Recalibration of the Intensity Prediction Equation in Italy Using the Macroseismic Dataset DBMI15 Version 2.0

Abstract

Abstract We recompute the coefficients of the intensity prediction equation (IPE) in Italy using the data of the DBMI15 version 2.0 (v.2.0) intensity database and the instrumental and combined (instrumental plus macroseismic) magnitudes reported by the CPTI15 v.2.0 catalog. We follow the same procedure described in the previous article, consisting of a first step in which the attenuation of intensity I with respect to the distance D from macroseismic hypocenter is referred to the expected intensity at the epicenter IE and a second step in which IE is related to the instrumental magnitude Mi, the combined magnitude Mc, the epicentral intensity I0, and the maximum intensity Imax using error-in-variable (EIV) regression methods. The main methodological difference with respect to the original article concerns the estimation of the uncertainty of IE to be used for EIV regressions, which is empirically derived from the standard deviation of regression between IE and Mi and also used for the regressions of IE with Mc, I0, and Imax. In summary, the new IPE determined from DBMI15 v.2.0 is I=IE−0.0081(D−h)−1.072[ln(D)−ln(h)], in which D=R2+h2, h = 4.49 km, and IE can be calculated from the intensity data distribution of the earthquake. If the intensity data distribution is not available, IE can be calculated from the following relationships IE=−2.578+1.867Mw, IE=I0.