This work presents a methodology for comparing the results of probabilistic seismic hazard (PSH) studies with historical macroseismic observations. The methodology is applied to Central Italy, and, specifically, to the Abruzzi region. This region is selected as case study, given its seismicity and the availability of information on the existing building stock, provided by post-earthquake data collected after the L’Aquila (2009) seismic event. The adopted procedure considers the mean damage, i.e. the average damage annually expected on the existing building stock, as metric of the comparison. To this end, macroseismic observations are converted into mean damage values, by using the macroseismic method. On the other hand, peak ground acceleration (PGA) thresholds, for which seismic hazard estimates are available, are associated with mean damage values, by taking advantage of empirical fragility curves, representative of the seismic vulnerability of the existing building stock. The use of a logic tree approach allows to take into account different sources of uncertainty, such as the uncertainty in the subdivision of the building stock into predefined building typologies and the uncertainty in the attribution of the different structural typologies to the vulnerability classes of the European macroseismic scale. The comparison between seismic hazard estimates and macroseismic observations is carried out on individual sites, in terms of annual rate of exceedance of predetermined mean damage thresholds.
Questo lavoro presenta una metodologia per il confronto tra i risultati delle analisi probabilistiche di pericolosità sismica e le osservazioni macrosismiche storiche applicata al Centro Italia, e nello specifico alla regione Abruzzo. Tale regione è stata scelta come caso studio, data la sua sismicità e la disponibilità di informazioni sul costruito esistente, fornite da dati post-terremoto de L’Aquila (2009). La procedura utilizzata considera, come metrica del confronto, il danno medio atteso sul costruito esistente. A tal fine, le osservazioni macrosismiche sono convertite in valori di danno medio, utilizzando il metodo macrosismico. Dall’altro lato, le soglie di accelerazione di picco al suolo (PGA), per le quali sono disponibili le stime di pericolosità, sono associate a valori di danno medio, utilizzando curve di fragilità empiriche, rappresentative della vulnerabilità sismica del costruito esistente. L’utilizzo di un approccio ad albero logico consente di tener conto di diverse fonti di incertezza, quali l’incertezza nella suddivisione del costruito nelle tipologie edilizie e nell’attribuzione delle diverse tipologie strutturali alle classi di vulnerabilità della scala macrosismica europea. Il confronto tra stime di pericolosità sismica e osservazioni macrosismiche è effettuato su singoli siti, in termini di tasso annuo di superamento di soglie di danno medio prefissate.
Confronto tra risultati di pericolosità sismica e osservazioni macrosismiche storiche nella regione Abruzzo
ANTONACI, ALESSIA
2018/2019
Abstract
This work presents a methodology for comparing the results of probabilistic seismic hazard (PSH) studies with historical macroseismic observations. The methodology is applied to Central Italy, and, specifically, to the Abruzzi region. This region is selected as case study, given its seismicity and the availability of information on the existing building stock, provided by post-earthquake data collected after the L’Aquila (2009) seismic event. The adopted procedure considers the mean damage, i.e. the average damage annually expected on the existing building stock, as metric of the comparison. To this end, macroseismic observations are converted into mean damage values, by using the macroseismic method. On the other hand, peak ground acceleration (PGA) thresholds, for which seismic hazard estimates are available, are associated with mean damage values, by taking advantage of empirical fragility curves, representative of the seismic vulnerability of the existing building stock. The use of a logic tree approach allows to take into account different sources of uncertainty, such as the uncertainty in the subdivision of the building stock into predefined building typologies and the uncertainty in the attribution of the different structural typologies to the vulnerability classes of the European macroseismic scale. The comparison between seismic hazard estimates and macroseismic observations is carried out on individual sites, in terms of annual rate of exceedance of predetermined mean damage thresholds.È consentito all'utente scaricare e condividere i documenti disponibili a testo pieno in UNITESI UNIPV nel rispetto della licenza Creative Commons del tipo CC BY NC ND.
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https://hdl.handle.net/20.500.14239/11547