Evaluating connections between large boulders and potential tsunamis along the North Eastern coast of Malta

Abstract

This study tries to determine whether a connection exists between large boulders on the north-eastern coast of Malta and potential tsunamis. Considering Malta’s exposure to storm events, the boulders would have been transported to their current position by either storm or tsunami waves. The process of establishing whether this connection exists, consisted of the use of photogrammetry techniques together with hydrodynamic wave equations. Agisoft Methashape software enabled the use of photogrammetry in this dissertation. The advantages of using such a software are, that volume and dimensions of each boulder are more accurate and precise when compared to those calculated using conventional methods. The first two sets of equations were computed with the dimensions of each boulder whilst the second set of equation were computed with the volumes calculated by Agisoft and the conventional method (LxBxH). The results obtained from the hydrodynamic equations suggest, that storm waves might have been responsible for depositing these boulders on the coastal area. However, when tsunami wave heights were compared with those recorded for the 1693 and the 1908 tsunamis, which occurred along the eastern Sicilian coast, these suggest that the 1908 tsunami might have played a role in depositing these boulders. The probability that storm waves were responsible for transporting and depositing these boulders is more likely than the probability of tsunami waves doing so. The reason is the fact that the distances from the sea that were recorded and also Malta’s exposure to storm events all indicate the possibility that storm waves would have been responsible for the deposition of these boulders on the N.E coast of Malta.