http://hdl.handle.net/2122/1054 Thu, 23 May 2013 21:55:05 GMT 2013-05-23T21:55:05Z 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. Mon, 08 Apr 2013 22:00:00 GMT http://hdl.handle.net/2122/8704 2013-04-08T22:00:00Z http://hdl.handle.net/2122/8590 Title: Overview on the strong motion data recorded during the May-June 2012 Emilia seismic sequence Authors: Luzi, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Milano-Pavia, Milano, Italia; Pacor, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Milano-Pavia, Milano, Italia; Ameri, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Milano-Pavia, Milano, Italia; Puglia, R.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Milano-Pavia, Milano, Italia; Burrato, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Massa, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Milano-Pavia, Milano, Italia; Augliera, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Milano-Pavia, Milano, Italia; Franceschina, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Milano-Pavia, Milano, Italia; Lovati, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Milano-Pavia, Milano, Italia; Castro, R.; Departamento de Sismología, División Ciencias de la Tierra, centro de Investigación Científica y de Educación Superior de Ensenada (CICESE), Ensenada, Baja California, 22860, México. Abstract: 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. Mon, 31 Dec 2012 23:00:00 GMT http://hdl.handle.net/2122/8590 2012-12-31T23:00:00Z http://hdl.handle.net/2122/8579 Title: Probabilistic Seismic Hazard Assessment: Combining Cornell-like approaches and data at sites through Bayesian inference Authors: Selva, J.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia; Sandri, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia Abstract: The societal importance and implications of seismic hazard assessment forces the scientific community to pay an increasing attention to the evaluation of uncertainty, to provide accurate assessments. Probabilistic Seismic Hazard Assessment (PSHA) formally accounts for the natural variability of the involved phenomena, from seismic sources to wave propagation. Recently, an increasing attention is paid to the consequences that alternative modeling procedures have on hazard results. This uncertainty, essentially of epistemic nature, has been shown to have major impacts on PSHA results, leading to extensive applications of techniques like the Logic Tree. Here, we develop a formal Bayesian inference scheme for PSHA that allows, on one side, to explicitly account for all uncertainties and, on the other side, to consider a larger set of sources of information, from heterogeneous models to past data. This process decreases the chance of undesirable biases, and leads to a controlled increase of the precision of the probabilistic assessment. In addition, the proposed Bayesian scheme allows (i) the assignment of a ’subjective’ reliability to single models, without requirement of completeness or homogeneity, and (ii) a transparent and uniform evaluation of the ’strength’ of each piece of information used on the final results. The applicability of the method is demonstrated through the assessment of seismic hazard in the Emilia-Romagna region (Northern Italy), in which the results of a traditional Cornell-McGuire hazard model based on a Logic Tree are locally updated with the historical macroseismic records, to provide a unified assessment that accounts for both sources of information. Mon, 31 Dec 2012 23:00:00 GMT http://hdl.handle.net/2122/8579 2012-12-31T23:00:00Z http://hdl.handle.net/2122/8569 Title: Long-term multi-risk assessment: statistical treatment of interaction among risks Authors: Selva, J.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia Abstract: Multi-risk approaches have been recently proposed to assess and compare different risks in the same target area. The key points of multi-risk assessment are the development of homogeneous risk definitions and the treatment of risk interaction. The lack of treatment of interaction may lead to significant biases and thus to erroneous risk hierarchization, which is one of primary output of risk assessments for decision makers. In this paper, a formal statistical model is developed to treat interaction between two different hazardous phenomena in long-term multi-risk assessments, accounting for possible effects of interaction at hazard, vulnerability and exposure levels. The applicability of the methodology is demonstrated through two illustrative examples, dealing with the influence of (1) volcanic ash in seismic risk and (2) local earthquakes in tsunami risk. In these applications, the bias in single-risk estimation induced by the assumption of independence among risks is explicitly assessed. An extensive application of this methodology at regional and sub-regional scale would allow to identify when and where a given interaction has significant effects in long-term risk assessments, and thus, it should be considered in multi-risk analyses and risks hierarchization. Mon, 04 Mar 2013 23:00:00 GMT http://hdl.handle.net/2122/8569 2013-03-04T23:00:00Z http://hdl.handle.net/2122/8568 Title: Impact on loss/risk assessments of inter-model variability in vulnerability analysis Authors: Selva, J.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia; Argyroudis, S.; Aristotle University of Thessaloniki; Pitilakis, k.; Aristotle University of Thessaloniki Abstract: Fragility curves (FCs) constitute an emerging tool for the seismic risk assessment of all elements at risk. They express the probability of a structure being damaged beyond a specific damage state for a given seismic input motion parameter, incorporating the most important sources of uncertainties, that is, seismic demand, capacity and definition of damage states. Nevertheless, the implementation of FCs in loss/risk assessments introduces other important sources of uncertainty, related to the usually limited knowledge about the elements at risk (e.g., inventory, typology). In this paper, within a Bayesian framework, it is developed a general methodology to combine into a single model (Bayesian combined model, BCM) the information provided by multiple FC models, weighting them according to their credibility/ applicability, and independent past data. This combination enables to efficiently capture inter-model variability (IMV) and to propagate it into risk/loss assessments, allowing the treatment of a large spectrum of vulnerability-related uncertainties, usually neglected. As case study, FCs for shallow tunnels in alluvial deposits, when subjected to transversal seismic loading, are developed with two conventional procedures, based on a quasi-static numerical approach. Noteworthy, loss/risk assessments resulting from such conventional methods show significant unexpected differences. Conventional fragilities are then combined in a Bayesian framework, in which also probability values are treated as random variables, characterized by their probability density functions. The results show that BCM efficiently projects the whole variability of input models into risk/loss estimations. This demonstrates that BCM is a suitable framework to treat IMV in vulnerability assessments, in a straightforward and explicit manner. Sun, 03 Mar 2013 23:00:00 GMT http://hdl.handle.net/2122/8568 2013-03-03T23:00:00Z http://hdl.handle.net/2122/8567 Title: The revision of the October 30, 1901 earthquake, west of Lake Garda (northern Italy) Authors: Pessina, V.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Milano-Pavia, Milano, Italia; Tertulliani, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Camassi, R.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia; Rossi, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Scardia, G.; Istituto di Geologia Ambientale e Geoingegneria - CNR, Monterotondo Scalo (Roma) Abstract: On November 24, 2004 an earthquake ( M w = 5.0) struck the west side of Lake Garda (northern Italy), producing moderate but widespread damage. It provided the opportunity of reviewing the seismicity of all the area over the past two centuries, whose former most significant event is the October 30, 1901 earthquake ( M w = 5.5), while other minor but damaging events are the January 5, 1892 ( M w =5.0) and November 16, 1898 ( M w =4.6) earthquakes. On the reviewing we found common similarities in ground shaking distribution as recurrent damaged spots, amplification zones due to local site condition or energy radiation. We believe that these findings are suitable to provide information for provisional purposes in low hazard level area hampered by the lack of knowledge about the seismic sources. New data are provided both in MCS scale and EMS. The sensitivity of a source parameters estimation technique was evaluated for the major event. Mon, 31 Dec 2012 23:00:00 GMT http://hdl.handle.net/2122/8567 2012-12-31T23:00:00Z http://hdl.handle.net/2122/8562 Title: CRISIS2008: A Flexible Tool to Perform Probabilistic Seismic Hazard Assessment Authors: Ordaz, M.; Martinelli, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Milano-Pavia, Milano, Italia; D'Amico, V.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Milano-Pavia, Milano, Italia; Meletti, C.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Milano-Pavia, Milano, Italia Abstract: In the frame of the Italian research project INGV-DPC S2 (http://nuovoprogettoesse2.stru.polimi.it/), funded by the Dipartimento della Protezione Civile (DPC; National Civil Protection Department) within the agreement 2007-2009, a tool for probabilistic seismic hazard assessment (PSHA) was developed. The main goal of the project was to provide a flexible computational tool for PSHA; the requirements considered essential for the success of the project included: • ability to handle both stationary and non-stationary earthquake time-occurrence models; • ability to use ground-motion prediction models that are not parametric equations but probabilistic "footprints" of the intensities generated by earthquakes of known magnitude and focal characteristics. Usually, these footprints are results of ground motion simulations. Some commonly used programs (e.g., FRISK, by McGuire, 1978; SEISRISK III, by Bender and Perkins, 1987) and more recent and state-of-the-art tools (e.g. OpenSHA, by Field et al., 2003, http://www.opensha.org; OpenQuake, http://openquake.org) for PSHA were analyzed. It was decided to focus on CRISIS2007, which was already a mature and well known application (e.g., Kalyan Kumar and Dodagoudar, 2011; Teraphan et al., 2011; D’Amico et al., 2012; see also http://ecapra.org/CRISIS-2007), but also suitable for additional development and evolution since its source code is freely available on request. The computational tool resulted in an extensive redesign and renovation of the previous CRISIS2007 version. CRISIS is a computer program for PSHA, originally developed in the late 1980's using Fortran as programming language (Ordaz, 1991). In this format, still without a graphical user interface (GUI), it was distributed as part of SEISAN tools (Ottemöller et al., 2011). Ten years later, a GUI was constructed, generating what was called CRISIS99 (Ordaz, 1999). In this version, all the graphic features were written in Visual Basic, but the computation engine remained a Fortran dynamic link library. The reason for the use of mixed-language programming was that computations in Visual Basic were extremely slow. Around 2007 the program was upgraded, in view of the advantages offered by the object-oriented technologies. An object-oriented programming language was required and the natural choice was Visual Basic.Net. In the new version (called CRISIS2007), both the GUI and the computation engine were written in the same language. Finally, in the frame of the mentioned S2 project, starting from 2008, the program was split into two logical layers: core (CRISIS Core Library) and presentation (CRISIS2008). In addition, a new presentation layer was developed for accessing the same functionalities via Web (CRISISWeb). It is worth noting that CRISIS has been mainly written by people that are, at the same time, PSHA practitioners. Therefore, the development loop has been relatively short, and most of the modifications and improvements have been made to satisfy the needs of the developers themselves. Tue, 30 Apr 2013 22:00:00 GMT http://hdl.handle.net/2122/8562 2013-04-30T22:00:00Z http://hdl.handle.net/2122/8561 Title: I terremoti del maggio 2012 e la pericolosità sismica dell’area: che cosa è stato sottostimato? Authors: Stucchi, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Milano-Pavia, Milano, Italia; Meletti, C.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Milano-Pavia, Milano, Italia; Bazzurro, P.; IUSS Pavia; Camassi, R.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia; Crowley, H.; Fondazione GEM; Pagani, M.; Fondazione GEM; Pinho, R.; Fondazione GEM; Calvi, G. M.; IUSS Pavia Abstract: Analogamente al caso del terremoto di L’Aquila 2009, immediatamente dopo il terremoto dello scorso maggio 2012 in Emilia, stampa, funzionari pubblici e ricercatori dichiararono che la pericolosità sismica della zona danneggiata, e probabilmente anche il rischio sismico, sono stati sottostimati dalla valutazione probabilistica della pericolosità sismica (PSHA) di riferimento per il territorio Italiano e, di conseguenza, dalle norme tecniche basate su quella valutazione. Una delle principali problematiche emerse è legata al fatto che i valori di PGA registrati vicino a Mirandola erano superiori a quelli “previsti” dalla valutazione di pericolosità sismica. Questo articolo evidenzia alcune delle critiche, mostrando come nei sopraccitati confronti non si considerano le differenze fra le condizioni locali delle stazioni di registrazione e quelle con cui la PSHA è stata calcolata. In aggiunta, l’articolo ricorda che il confronto dei parametri di un singolo evento con la predizione probabilistica di tali parametri ha scarso significato. La causa principale del danno deve essere ricercata nel fatto che le norme di progetto per le costruzioni non sono state implementate nell’area danneggiata prima del 2003 e, per alcuni aspetti, neanche dopo. Perciò quello che è stato realmente sottostimato, non in ambito scientifico, è la necessità di ridurre il rischio sismico. Sat, 31 Dec 2011 23:00:00 GMT http://hdl.handle.net/2122/8561 2011-12-31T23:00:00Z http://hdl.handle.net/2122/8559 Title: A reappraisal of seismic Q evaluated in Campi Flegrei caldera. Receipt for the application to risk analysis 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 Abstract: The civil defense of Italy and the European community have planned to reformulate the volcanic risk in several volcanic areas of Italy, among which Mt. Vesuvius and Campi Flegrei, by taking into account the possible occurrence of damaging pre- or syn-eruptive seismic events. Necessary to achieve this goal is the detailed knowledge of the local attenuation–distance relations. In the present note, we make a survey of the estimates of seismic quality factor (the inverse is proportional to the attenuation coefficient with distance) reported in literature for the area of Campi Flegrei where many, but sometimes contradictory results have been published on this topic. We try to review these results in order to give indications for their correct use when calculating the attenuation laws for this area. Sun, 31 Mar 2013 22:00:00 GMT http://hdl.handle.net/2122/8559 2013-03-31T22:00:00Z http://hdl.handle.net/2122/8552 Title: Coseismic deformation and source modeling of the May 2012 Emilia (Northern Italy) earthquakes Authors: Pezzo, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Merryman Boncori, J. P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Tolomei, C.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Salvi, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Atzori, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Antonioli, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Trasatti, E.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Novali, F.; Tele-Rilevamento Europa - T.R.E. srl; Serpelloni, E.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia; Candela, L.; Agenzia Spaziale Italiana, Unità Osservazione della Terra; Giuliani, R.; Dipartimento della Protezione Civile, Ufficio Rischio Sismico Abstract: On May 20th, 2012, an ML 5.9 earthquake (Table 1) occurred near the town of Finale Emilia, in the Central Po Plain, Northern Italy (Figure 1). The mainshock caused 7 casualties and the collapse of several historical buildings and industrial sheds. The earthquake sequence continued with diminishing aftershock magnitudes until May 29th, when an ML 5.8 earthquake occurred near the town of Mirandola, ~12 km WSW of the mainshock (Scognamiglio et al., 2012). This second mainshock started a new aftershock sequence in this area, and increased structural damage and collapses, causing 19 more casualties and increasing to 15.000 the number of evacuees. Shortly after the first mainshock, the Department of Civil Protection (DPC) activated the Italian Space Agency (ASI), which provided post-seismic SAR Interferometry data coverage with all 4 COSMO-SkyMed SAR satellites. Within the next two weeks, several SAR Interferometry (InSAR) image pairs were processed by the INGV-SIGRIS system (Salvi et al., 2012), to generate displacement maps and preliminary source models for the emergency management. These results included continuous GPS site displacement data, from private and public sources, located in and around the epicentral area. In this paper we present the results of the geodetic data modeling, identifying two main fault planes for the Emilia seismic sequence and computing the corresponding slip distributions. We discuss the implication of this seismic sequence on the activity of the frontal part of the Northern Apennine accretionary wedge by comparing the co-seismic data with the long term (geological) and present day (GPS) velocity fields. Mon, 31 Dec 2012 23:00:00 GMT http://hdl.handle.net/2122/8552 2012-12-31T23:00:00Z