UCI-UniNa joint research on engineering validation of ground motion simulations for past events

The Southern California Earthquake Center (SCEC) has established a Technical Activity Group (TAG) focused on Ground Motion Simulation Validation (GMSV) in order to develop and implement testing/rating methodologies via collaboration between ground motion modelers and engineering users. Within the GSMV TAG, a collaborative research started in February 2011 between the University of California Irvine (UCI) and the University of Naples Federico II, Italy (UniNa) to validate simulated ground motions for past earthquakes using engineering demand metrics, i.e., elastic and inelastic response spectra and generalized interstory drift and floor accelerations spectra. In the present paper, we summarize the results of the first phase of this ongoing study. In particular, the aim is to address, on a statistical basis, whether simulated GMs for four historical earthquakes are biased in terms of their median linear and nonlinear response characteristics in comparison with real records. We also look into dispersion (i.e., intra-event variability) of response to recorded and simulated GMs. Hypothesis tests on selected samples are also carried out to assess the statistical significance of the result found in terms of both peak and, in the case of nonlinear systems, cyclic response.