Inventory of uncertainties associated with the process of tsunami damage assessment on buildings (SCHEMA FP6 EC co-funded project)

Abstract. Within the framework of the SCHEMA FP6 EC co-funded project (http://www.schemaproject.org), we have identified the sources of errors/uncertainties that can be introduced at several steps of the damage assessment process, from post-disaster field measures up to hazard and damages maps production. Errors, for instance, are introduced when collecting post-disaster observations owing to different types of instruments/methods, water marks considered, tide correction, etc.: in extreme cases, differences of meters can be found between water heights data published by different teams for the same locations. Much uncertainty comes from difficulties in identifying and characterizing the potential tsunami sources and from numerical modelling. Moreover, the resolution of the employed Digital Terrain Models can noticeably affect the predicted inundation extent. We have also verified that the consistency of the computations on the long term varies sensitively depending on the code, raising the problem of results reliability for emergency management in dangerous coasts exposed to repeated waves. In addition, damage assessment is performed using damage functions linking the mean damage level on buildings with the maximum water elevation measured in the field without considering other tsunami parameters such as stream velocity. Finally, we examined uncertainties introduced in hazard and vulnerability mapping due to cartographic processing.