Sources and scenarios for tsunami hazard assessment in the Mediterranean

A very preliminary view

Tsunami Hazard Assessment

• 1. Deterministic (usually“credible” worst tsunami, Tinti and Armigliato, 2003)• 2. Scenario-based assessment• 3. Probabilistic (P for the exceedance of height H in T years,

e.g. Sørensen et al., 2012) /statistics (size-frequency relations)

All (!) approaches suffer due to • 1. Poor knowledge of mechanisms• 2. Are realistic (?)• 3. Very small ts. catalogs (simulations/synthetic catalogs is

an alternative)

Geotectonic setting(Mascle & Mascle, 2012)

Tsunamigenic zones(Papadopoulos et al., Mar. Geol., 2014)

Rupture zones of tsunamigenic earthquakes(Papadopoulos & Papageorgiou, Cambridge Univ. Press, 2014)

Rupture zones of tsunamigenic earthquakes(Papadopoulos & Papageorgiou, Cambridge Univ. Press, 2014)

Seismic criterion for the source: slowness factor(Newman and Okal , 1998)

Earthquake Seismic moment Mo x 1027 (dyn.cm)

Slowness factor, θ

Nicaragua 1992 7.66 3.40 -6.51Java 1994 7.87 5.30 -5.76Peru 1996 7.18 2.20 -6.22Flores Sea 1992 8.07 5.10 -4.58PNG 1998 6.80 0.37 -5.50Messina 1908 7.10 0.56 -5.39Amorgos 1956 7.50 3.90 -4.68

10

0

logE

M

Western Mediterranean: Álvarez-Gómez et al. (2011a) selected various worst case

seismogenic faults

Western Mediterranean: Álvarez-Gómez et al. (2011a) selected various worst case

seismogenic faults and calculated maximum wave elevation maps and tsunami travel times

Western Mediterranean: Iglesias et al. (2012) presented a reasonable present-day, sea-level highstand

numerical simulation and scenario for a tsunami excited by a hypothetical landslide with the characteristics of the pre-historic BIG’95 debris flow occurring on the Ebro

margin about 11500 cal yr BP

Strategies for developing database of pre-simulated tsunami scenarios

1. Discretization of a given “tsunamigenic domain” with sources distributed on a regular grid of cells, independently on the tsunami history. Tsunami scenarios are computed for each grid cell and for different EQ magnitudes starting from “standard” tsunami initial conditions (practice by Global Disasters Alerts & Coordination System, JRC, Ulutas et al., 2012).

2. The second approach applies when sound hypotheses on tectonic lineaments and/or specific active and potentially tsunamigenic faults can be made: “source-based” approach: the fault areas are tessellated with elementary faults of suitable extension and with focal mechanism coinciding with that of the parent source area. (e.g adopted by the NOAA Tsunami Research Center “Short-Term Inundation Forecast” (SIFT) operational tool).

NEARTOWARN Project: “source-based” approach applied by UNIBO

Cyprus Rhodes