Application and Comparison of Tsunami Vulnerability and Damage Models for the Town of Siracusa, Sicily, Italy

Siracusa is one of the most important cities of the eastern coast of Sicily, which according to historical records and to the present knowledge of the tectonic setting, is exposed to tsunamis generated by landslides on the Malta escarpment and by local and remote (e.g., Eastern Hellenic Arc) earthquakes. For this reason, the area of Siracusa has been selected as one of the test sites to conduct specific studies within the European FP7 project ASTARTE. In this frame, this work focuses on the assessment of tsunami vulnerability of (and damage to) the building stock of the town. The analysis is carried out following two different models, namely the SCHEMA and the Papathoma Tsunami Vulnerability Assessment (PTVA-3) methods. Topographic and building stock data in the potentially flooded areas are taken from detailed digital databases produced by the region of Sicily, integrated with satellite and photographic imagery from Google Earth and further validated by field surveys. We have explored three inundation scenarios corresponding to a constant-level tsunami flooding with assumed sea level rise of 1, 3 and 5 m, and evaluated the damage to the town buildings using both methods that make use of a 5-degree scale. The main result is that the level of damage of both models is not consistent, and that consistency may be improved if one changes from a 5- to a 3-degree damage scale.