Seismic Hazard Assessment (2003–2009) for the Italian Building Code
01 Aug 2011-Bulletin of the Seismological Society of America (GeoScienceWorld)-Vol. 101, Iss: 4, pp 1885-1911
TL;DR: In this paper, a probabilistic assessment of seismic hazard (PSHA) of Italy in view of the building codes from 2003 to 2009 is presented, based on a logic-tree approach.
Abstract: This paper describes the probabilistic assessment of seismic hazard (PSHA) of Italy in view of the building codes from 2003 to 2009. A code was issued in 2003 as a Prime Minister Ordinance, requiring that a PSHA for updating the seismic zoning would be performed in one year, in terms of horizontal peak ground acceleration (PGA) with 10% probability of exceedance in 50 years on hard ground. For the first time in Italy, a working group, established by the Istituto Nazionale di Geofisica e Vulcanologia, adopted a logic-tree approach to model the epistemic uncertainty in the completeness of the earthquake catalog, the assessment of the seismicity rates and M max, and the ground-motion prediction equations. The seismic hazard has been computed over a grid of more than 16,000 points for the median value (fiftieth percentile) and the eighty-fourth and sixteenth percentiles of the 16 branches of the logic tree. Using the same input model, PGA values and spectral accelerations for 10 spectral periods were computed for nine different probabilities of exceedance in 50 years. This wealth of data made it possible to base the design spectra of a new building code on point hazard data instead of being related to just four zones. The 2009 M w 6.3 L’Aquila earthquake has led many to attempt to test the reliability of this study. In this paper, we analyze suggestions coming from that event and conclude that significant changes to the design spectra are not to be recommended based just on evidence from the L’Aquila earthquake.
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TL;DR: The 2013 European Seismic Hazard Model (ESHM13) as discussed by the authors is a consistent seismic hazard model for Europe and Turkey which overcomes the limitation of national borders and includes a through quantification of the uncertainties.
Abstract: The 2013 European Seismic Hazard Model (ESHM13) results from a community-based probabilistic seismic hazard assessment supported by the EU-FP7 project “Seismic Hazard Harmonization in Europe” (SHARE, 2009–2013). The ESHM13 is a consistent seismic hazard model for Europe and Turkey which overcomes the limitation of national borders and includes a through quantification of the uncertainties. It is the first completed regional effort contributing to the “Global Earthquake Model” initiative. It might serve as a reference model for various applications, from earthquake preparedness to earthquake risk mitigation strategies, including the update of the European seismic regulations for building design (Eurocode 8), and thus it is useful for future safety assessment and improvement of private and public buildings. Although its results constitute a reference for Europe, they do not replace the existing national design regulations that are in place for seismic design and construction of buildings. The ESHM13 represents a significant improvement compared to previous efforts as it is based on (1) the compilation of updated and harmonised versions of the databases required for probabilistic seismic hazard assessment, (2) the adoption of standard procedures and robust methods, especially for expert elicitation and consensus building among hundreds of European experts, (3) the multi-disciplinary input from all branches of earthquake science and engineering, (4) the direct involvement of the CEN/TC250/SC8 committee in defining output specifications relevant for Eurocode 8 and (5) the accounting for epistemic uncertainties of model components and hazard results. Furthermore, enormous effort was devoted to transparently document and ensure open availability of all data, results and methods through the European Facility for Earthquake Hazard and Risk (
www.efehr.org
).
399 citations
Cites background or result from "Seismic Hazard Assessment (2003–200..."
...In contrast, for ITAS308 the difference between the estimates taken from the current Italian Seismic Hazard Model (a = 4.2, b = 1; Stucchi et al. 2011) and the PML (apml = 3....
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...In contrast, for ITAS308 the difference between the estimates taken from the current Italian Seismic Hazard Model (a = 4.2, b = 1; Stucchi et al. 2011) and the PML (apml = 3.92, bpml = 0.98) is negligible....
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...…however, are traditionally based on similar yet different procedures that are not harmonised and can result in considerable differences at country borders (e.g. Grünthal et al. 1998; Grünthal and Wahlström 2000; Wiemer et al. 2009b; Stucchi et al. 2011; Dominique and Andre 2012; Musson 2012)....
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...National models or those covering several countries, however, are traditionally based on similar yet different procedures that are not harmonised and can result in considerable differences at country borders (e.g. Grünthal et al. 1998; Grünthal and Wahlström 2000; Wiemer et al. 2009b; Stucchi et al. 2011; Dominique and Andre 2012; Musson 2012)....
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National Institute of Geophysics and Volcanology1, Boğaziçi University2, University of Bologna3, National and Kapodistrian University of Athens4, British Geological Survey5, Institut de radioprotection et de sûreté nucléaire6, NORSAR7, Central Institution for Meteorology and Geodynamics8, Instituto Geográfico Nacional9, University of Lisbon10, Russian Academy of Sciences11
TL;DR: The SHARE European Earthquake Catalogue (SHEEC), which covers the time window 1000–1899, is described and a strategy focussed on maximizing the homogeneity of the final epicentral location and Mw, has been adopted.
Abstract: In the frame of the European Commission project “Seismic Hazard Harmonization in Europe” (SHARE), aiming at harmonizing seismic hazard at a European scale, the compilation of a homogeneous, European parametric earthquake catalogue was planned. The goal was to be achieved by considering the most updated historical dataset and assessing homogenous magnitudes, with support from several institutions. This paper describes the SHARE European Earthquake Catalogue (SHEEC), which covers the time window 1000–1899. It strongly relies on the experience of the European Commission project “Network of Research Infrastructures for European Seismology” (NERIES), a module of which was dedicated to create the European “Archive of Historical Earthquake Data” (AHEAD) and to establish methodologies to homogenously derive earthquake parameters from macroseismic data. AHEAD has supplied the final earthquake list, obtained after sorting duplications out and eliminating many fake events; in addition, it supplied the most updated historical dataset. Macroseismic data points (MDPs) provided by AHEAD have been processed with updated, repeatable procedures, regionally calibrated against a set of recent, instrumental earthquakes, to obtain earthquake parameters. From the same data, a set of epicentral intensity-to-magnitude relations has been derived, with the aim of providing another set of homogeneous Mw estimates. Then, a strategy focussed on maximizing the homogeneity of the final epicentral location and Mw, has been adopted. Special care has been devoted also to supply location and Mw uncertainty. The paper focuses on the procedure adopted for the compilation of SHEEC and briefly comments on the achieved results.
287 citations
Cites methods from "Seismic Hazard Assessment (2003–200..."
...An alternative approach is the so-called “historical” one (see for instance Stucchi et al. 2004, 2011)....
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TL;DR: In this paper, the authors examined the structural vulnerability of one-story precast concrete structures not designed and detailed for seismic loads and found that the structural displacement demand of the industrial buildings under consideration is larger than traditional RC frame structures owing to their higher flexibility, according to both higher interstory height and to a cantilevered static scheme.
Abstract: Recent major earthquakes in the Italian territory have reaffirmed the seismic vulnerability of precast industrial buildings typical of past Italian building practices, highlighting structural deficiencies observed during previous events and primarily related to the transfer of horizontal forces between structural and nonstructural elements. An intrinsic lack of shear and ductility capacity has been observed in simply supported beam-to-joist and beam-to-column connections, primarily constituted by vertical steel dowels or solely relying on shear friction, with or without neoprene pads. These connections were designed neglecting seismic loads and their premature failure was observed during recent seismic events to cause a loss of support of beam elements, owing to the relative movements of elements, and the collapse of part of the buildings, primarily the roof. The seismic displacement demand of the industrial buildings under consideration is larger than traditional RC frame structures owing to their higher flexibility, according to both higher interstory height and to a cantilevered static scheme. Furthermore, this high flexibility may also result in displacement incompatibility between structural and nonstructural elements, such as precast cladding panels, causing their connection failure. On the basis of detailed field observations on a relevant number of buildings, collected just after the earthquakes, seven representative industrial facilities are examined to outline the primary vulnerabilities of one-story precast concrete structures not designed and detailed for seismic loads.
188 citations
Cites background from "Seismic Hazard Assessment (2003–200..."
...…in 50 years around 0.125 – 0.15g and of about 0.250 – 0.275g for a 2% probability of exceedance in the same time interval (Gruppo di Lavoro 2004; Stucchi et al. 2011); following disaggregation analysis (see 6 http://esse1.mi.ingv.it/, last accessed October 2013), the largest contribution to…...
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...The area source 912 is considered capable to generate earthquakes as large as 6.14 MW (Gruppo di Lavoro 2004; Stucchi et al. 2011) in line with the characteristics and location of the two main earthquakes of 2012, occurred on May, 20th (6.11 MW according to the European and Mediterranean Regional…...
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...Meletti et al. (2013) performed a comparison between the hazard results of Stucchi et al. (2011) and strong-motion data produced by the sequence of earthquakes occurred in 2012....
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...275g for a 2% probability of exceedance in the same time interval (Gruppo di Lavoro 2004; Stucchi et al. 2011); following disaggregation analysis (see...
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...This observation roughly matches the recurrence interval defined by Stucchi et al. (2011) for the largest events generated by the area source encompassing the 2012 sequence....
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TL;DR: In this paper, the authors invert waveforms from 26 three-component strong motion accelerometers, filtered between 0.02 and 0.5 Hz, within 45 km from the fault.
Abstract: On 24 August 2016 a magnitude ML 6.0 occurred in the Central Apennines (Italy) between Amatrice and Norcia causing nearly 300 fatalities. The main shock ruptured a NNW-SSE striking, WSW dipping normal fault. We invert waveforms from 26 three-component strong motion accelerometers, filtered between 0.02 and 0.5 Hz, within 45 km from the fault. The inferred slip distribution is heterogeneous and characterized by two shallow slip patches updip and NW from the hypocenter, respectively. The rupture history shows bilateral propagation and a relatively high rupture velocity (3.1 km/s). The imaged rupture history produced evident directivity effects both N-NW and SE of the hypocenter, explaining near-source peak ground motions. Fault dimensions and peak slip values are large for a moderate-magnitude earthquake. The retrieved rupture model fits the recorded ground velocities up to 1 Hz, corroborating the effects of rupture directivity and slip heterogeneity on ground shaking and damage pattern.
163 citations
TL;DR: The last National Risk Assessment NRA for Italy was developed at the end of 2018 by the Department of Civil Protection (DPC) in response to the specific requirement of the Sendai Framework for Disaster Risk Reduction 2015-2030 to periodically adjourn the assessment of disaster risk as mentioned in this paper.
Abstract: The last National Risk Assessment NRA for Italy was developed at the end of 2018 by the Department of Civil Protection (DPC) in response to the specific requirement of the Sendai Framework for Disaster Risk Reduction 2015–2030 to periodically adjourn the assessment of disaster risk. The methodology adopted to perform seismic risk assessment and build national seismic risk maps was specifically developed to comply with the recent Code for Civil Protection, issuing that, in addition to a solid scientific base, risk assessment should be characterized by a wide consensus of the scientific community. As a result, six research units belonging to two Centers of Competence of the DPC, namely ReLUIS (Network of university laboratories for seismic engineering) and EUCENTRE (European Centre for Training and Research in Earthquake Engineering), collaborated under the guidance and coordination of DPC to produce the recent updating of national seismic risk maps for the residential building stock. This paper describes the methodology adopted to develop the consensus-based national seismic risk assessment and presents the main results in terms of expected damage and impact measures (unusable buildings, homeless, casualties, direct economic losses).
127 citations
References
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TL;DR: In this article, a statistical comparison of earthquake frequency in California with that of the world as a whole was made by comparing the historical record of the earthquake frequency of California with the global average.
Abstract: Estimates of the frequency of destructive shocks in California have usually been
based on the very imperfect historical record. The present note attempts to revise
these estimates by statistical comparison of earthquake frequency in California
with that of the world as a whole.
3,396 citations
TL;DR: In this article, the authors developed modifications to empirical strong ground motion attenuation relations to account for the effects of rupture directivity on strong motion amplitudes and durations, based on an empirical analysis of near-fault data.
Abstract: Rupture directivity effects cause spatial variations in ground motion amplitude and duration around faults and cause differences between the strike-normal and strike-parallel components of horizontal ground motion amplitudes, which also have spatial variation around the fault. These variations become significant at a period of 0.6 second and generally grow in size with increasing period. We have developed modifications to empirical strong ground motion attenuation relations to account for the effects of rupture directivity on strong motion amplitudes and durations. The modifications are based on an empirical analysis of near-fault data. The ground motion parameters that are modified include the average horizontal response spectral acceleration, the duration of the acceleration time history, and the ratio of strike-normal to strike-parallel spectral acceleration. The parameters upon which the adjustments to average horizontal amplitude and duration depend are the fraction of the fault rupture that occurs on the part of the fault that lies between the hypocenter and the site, and the angle between the fault plane and the path from the hypocenter to the site. Since both of these parameters can be derived from the hypocenter location and the fault geometry, the model of rupture directivity effects on ground motions that we have developed can be directly included in probabilistic seismic hazard calculations. The spectral acceleration is larger for periods longer than 0.6 second, and the duration is smaller, when rupture propagates toward a site. For sites located close to faults, the strike-normal spectral acceleration is larger than the strike-parallel spectral acceleration at periods longer than 0.6 second in a manner that depends on magnitude, distance, and angle. To facilitate the selection of time histories that represent near-fault ground motion conditions in an appropriate manner, we provide a list of near-fault records indicating the rupture directivity parameters that each contains.
1,219 citations
01 Jan 1981
TL;DR: In this paper, a magnitude-independent shape based on geometrical spreading and anelastic attenuation was proposed for the attenuation curve, which decouples the determination of the distance dependence of the data from the magnitude dependence.
Abstract: We have taken advantage of the recent increase in strong-motion data at close distances to derive new attenuation relations for peak horizontal acceleration and velocity. This new analysis uses a magnitude-independent shape, based on geometrical spreading and anelastic attenuation, for the attenuation curve. An innovation in technique is introduced that decouples the determination of the distance dependence of the data from the magnitude dependence. The resulting equations are log A = − 1.02 + 0.249 M − log r − 0.00255 r + 0.26 P r = ( d 2 + 7.3 2 ) 1 / 2 5.0 ≦ M ≦ 7.7 log V = − 0.67 + 0.489 M − log r − 0.00256 r + 0.17 S + 0.22 P r = ( d 2 + 4.0 2 ) 1 / 2 5.3 ≦ M ≦ 7.4
where A is peak horizontal acceleration in g , V is peak horizontal velocity in cm/ sec, M is moment magnitude, d is the closest distance to the surface projection of the fault rupture in km, S takes on the value of zero at rock sites and one at soil sites, and P is zero for 50 percentile values and one for 84 percentile values.
We considered a magnitude-dependent shape, but we find no basis for it in the data; we have adopted the magnitude-independent shape because it requires fewer parameters.
1,020 citations
TL;DR: In this paper, a magnitude-independent shape based on geometrical spreading and anelastic attenuation was proposed for the attenuation curve, which decouples the determination of the distance dependence of the data from the magnitude dependence.
Abstract: We have taken advantage of the recent increase in strong-motion data at close distances to derive new attenuation relations for peak horizontal acceleration and velocity. This new analysis uses a magnitude-independent shape, based on geometrical spreading and anelastic attenuation, for the attenuation curve. An innovation in technique is introduced that decouples the determination of the distance dependence of the data from the magnitude dependence. The resulting equations are log A = − 1.02 + 0.249 M − log r − 0.00255 r + 0.26 P r = ( d 2 + 7.3 2 ) 1 / 2 5.0 ≦ M ≦ 7.7 log V = − 0.67 + 0.489 M − log r − 0.00256 r + 0.17 S + 0.22 P r = ( d 2 + 4.0 2 ) 1 / 2 5.3 ≦ M ≦ 7.4
where A is peak horizontal acceleration in g , V is peak horizontal velocity in cm/ sec, M is moment magnitude, d is the closest distance to the surface projection of the fault rupture in km, S takes on the value of zero at rock sites and one at soil sites, and P is zero for 50 percentile values and one for 84 percentile values.
We considered a magnitude-dependent shape, but we find no basis for it in the data; we have adopted the magnitude-independent shape because it requires fewer parameters.
1,010 citations
TL;DR: In this paper, a large and uniform dataset is used to find equations for the prediction of absolute spectral acceleration ordinates in Europe and adjacent areas, in terms of magnitude, source-distance and site geology.
Abstract: A large and uniform dataset is used to find equations for the prediction of absolute spectral acceleration ordinates in Europe and adjacent areas, in terms of magnitude, source-distance and site geology. The dataset used is shown to be representative of European strong motion in terms of the attenuation of peak ground acceleration. The equations are recommended for use in the range of magnitudes from M s 4.0 to 7.5 and for source-distances of up to 200 km.
725 citations