Assessing the tsunami risk from submarine landslides on the Maltese islands

Abstract

Since the 2004 Indian Ocean tsunami disaster, many studies have been conducted to predict tsunami occurrences based on previous tsunami events. Very little has been done with regards to the Maltese Islands. Most studies conducted always look at tsunamigenic earthquakes. However, not all tsunami events have occurred due to seismic activities. In this study, four possible tsunamigenic submarine landslides: the Gela Twin slides, the Malta Escarpment (ME) slide and the mass transport deposit (MTD) SL6, located at the central and eastern margins of the Mediterranean Sea, were analysed to see whether their voluminous mass could trigger a tsunami. They were first analysed through the use of a Geographic Information Software (GIS). This software helped identify their exact location as well as measure their run-out distance together with the width and area of slide. This gathered information was then used to create a 2-D tsunami model using the Australian National University and Geoscience Australia (ANUGA) Open Source Hydrodynamic/Hydraulic Modelling Project. The model was tested on the default scenario (Cairns, Australia) set by ANUGA and the results were then applied for the Maltese Islands' coastline. The Cairns bathymetry is very similar to that of Malta, with areas ranging from 5-400m in depth at the continental shelf. Results show that of all the slide scenarios, the ME slide scenario is the most similar to the real setting, whilst that of the MTD SL6 is the most dissimilar. Further research has to be conducted in order to predict tsunami occurrence and minimise risk hazard at high risk zones.