orientation distributions of the neutron texture data. The (0k0) crystallographic planes of the feldspars are roughly parallel to the local flow bands, whereas the other corresponding pole figures show that a pivotal rotation of the anorthoclase and sanidine crystals was active during the emplacement of this lava dome. In combination with scanning electron microscopy investigations, electron probe microanalysis, XRF, and X-ray diffraction, the Rietveld refinement of the neutron diffraction data indicates a slow cooling dynamic on the order of several months during their crystallization under subaerial conditions. Results attained here demonstrate that neutron texture diffraction is a powerful tool that can be applied to lava flows. Wed, 30 Jan 2013 23:00:00 GMT http://hdl.handle.net/2122/8609 2013-01-30T23:00:00Z http://hdl.handle.net/2122/8602 Title: The building up process of a macroseismic intensity database Authors: Mario, Locati; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Milano-Pavia, Milano, Italia; Daniele, Viganò; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Milano-Pavia, Milano, Italia Abstract: Since the late nineties Italy has a well-established tradition of making available on the Internet a national macroseismic intensity database. The last updated version called DBMI11 was released in December 2011. By using this public database everyone can obtain information about the effects caused in a populated place by an earthquake of the past. A huge quantity of well organised historical information can be effortlessly retrieved and used as the background information of the seismic hazard assessment. Other similar activities are carried out by the same DBMI working group: the creation of a transnational European database called AHEAD (Archive of historical Earthquake Data) and the related effort of supporting the growth of other European intensity databases (Catalonia, Spain, Portugal, Greece and UK) and, at world-wide scale, the support for the "Global Earthquake History", the GEM (Global Earthquake Model) global component. This presentation will describe how these databases are built, how they are structured and which tools are used both for managing data and for the Internet publication. Mon, 11 Jun 2012 22:00:00 GMT http://hdl.handle.net/2122/8602 2012-06-11T22:00:00Z