Integrating macroseismic intensity distributions with a probabilistic approach: an application in Italy

Andrea Antonucci,Vera D'Amico,Andrea Rovida,Dario Albarello

doi:10.5194/nhess-21-2299-2021

Abstract

Abstract. The geographic distribution of earthquake effects quantified in terms of macroseismic intensities, the so-called macroseismic field, provides basic information for several applications including source characterization of pre-instrumental earthquakes and risk analysis. Macroseismic fields of past earthquakes as inferred from historical documentation may present spatial gaps, due to the incompleteness of the available information. We present a probabilistic approach aimed at integrating incomplete intensity distributions by considering the Bayesian combination of estimates provided by intensity prediction equations (IPEs) and data documented at nearby localities, accounting for the relevant uncertainties and the discrete and ordinal nature of intensity values. The performance of the proposed methodology is tested at 28 Italian localities with long and rich seismic histories and for two well-known strong earthquakes (i.e., 1980 southern Italy and 2009 central Italy events). A possible application of the approach is also illustrated relative to a 16th-century earthquake in the northern Apennines.

Highlights

Characterizing earthquake effects on the anthropic environment is of paramount importance for estimating seismic risks and planning prevention policies
Macroseismic intensity can be useful to check the outcomes of probabilistic seismic hazard assessments (Stirling and Petersen, 2006; Mucciarelli et al, 2008; Rey et al, 2018), especially in countries where the historical record is much longer than the instrumental one
To estimate the probability q(Iv|Is) in Eq (1), one can consider the relative frequencies of the differences between intensity values at pairs of sites affected by the same event

Summary

Introduction

Characterizing earthquake effects on the anthropic environment is of paramount importance for estimating seismic risks and planning prevention policies. The spatial distribution of IDPs is considered for the characterization of the earthquake source (i.e., estimates of epicentral location and magnitude) in the absence of instrumental data (e.g., Bakun and Wentworth, 1997; Gasperini et al, 1999, 2010; Provost and Scotti, 2020). Collecting these parameters in homogeneous seismic catalogues (e.g., Fäh et al, 2011; Stucchi et al, 2013; Manchuel et al, 2018; Rovida et al, 2019, 2020) is a key element to providing a seismic characterization of a region, and this information represents a basic tool for seismic hazard estimates (e.g., Stucchi et al, 2011; Woessner et al, 2015; Meletti et al, 2021). Macroseismic intensity can be useful to check the outcomes of probabilistic seismic hazard assessments (Stirling and Petersen, 2006; Mucciarelli et al, 2008; Rey et al, 2018), especially in countries where the historical record is much longer than the instrumental one

Methods

Results

Conclusion