Simulating Earthquake Scenarios in the European Project LESSLOSS: The Case of Lisbon

Abstract

This paper is a completion of a previous paper published in the proceeding of the 1755 Lisbon Earthquake Conference and contain the results after the European Project LESSLOSS Risk Mitigation for Earthquakes and Landslides (Lessloss) regarding the evaluation of earthquake scenarios for the Metropolitan Area of Lisbon (MAL). In the framework of the subproject 10, SP10 Earthquake disaster scenario prediction and loss modelling, finite-fault seismological models have been proposed to compute the earthquake scenarios for three urban areas: Istanbul (Turkey), Lisbon (Portugal) and Thessaloniki (Greece). The overall aim of SP10 is to create a tool, based on state-of-the art modelling software, to provide strong quantified statements about the benefits and costs of a range of possible mitigation actions, to support decision-making by city and regional authorities for seismic risk mitigation strategies. First element of this analysis process is the definition of the input as hazard parameter (Fig. 1). The generation of earthquake ground motion scenarios involves both the particular choice of earthquake sources with associated fault rupture parameters, and the ensuing ground motion field calculated by an appropriate numerical tool, or empirically estimated, at a set of selected points within the urban area of interest. For SP10 the aim was to define ground shaking hazard associated with particular scenario events, defined as earthquakes with a given magnitude and location, taken to be the worst event which would take place with a given return period, 50, 100 or 500 years. Defining that earthquake requires a close study of the capable faults, of the earthquake recurrence on those faults, and may also require a de-aggregation analysis of the local effects from all faults capable of generating damaging ground motions.