Armagedom — A Tool for Seismic Risk Assessment Illustrated with Applications

Abstract

Over recent years, many studies devoted to large-scale seismic risk analyses have been carried out in different regions and by various research teams. A wide variety of software is available to perform these analyses: they are more or less flexible and use different levels of precision to model ground motion and vulnerability of the built environment. All are based on risk calculation through the convolution of hazard and vulnerability. This article presents a seismic risk analysis tool, Armagedom, implemented over the past five years on a variety of urban seismic contexts: Bouzareah (Algeria), four provinces in Iran, the French Departments lying along the French/Spanish border, and Overseas Departments in the French Antilles. The objectives and requirements of these studies differed with respect to the level of precision that was sought and the surface areas examined. In order to meet differing project targets, three levels of seismic risk assessment were defined based on the macroseismic and mechanical approaches for vulnerability and damage estimation presenting different levels of precision: Level N0 estimates seismic risk on a regional territorial scale based on the macroseismic approach and existing statistical data; Level N1 yields the seismic risk at a district level based on the macroseismic approach and on visual evaluation of the vulnerability of structures over an itinerary in the area to be analyzed; and Level N2 also establishes the seismic risk at a district level, but the hazard description is represented by a spectrum and vulnerability is estimated based on mechanical models. The software, with a modular design, was developed in order to optimize computation time and automate execution of the three levels of analysis. In this article, the software modules are illustrated by maps derived from the seismic risk analyses performed. We further use the available event information to test, validate, and update the methods and software presented in this article.