Tsunami impact and vulnerability in the harbour area of Tangier, Morocco

Abstract

In this study, we assess tsunami impact and building vulnerability in the harbour area of Tangier – Morocco. Tsunami impact is evaluated through performing high-resolution inundation modelling. To assess buildings tsunami vulnerability, we use a geographic information system (GIS) multi-criteria approach based upon weight and classification factors. The methodology includes various steps: (i) identification of the most hazardous earthquake tsunamigenic sources, (ii) computation of high-resolution digital elevation model, (iii) simulation of inundation, (iv) field survey to classify buildings and defence structures and (v) application of the GIS-based model to produce final vulnerability map. Results show the potential tsunami impact and vulnerability that Tangier coast might face due to the occurrence of a large tsunami event in the region. Inundation map indicates that a coastal area of over 4.5 km2 is prone to tsunami flood with flow depths ranging from 0.5 to more than 6 m. Vulnerability map highlights different levels of expected buildings vulnerability to tsunami impact, which vary from “very high” for single-storey structures, located in the city harbour and along the sandy beach, to “low” for multi-storeys RC structures. Both inundation and vulnerability maps have important implications for decision makers and land use planning aiming to mitigate tsunami hazard in the North East Atlantic region.