Abstract:
Significant tsunamis in Northern Adriatic are extremely rare and only a few historical
events were reported in the literature, with possible sources mostly located along with
central and southern parts of the Adriatic coasts. Recently, an alert tsunami system has
been established for the whole Mediterranean area, including the Adriatic Sea.
However, a detailed description of the potential impact of such waves on coastal areas,
particularly urban ones, is still missing.
The scope of this thesis is to model the hazard associated with possible tsunamis,
generated by relatively distant earthquakes (i.e., with epicentres located at few hundred
kilometres distance, and arrival times of hours), for urban areas located along the
Northern Adriatic coasts. Tsunami modelling is performed by the NamiDance software,
which allows accounting for seismic source properties, variable bathymetry, and nonlinear
effects in waves propagation. Urban scale hazard scenarios for selected cities
are developed considering different potential tsunamigenic sources of tectonic origin,
located in the Central and Southern Adriatic Sea. Sources are defined according to
available literature, which includes catalogues of a historical tsunami and existing largescale
models. Information about the morphology of the study areas (i.e., bathymetry,
topography) available at OGS is used, along with additional data retrieved online and
from literature.
A set of tsunami scenarios is modelled, considering possible sources related to
historical events, as well as extremely large events not yet observed; parametric tests
are performed, for increasing scenario earthquakes magnitudes (i.e. source size), to
account for seismic source variability. Preliminary tsunami hazard estimates, which
may allow developing inundation scenarios, are computed for selected cities, namely
Trieste, Monfalcone, Lignano and Grado, depending on data availability and on the
relevance of the site. Accordingly, a preliminary set of tsunami-related parameters and
maps are obtained, including maximum runup at the selected sites; arrival time of the
first wave along the coast; time series of water level fluctuations at selected locations
(mareograms); tsunami propagation maps; distributions of the arrival time of the
maximum swell along the coast.
