The joint probability distribution of different intensity measures (Formula presented.) at different sites in one earthquake is needed to define the stochastic process regulating the exceedance (in time) of the (Formula presented.) at the ensemble of the sites, which in turn is a funding element of the so-called multi-site probabilistic seismic hazard analysis (MSPSHA). The simplest model for the joint distribution of the (Formula presented.) in one seismic event requires the mean vector and the covariance matrix of the (Formula presented.) at all sites, conditional to the magnitude and location of the earthquake, which may need a large amount of data to be calibrated. The conditional hazard (CH) approach, originally developed for single-site surrogate vector-valued probabilistic seismic hazard analysis, may be a simplified option for MSPSHA, as it explicitly models only part of the covariance matrix of the (Formula presented.) at the sites, while the rest forcefully follows the working assumptions. The presented paper compares the CH approach for MSPSHA against the benchmark in which the complete covariance matrix is modelled, using a testbed in which one-hundred sites are considered. When the comparison metric is the probability of a given number of (Formula presented.) exceedances observed at the sites in some time intervals, it is found that CH is a viable alternative to MSPSHA, although the degree of approximation is sensitive to which and how many (Formula presented.) are considered (e.g., which spectral acceleration). When the analysis is taken all the way to the risk, considering the fragilities of a portfolio of hypothetical buildings, and taking as the metric the probability of observing a given number of structural failures in a time interval, it is found that the approximation introduced by CH with respect to the benchmark is further reduced.

Conditional hazard for simplified multi-site seismic hazard and risk analyses / Cito, P.; Chioccarelli, E.; Iervolino, I.. - In: EARTHQUAKE ENGINEERING & STRUCTURAL DYNAMICS. - ISSN 0098-8847. - 52:2(2023), pp. 482-499. [10.1002/eqe.3769]

Conditional hazard for simplified multi-site seismic hazard and risk analyses

Cito P.;Chioccarelli E.;Iervolino I.
2023

Abstract

The joint probability distribution of different intensity measures (Formula presented.) at different sites in one earthquake is needed to define the stochastic process regulating the exceedance (in time) of the (Formula presented.) at the ensemble of the sites, which in turn is a funding element of the so-called multi-site probabilistic seismic hazard analysis (MSPSHA). The simplest model for the joint distribution of the (Formula presented.) in one seismic event requires the mean vector and the covariance matrix of the (Formula presented.) at all sites, conditional to the magnitude and location of the earthquake, which may need a large amount of data to be calibrated. The conditional hazard (CH) approach, originally developed for single-site surrogate vector-valued probabilistic seismic hazard analysis, may be a simplified option for MSPSHA, as it explicitly models only part of the covariance matrix of the (Formula presented.) at the sites, while the rest forcefully follows the working assumptions. The presented paper compares the CH approach for MSPSHA against the benchmark in which the complete covariance matrix is modelled, using a testbed in which one-hundred sites are considered. When the comparison metric is the probability of a given number of (Formula presented.) exceedances observed at the sites in some time intervals, it is found that CH is a viable alternative to MSPSHA, although the degree of approximation is sensitive to which and how many (Formula presented.) are considered (e.g., which spectral acceleration). When the analysis is taken all the way to the risk, considering the fragilities of a portfolio of hypothetical buildings, and taking as the metric the probability of observing a given number of structural failures in a time interval, it is found that the approximation introduced by CH with respect to the benchmark is further reduced.
2023
Conditional hazard for simplified multi-site seismic hazard and risk analyses / Cito, P.; Chioccarelli, E.; Iervolino, I.. - In: EARTHQUAKE ENGINEERING & STRUCTURAL DYNAMICS. - ISSN 0098-8847. - 52:2(2023), pp. 482-499. [10.1002/eqe.3769]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11588/906337
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