http://hdl.handle.net/2122/249 2013-05-21T20:05:24Z http://hdl.handle.net/2122/8652 Title: A Multidisciplinary Study of the DPRK Nuclear Tests Authors: Carluccio, R.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Giuntini, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Materni, V.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Chiappini, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Bignami, C.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; D'Ajello Caracciolo, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Pignatelli, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Stramondo, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Console, R.; Chiappini, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia Abstract: The Democratic People Republic of Korea announced two underground nuclear tests carried out in their territory respectively on October 9th, 2006 and May 25th, 2009. The scarce information on the precise location and the size of those explosions has stimulated various kinds of studies,mostly based on seismological observations, by several national agencies concerned with theNuclear Test Ban Treaty verification.Weanalysed the available seismological data collected through a global high-quality network for the two tests. After picking up the arrival times at the various stations, a standard location program has been applied to the observed data. If we use all the available data for each single event, due to the different magnitude and different number of available stations, the locations appear quite different. On the contrary, if we use only the common stations, they happen to be only few km apart from each other and within their respective error ellipses. A more accurate relative location has been carried out by the application of algorithms such as double difference joint hypocenter determination (DDJHD) and waveform alignment. The epicentral distance between the two events obtained by these methods is 2 km, with the 2006 event shifted to the ESE with respect to that of 2009. We then used a dataset of VHR TerraSAR-X satellite images to detect possible surface effects of the underground tests. This is the first ever case where these highly performing SAR data have been used to such aim. We applied InSAR processing technique to fully exploit the capabilities of SAR data to measure very short displacements over large areas. Two interferograms have been computed, one co-event and one post-event, to remove possible residual topographic signals. A clear displacement pattern has been highlighted over a mountainous area within the investigated region, measuring a maximum displacement of about 45 mm overall the relief. Hypothesizing that the 2009 nuclear test had been carried out close to the area where the displacement has been observed through the DInSAR technique, its relation with the epicenter location obtained through seismological processing has been discussed as a possible alternative hypothesis with respect to the preferred solutions reported by the nuclear explosion database (NEDB). The distance of about 10 km between the two places can be considered acceptable in light of the possible systematic location shifts commonly observed in the seismological practice over a global scale. The difference between the mb magnitudes of the two tests could reflect differences in geological conditions of the two test sites, even if the yield of the two explosions had been the same. 2012-12-28T23:00:00Z http://hdl.handle.net/2122/8532 Title: Rete Mobile e Laboratorio Analisi aVanzate (LAV) - Rendiconto 2012 Authors: Cusano, P.; 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; Petrosino, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Bianco, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Castellano, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Del Pezzo, E.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia Abstract: In the text 2012-12-31T23:00:00Z http://hdl.handle.net/2122/8531 Title: Rete Mobile e Laboratorio Analisi aVanzate (LAV) - Rendiconto I semestre 2012 Authors: Cusano, P.; 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; Petrosino, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Bianco, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Castellano, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Del Pezzo, E.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia Abstract: In the text 2012-06-30T22:00:00Z http://hdl.handle.net/2122/8507 Title: Pianificazione e preparazione dell’emergenza. L’esercitazione a Santa Sofia (FC) del 26/30 settembre 2011: un esempio di gestione di una crisi sismica Authors: Moretti, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Cattaneo, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Pondrelli, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia; Margheriti, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Govoni, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Nostro, C.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Camassi, R.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia; Selvaggi, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Santa Sofia Team, .; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Santa Sofia Team, .; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia; Santa Sofia Team, .; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Milano-Pavia, Milano, Italia; Santa Sofia Team, .; Istituto Nazionale di Geofisica e Vulcanologia, Sezione AC, Roma, Italia Abstract: Nell’ambito della convenzione vigente tra l’Istituto Nazionale di Geofisica e Vulcanologia (INGV) e l’Agenzia di Protezione Civile della Regione Emilia Romagna è stata realizzata a fine settembre del 2011 una esercitazione sul rischio sismico con l’obiettivo di valutare il livello raggiunto nelle procedure che entrambi gli Enti attivano in occasione di una emergenza a seguito di un forte terremoto. La simulazione ha interessato oltre 50 unità di personale INGV, sia in sede che in area epicentrale, appartenenti a diverse Sezioni e sedi INGV (Ancona, Arezzo, Bologna, Irpinia, Milano, Pisa e Roma). La preparazione dell’evento si è fondata sulle esperienze del passato, in primis la lunga emergenza aquilana del 2009 [Margheriti et al., 2010; 2011; Moretti et al., 2011c], con uno sguardo alle nuove esigenze sia interne che esterne (ad esempio le istanze della Protezione Civile). Nonostante gli imprevisti e gli inevitabili errori commessi a cui si aggiunga lo sforzo per mettere insieme tante differenti professionalità e per rispettare sempre al meglio il programma e gli impegni presi con i responsabili dell’Agenzia di Protezione Civile della Regione Emilia Romagna, è stato ampiamente ripagato dall’aver vissuto un’esperienza positiva non solo da un punto di vista professionale ma anche umano. Questa esercitazione si è infatti rivelata un’importante occasione per relazionarsi e confrontarsi con i colleghi solitamente lontani rendendosi conto che da ciascuno di loro è sempre possibile imparare qualcosa. Questa esperienza si è mostrata di fondamentale importanza nella gestione dell’emergenza verificatasi a maggio 2012 in Pianura Padana emiliana [Moretti et al., 2012]. 2013-02-03T23:00:00Z http://hdl.handle.net/2122/8479 Title: Simulazione di un geofono utilizzando pSPICE Authors: Romeo, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Pongetti, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Spinelli, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia Abstract: Questo lavoro studia il modello pSPICE (personal Simulation Program with Integrated Circuit Emphasis) di un geofono. Perché un modello pSPICE? La principale utilità di un modello (che va al di là dello studio asettico della funzione di trasferimento) è quello di interfacciarsi con il dispositivo elettronico che ne estende la risposta (è difficile oggi trovare un sismografo che non sia generosamente aiutato da un qualche misterioso dispositivo di feed-back). Mentre è relativamente facile indurre pSPICE a risolvere semplici problemi meccanici è molto più difficile indurre blasonati simulatori per sistemi meccanici ad incorporare un circuito elettronico. Il lavoro presentato parte da misure fatte su un geofono S-13 per costruirne il modello, che viene verificato con misure reali. Il modello viene usato per studiare il comportamento del geofono simulandone l’invecchiamento del magnete ed il comportamento ad alta frequenza (effetto dell’induttanza della bobina di pick-up). Viene mostrato come interfacciare il modello ad un semplice estensore di banda utilizzando il metodo di Lippmann, e vengono confrontate le risposte del geofono simulato prima e dopo l’espansione di banda. Infine viene simulata la risposta del modello a un terremoto reale, mostrando come operare sul resistore di smorzamento per evitare la saturazione per forti segnali. Questo lavoro può rappresentare il punto di partenza per chi voglia costruire, o soltanto capire, un sismometro a bilanciamento di forze. 2011-12-31T23:00:00Z http://hdl.handle.net/2122/8475 Title: Very detailed seismic pattern and migration inferred from the April 2010 Pietralunga (northern Italian Apennines) micro-earthquake sequence Authors: Marzorati, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Massa, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Milano-Pavia, Milano, Italia; Cattaneo, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Monachesi, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Frapiccini, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia Abstract: We propose a very detailed picture of the seismicity occurring in the proximity of the Alto Tiberina Low Angle Normal Fault (ATF, Northern Italian Apennines) by presenting the pattern and evolution of a seismic sequence that occurred on the hanging wall of the ATF in the first months of 2010 and that was characterized by about 1000 events with ML ranging from -0.7 to 3.8. In order to capture the rupture kinematics of the investigated area, a cross-correlation technique was at first applied to calculate very accurate time shifts among the events of the sequence and then to relocate them. Considering the many factors that can affect the accuracy of a routine event location, the whole sequence was relocated with the double-difference method, including both absolute travel-time measurements and cross-correlation differential travel-times. The new locations confirm that seismic activity is mainly arranged along a NW-SE oriented structure, ranging in depth from 4 to 6 km and dipping towards North East with an angle of about 65°. A further analysis of waveforms similarity was performed at a reference station by merging the capability of the cross-correlation technique and the bridging algorithm. The analysis allows us to group events into several earthquake families (from now on multiplets), 11 of which include at least 10 events with a cross-correlation value higher than 0.9. The detected mutiplets allow us to emphasize the spatial and temporal migration of the sequence occurred along a 307°N strike direction with an averaged propagation velocity of about 0.4 km/day. The normal focal mechanisms obtained from the events with ML≥2 validate the supposed extensional tectonic regime of the investigated area. The main nodal planes, characterized by strikes ranging in 312°±12 and dips about -90°, are consistent with the spatial evolution of the aftershocks. 2011-12-31T23:00:00Z http://hdl.handle.net/2122/8471 Title: A comprehensive approach for evaluating network performance in surface and borehole seismic monitoring Authors: Stabile, T.; Istituto di Metodologie per l’Analisi Ambientale, CNR-IMAA; Iannaccone, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Zollo, A.; Dipartimento di Scienze Fisiche, Università di Napoli Federico II, Naples; Lomax, A.; ALomax Scientific, Mouans-Sartoux, France; Ferulano, F.; ENI S.p.A. - E&P Division, San Donato Milanese (MI), Italy; Vetri, L.; ENI S.p.A. - E&P Division, San Donato Milanese (MI), Italy; Barzaghi, L.; ENI S.p.A. - E&P Division, San Donato Milanese (MI), Italy Abstract: The accurate determination of locations and magnitudes of seismic events in a monitored region is important for many scientific, industrial and military studies and applications; for these purposes a wide variety of seismic networks are deployed throughout the world. It is crucial to know the performance of these networks not only in detecting and locating seismic events of different sizes throughout a specified source region, but also by evaluating their location errors as a function of the magnitude and source location. In this framework, we have developed a method for evaluating network performance in surface and borehole seismic monitoring. For a specified network geometry, station characteristics and a target monitoring volume, the method determines the lowest magnitude of events that the seismic network is able to detect (Mw detect), and locate (Mw loc) and estimates the expected location and origin time errors for a specified magnitude. Many of the features related to the seismic signal recorded at a single station are considered in this methodology, including characteristics of the seismic source, the instrument response, the ambient noise level, wave propagation in a layered, anelastic medium and uncertainties on waveform measures and the velocity model. We applied this method to two different network typologies: a local earthquake monitoring network, Irpinia Seismic Network (ISNet), installed along the Campania-Lucania Apennine chain in Southern Italy, and a hypothetic borehole network for monitoring microfractures induced during the hydrocarbon extraction process in an oil field. The method we present may be used to aid in enhancing existing networks and/or understanding their capabilities, such as for the ISNet case study, or to optimally design the network geometry in specific target regions, as for the borehole network example. 2011-12-31T23:00:00Z http://hdl.handle.net/2122/8432 Title: Results of microtremor measurements in the urban areas of Catania, Italy Authors: Lombardo, G.; Dipartimento di Scienze Geologiche, University of Catania, Italy; Coco, G.; Dipartimento di Scienze Geologiche, University of Catania, Italy; Corrao, M.; Dipartimento di Scienze Geologiche, University of Catania, Italy; Imposa, S.; Dipartimento di Scienze Geologiche, University of Catania, Italy; Azzara, R. M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Cara, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Rovelli, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia Abstract: More than 200 time histories of ambient noise have been recorded at 158 sites in the urban area of Catania. Among them, 144 sites are aligned along 15 profiles crossing the most representative lithologies outcropping in the study area. The standard Nakamura (1989) technique has been applied to compute the H/V spectral ratio along these profiles, where the upper-layer structure has been reconstructed in detail using surface geology surveys as well as data from available wells. The geological peculiarity of Catania is the presence of an extended, high- velocity lava cover of varying thickness that fills a large part of the urban area; lower-velocity sedimentary layers outcrop only in small windows in the northern part of the town, however, they predominate in the southern part. In such a complex geological setting, the application of the Nakamura technique provides results that do not correspond strictly to the expectation for usual hard and soft-site spectral shapes. Measurement results have indicated that, in general, the H/V amplitudes do not attain large values in the study area: only at 15 sites are the spectral peaks greater than 3 units, and this occurs predominantly on lava outcrops, where the maximum amplification occurs between 7 and 10 Hz. This frequency band is consistent with weathering processes of the lava flows. At soft sites the observation of significant amplitude (>3) spectral peaks is limited to a few cases. The recordings of six broad-band stations laying on or near the selected profiles have been used for a preliminary comparison between microtremor results and amplifications observed during individual earthquakes. The H/V spectral ratios are generally similar for microtremor and earthquake data, microtremor tending to underestimate the amplitude of horizontal ground motions of earthquakes. But amplifications at sedimentary outcrops (with reference to a massive lava site) can be significant during individual earthquakes, and in some cases include frequency bands where no tendency to amplify was inferred from the microtremor H/V spectral ratios. Even though this comparison needs more data before reaching a stable conclusion, a preliminary analysis of earthquake data confirms that caution is required in using ambient noise for engineering purposes in complex and laterally sharply varying nearsurface geological structures such as those presented by the urban area of Catania. 2001-08-31T22:00:00Z http://hdl.handle.net/2122/8423 Title: Sesame project - Deliverable D23.12 - WP12 - GUIDELINES FOR THE IMPLEMENTATION OF THE H/V SPECTRAL RATIO TECHNIQUE ON AMBIENT VIBRATIONS MEASUREMENTS, PROCESSING AND INTERPRETATION Authors: Sesame Team; various Abstract: A significant part of damage observed in destructive earthquakes around the world is associated with seismic wave amplification due to local site effects. Site response analysis is therefore a fundamental part of assessing seismic hazard in earthquake prone areas. A number of experiments are required to evaluate local site effects. Among the empirical methods the H/V spectral ratios on ambient vibrations is probably one of the most common approaches. The method, also called the „Nakamura technique“ (Nakamura, 1989), was first introduced by Nogoshi and Igarashi (1971) based on the initial studies of Kanai and Tanaka (1961). Since then, many investigators in different parts of the world have conducted a large number of applications. An important requirement for the implementation of the H/V method is a good knowledge of engineering seismology combined with background information on local geological conditions supported by geophysical and geotechnical data. The method is typically applied in microzonation studies and in the investigation of the local response of specific sites. In the present document, the application of the H/V technique in assessing local site effects due to dynamic earthquake excitations, is the main focus, whereas other applications regarding the static aspects are not considered. In the framework of the European research project SESAME (Site Effects Assessment Using Ambient Excitations: Contract No. EVG1-CT-2000-00026), the use of ambient vibrations in understanding local site effects has been studied in detail. The present guidelines on the H/V spectral ratio technique are the result of comprehensive and detailed analyses performed by the SESAME participants during the last three years. In this respect, the guidelines represent the state-of-the-art of the present knowledge of this method and its applications, and are based on the consensus reached by a large group of participants. It reflects the synthesis of a considerable amount of data collection and subsequent analysis and interpretations. In general, due to the experimental character of the H/V method, the absolute values obtained for a given site require careful examination. In this respect visual inspection of the data both during data collection and processing is necessary. Especially during the interpretation of the results there should be frequent interaction with regard to the choices of the parameters for processing. The guidelines presented here outline the recommendations that should be taken into account in studies of local site effects using the H/V technique on ambient vibrations. The recommendations given apply basically for the case where the method is used alone in assessing the natural frequency of sites of interest and are therefore based on a rather strict set of criteria. The recommended use of the H/V method is however, to combine several other geophysical and geotechnical approaches with sufficient understanding of the local geological conditions. In such a case, the interpretation of the H/V results can be improved significantly in the light of the complementary data. The guidelines are organised in two separate parts; the quick field reference and interpretation guidelines (Part I) and detailed technical guidelines (Part II). Part I aims to summarise the most critical factors that influence the data collection, analysis and interpretation and provides schematic recommendations on the interpretation of results. Part II includes a detailed description of the technical requirements, standard data processing and the interpretation of results. Several examples of the criteria described in Part I and II are given in Appendix A. In addition, some physical explanations of the results based on theoretical considerations are given in Appendix B. In Part II, section 1, the results of the experiments performed within the framework of the SESAME project are given in smaller fonts to separate these from the recommendations and the explanations given in the guidelines. The word „soil“ should be considered as a generic term used throughout the text to refer to all kinds of deposits overlying bedrock without taking into account their specific origin. The processing software J-SESAME developed specifically for using in H/V technique, is explained (provided on a separate CD accompanying the guidelines) in Part II. However, the recommendations given in the guidelines are meant for general application of the method with any other similar software. J-SESAME is provided as a tool for the easy implementation of the recommendations outlined in this document. Regarding the processing of the data, several options can be chosen, but the recommended processing options are provided as defaults by the J-SESAME software. 2004-11-30T23:00:00Z http://hdl.handle.net/2122/8414 Title: Sesame Project - Deliverable D08-02 - WP02 H/V technique : experimental conditions - Final report on Measurement Guidelines Authors: Atakan, Kuvvet; University of Bergen, Norway; Azzara, RIccardo Mario; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Bard, Pierre-Yves; LGIT, Grenoble, France; Bonnefoy-Claudet, Sylvette; LGIT, Grenoble, France; Borges, Antonio; ICTE, Lisbon, Portugal; Bottger Sorenses, Mathilde; University of Bergen, Norway; Cara, Fabrizio; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Chatelain, Jean-Luc; LGIT, Grenoble, France; Cultrera, Giovanna; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Di Giulio, Giuseppe; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Dunand, Francois; LGIT, Grenoble, France; Duval, Anne-Marie; CETE, Nice, France; Faeh, Donat; ETHZ, Zurich, Swiss; Gueguen, Philippe; LGIT, Grenoble, France; Guillier, Bertrand; LGIT, Grenoble, France; Ripperger, Johannes; ETHZ, Zurich, Swiss; Teves-Costa, Paula; ICTE, Lisbon, Portugal; Vassiliades, Jean-Francois; CETE, Nice, France; Vidal, Sylvain; CETE, Nice, France; Wassner, Jochen; ETHZ, Zurich, Swiss Abstract: In the following we report the final results for WP02-Measurement Guidelines. This work was conducted under the framework of the SESAME Project (Site Effects Assessment Using Ambient Excitations, EC-RGD, Project No. EVG1-CT-2000-00026 SESAME), Task A (H/V technique), Work Package 02 (WP02 – Measurement Guidelines). 2003-06-30T22:00:00Z