The application of open-source software ANUGA installed on a BlueJ/Q computer for a tsunami modelling in costal areas of city of Trieste using high resolution laser-scanning and multibeam data

Paolo Sterzai

Abstract


Due to the characteristics of seismo-tectonic is an event of a tsunami in the northern Adriatic considered as unlikely. However many historical sources report that in 1512 a tsunami induced by an earthquake occurred devastating the city. The problems of the city in case of heavy rains about the coastal flooding is well known especially in the case of west - winds. This paper presents a dynamic hydraulic modeling of the city of Trieste in the event of a tsunami during a contemporary storm surge along the coastal areas using the open-source software ANUGA installed on a machine BlueJ/Q. The hydraulic modeling used for this purpose calculates the solutions from the fluid motion equation through the Navier-Stokes equations using some mathematical simplifications in the case of wave equations due to shallow water equations, as the fluid incompressibility, uniform vertical velocity distribution, uniform distribution of the hydrostatic pressure and a gentle slope of the seabed. A digital elevation model of the terrain has been used along the coast obtained by laser-scanning fused with a multibeam batimetry for the onshore data, with a final resolution of about 1 point per square meter. The data were corrected for the average height of the seas defined by the geoid ADBVE 2008. Due to the large amount of data using a high resolution digital terrain as well as batymetric model, the modelling computations have been done using the super-computer BlueJ/Q, which optimized the parallelization of the code. The hydraulic modeling high resolution required in urban areas which takes account of buildings, road structures, channels etc.. requires a computing capacity which is not possible to deal with PC seen the magnitude of the mesh used and the complexity considered to obtain reliable temporal evolution.
Considering occurrence of an event of a tsunami in correspondence to an event of a flood wave 2 meters due to storm surges, then the worst possible case, by entering into a GIS all simulations it was possible to outline the areas of highest risk, indicating the areas that would require surgery in order to prevent problems of civil protection. 


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