GNGTS 2018 - 37° Convegno Nazionale

320 GNGTS 2018 S essione 2.1 PGMs. Hence, the following regression equations, determined using the mean values of the EMS98 classes, are obtained for PGV, PGA and PGD: = 4.21 0.09 + 1.64 0.06 · logPGV, σ = 0.362 (1) = 1.84 0.24 + 2.35 0.15 · logPGA, σ = 0.274 (2) = 5.87 0.21 + 1.62 0.15 · logPGD, σ = 0.289 (3) For each formulation, standard deviation values are given. The range of applicability of such Equations is derived according to the defined I EMS intensity bins, being between 2.5 and 8. Additionally, as a control tool, the same correlations are obtained considering the whole dataset, without any averaging: = 4.26 0.05 + 1.58 0.05 · logPGV, σ = 0.307 (4) = 2.10 0.11 + 2.21 0.08 · logPGA, σ = 0.245 (5) = 5.97 0.08 + 1.56 0.06 ·logPGD, σ = 0.273 (6) The range of applicability of Eqs. 4-6 is the one defined by the whole dataset, i.e. between 2 and 10. All the above formulations (Eqs. 4-6) are obtained with the ODR technique, thus this means that they represent fully-reversible ground motion-to-intensity conversion equations. As a control tool, data points were also used for regression analysis without any data binning and averaging procedure. Fig. 3 shows the resulting ground motion-to-intensity relations. Conclusions. This work presented new fully-invertible relations that correlate ground motion intensity measures and macroseismic intensity values expressed with EMS98 scale, which are developed starting from data collected for the Italian context, and a defined range of applicability. The importance of these formulations depends on the lack of any regression equation between peak ground motion (PGM) parameter and the most currently used EMS98 macroseismic intensity scale, which is one of the few that takes into account structural features of buildings, and thus accounts for their seismic vulnerability in the assignment of macroseismic intensity values. Such relationships can be considered, at the same time, both Intensity-to- Ground Motion Conversion Equations (IGMCEs) and Ground Motion-to-Intensity Conversion Equations (GMICEs), as they were developed through the Orthogonal Distance Regression technique. References Boggs, P.T., Spiegelman, C.H., Donaldson, J.R. and Schnabel, R.B., 1988. Acomputational examination of Orthogonal Distance Regression, Journal of Econometrics, 38, 169-201. Fig. 2 - Distribution of the observed EMS98 intensities with the distance from the nearest accelerometric station (NF = not felt).