Empirical vulnerability curves for Italian mansory buildings: evolution of vulnerability model from the DPM to curves as a function of accelertion

In the framework of the emergency management in the case of seismic events, the evaluation of the expected damage represents a basic requirement for risk informed planning. Seismic risk is defined by the probability to reach a level of damage on given exposed elements caused by seismic events occurring in a fixed period and in a fixed area. To this purpose, the expected seismic input, the exposed elements and their vulnerability have to be correctly evaluated. The aim of the research is to define a correct model of vulnerability curves, in PGA, for masonry structures in Italy, by heuristic approach starting from damage probability matrices (DPMs). To this purpose, the PLINIVS database, containing data on major Italian seismic events, has been used and supported by “critical” assumption on missing data. To support the reliability of this assumption, two vulnerability models, considering or not the hypothesis on the missing data, have been estimated and used to calculate the seismic scenario of the L’Aquila 2009 earthquake through the IRMA (Italian Risk MAp) platform. Finally, a comparison between the outcomes elaborated by IRMA platform and the observed damage collected in the AEDES forms, has been done.

Seismic vulnerability of vernacular Newari buildings in Nepal: observations and analysis of damage due to 1934, 1988, 2011, and 2015 earthquakes

This paper reports the seismic vulnerability of vernacular Newari buildings based on the damage observations during four major earthquakes (1934, 1988, 2011 and 2015) that struck Bhaktapur city. Some specific features that contributed to collapse prevention in traditional masonry buildings are also highlighted in this paper. In this paper, we have outlined the insights of each earthquake using forensic interpretations and the recommendations by various researchers after 1934 and 1988 earthquakes are compared in terms of their implementation. With the help of damage database recorded during 1934, 1988 and 2015 earthquakes, we have created damage probability matrices and empirical fragility functions for traditional masonry structures. The fragility functions and damage probability matrices derived in this study highlight that most of the vernacular Newari buildings are likely to be collapsed in the case of strong to major earthquakes.

A Beta Distribution Model for Characterizing Earthquake Damage State Distribution

This study investigates methods for modeling the distribution of post-earthquake damage among categorical damage states. Specifically, it is demonstrated that the beta distribution is a good model for characterizing the complete probability distribution of damage states conditioned on ground-motion intensity. Based on extensive post-earthquake damage surveys following the 2010 earthquake in Haiti, the paper proposes the method-of-moments and maximum likelihood estimate-based formulations to fit a beta distribution model to grouped categorical damage data. The beta distribution model is further compared with one based on the binomial distribution, often used to estimate damage state distribution. The study demonstrates that the beta distribution results in little bias and variance in predictions of damage and loss. This model can be the basis for developing damage probability matrices, fragility curves, post-disaster damage estimations, risk assessments, and more.