Stochastic ground motion simulations for seismic hazard assessment in the urban area of Xemxjia, Malta

This paper aims to provide earthquake ground motion simulations in order to estimate earthquake scenarios mainly based on the ground motion parameters. The Xemxija Bay area, located on the north-east coast of the island of Malta, was selected as a test site for a number of reasons. The area is characterised by complex geology and topography that varies over a small spatial scale, it also represents a site of particular historical interest, and it has important role as a touristic urban area. Building are located in a diversity of topographical settings, such as slopes, ridges and valleys and a variety of building types and ages can be identified. The expected ground motion parameters in terms of peak ground acceleration (PGA), peak ground velocity (PGV), and Spectral Acceleration (SA) as a function of distance and magnitude, were predicted using the latest version of EXSIM program (Boore, 2010). Three potential faults, one located on the Hyblean-Malta Escarpment, one at about 20 km south of Malta, and one at about 30 km east of Malta, were selected. despite certain uncertainties mostly due to source complexi¬ty, stochastic finite-fault modeling based on a dynamic frequency approach proves to be a reliable and practical method to simulate ground motion records of moderate and large earthquakes espe¬cially in regions where structural damage is expected but sparse ground motion recordings are avail¬able. In this paper, we show that in the Xemxija Bay area, Malta, the ground motion from the repeat occurrence of historically recorded earthquakes, coupled with existing geological conditions and building typologies has the potential to cause significant structural damage in the area.