Method Algeria Sources Southern Tyrrhenian Sea Sources Hellenic arc Sources

Fig.4

Fig.5

Fig.6

Fig.7

Fig.8

0 10 20 30

40

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

0.45

0.50

meters

10 15 35

40

0.025

0.050

0.075

0.100

0.125

0.150

0.175

0.200

0.225

0.250

meters

0 10 20 30

30

40

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

meters

distance (km)

0 200 400 600 800 1000 1200

0.1

0.2

0.3

0.4

0.5

0.6

0.7

distance (km)

wav

e h

eig

ht

(m) absolute maximum

standard deviation

average

0 200 400 600 800 1000 1200

0.2

0.4

0.6

0.8

distance (km)

wav

e h

eig

ht

(m)

absolute maximum

standard deviation

average

0 200 400 600 800 1000 1200

1

2

3

4

distance (km)

wav

e h

eig

ht

(m)

absolute maximum

standard deviation

average

0 50 100 150 2000.8

0.6

0.4

0.2

0

0.2

0.4

TRAPANI

time (minutes)

wav

e h

eig

ht

(m)

0 50 100 150 2000.8

0.6

0.4

0.2

0

0.2

0.4

NAPOLI

time (minutes)

wav

e h

eig

ht

(m)

0 50 100 150 2000.8

0.6

0.4

0.2

0

0.2

0.4

ORISTANO

time (minutes)

wav

e h

eig

ht

(m)

0 50 100 150 2000.8

0.6

0.4

0.2

0

0.2

0.4

CAGLIARI

time (minutes)

wav

e h

eig

ht

(m)

0 20 40 60 80 100 1200.2

0.15

0.1

0.05

0

0.05

0.1

0.15MESSINA

time (minutes)

wav

e h

eig

ht

(m)

0 20 40 60 80 100 1200.2

0.15

0.1

0.05

0

0.05

0.1

0.15PALERMO

time (minutes)

wav

e h

eig

ht

(m)

0 20 40 60 80 100 1200.2

0.15

0.1

0.05

0

0.05

0.1

0.15NAPOLI

time (minutes)

wav

e h

eig

ht

(m)

0 20 40 60 80 100 1200.2

0.15

0.1

0.05

0

0.05

0.1

0.15VIBO VALENTIA

time (minutes)

wav

e h

eig

ht

(m)

0 20 40 60 80 100 1200.2

0.15

0.1

0.05

0

0.05

0.1

0.15OROSEI

time (minutes)

wav

e h

eig

ht

(m)

0 50 100 150 200 250 300 350 4002

1.5

1

0.5

0

0.5

1

1.5

2SIRACUSA

time (minutes)

wav

e h

eig

ht

(m)

0 50 100 150 200 250 300 350 4002

1.5

1

0.5

0

0.5

1

1.5

2BARI

time (minutes)

wav

e h

eig

ht

(m)

0 50 100 150 200 250 300 350 4002

1.5

1

0.5

0

0.5

1

1.5

2CATANZARO

time (minutes)

wav

e h

eig

ht

(m)

Fig2. Mediterranean tsunamigenic sources setting.In blue are represented all the known seismogenic areas potentially capable of generating tsunamis in the Mediterranean area. Among these, three sample areas (in red) were chosen to illustrate the propagation and effects of the seismic-induced tsunami wave. The main tectonic features of the Mediterranean region are also represented. Hellenic ArcThis seismogenic source is historically proved to be capable of strong earthquakes (M=8) related to the subduction process active along the Hellenic trench system, responsible for the high level of seismicity in this area. We took the well constrained fault responsible for the 365 AD earthquake of Crete as the most representative tsunami sources in the area. Constraints came from coseismic displacement of shorelines in western Crete and Antikithira, reaching up to 9 m in SW Crete [2].AlgeriaThe seismicity of this area originates in a continental collision environment characterized by a complex pattern of thrust structures. The strongest earthquake of this region was the M=7.1 El Asnam earthquake in 1980 and there are some historical records of previous strong earthquakes in the past. The scenario here proposed is an attempt to show what could happen if the rupture zone will occur offshore with the same characteristic of the El Asnam earthquake. Constraints came from the well documented studies on the 1980 El Asnam and 2003 Boumerdes earthquakes [3, 4].Southern Tyrrhenian SeaThe seismicity of this area is thought to be the result of the N-S average shortening that accommodates much of the convergence of the Africa and Eurasia plate. Some historical moderate-size earthquakes, eventually mislocated, probably belong to this seismic belt, and at least one of them (in 1823) gave origin to a tsunami. There aren't enough data to guide in the choice of the most likely fault plane from the focal mechanisms, so we propose here the worst-case tsunami scenario.

References[1] Vannucci et al. (2004) Annals of Geophysics, supplement to vol. 47, 1, 247-306. Visit also http://ibogfs.df.unibo.it/user2/paolo/www/startup.html.[2] Pirazzoli et al. (1982) Tectonophysics, 86, 27-43.[3] Ruegg et al. (1982), BSSA, 72, 6, 2227-2244.[4] EERI Reconnaissance Report (2003)

ISC CATALOG

30°W 20°W 10°W 0° 10°E 20°E 30°E 40°E 50°E 60°E

30°N

40°N

50°N

Fig.1 Instrumental seismicity of the Mediterranean region (from ISC Catalog) for depth interval 0-50 km, from [1].

Mw

4.0 4.5 5.0 5.5 6.0

6.5 7.0 7.5 8.0 8.5 9.0

Sard

inia

Southern Italy

Sicily

Fig.3This figure shows the 3 stretches of coastline selected to assess the tsunami impact. Numbers along each stretch represent the distance along the coastline measured in km. They serve as reference for Figs .6 to 8, Figs. 11 to 13 and Figs. 16 to 18 on the right, that represent maximum water heights along the selected coastlines.

Source selection (Fig.2)3 seismogenic zones:

- Algeria (Fig.4): 15 potential sources- Southern Tyrrhenian Sea (Fig.8): 53 potential sources- Hellenic arc sources (Fig.12): 9 potential sources

For each seismogenic zone For each potential source

- calculation of the maximum water height (hmax) on the computational domain Example: sources (Figs.4, 9, 14) hmax (Figs. 5, 10, 15) end For each coastline - maximum and average of hmax (Figs. 6-8,11-13,16-18) - marigrams at selected localities endend

ConclusionsIn the present work we considered 3 seismic zones that are potentially capable to generate tsunamis in the Mediterranean Sea. We focussed our attention to the italian coasts mostly exposed to these tsunamis. We found that a M=7.1 off the coast of Algeria may produce maximum water heigths as large as 1 m along the Sardinia coast. A moderate earthquake generating along the Southern Tyrrhenian structure may induce water height on the order of 0.5 m along the Northern coast of Sicily. The most dangerous tsunamigenic source is a potential M=8 occurring along the Hellenic arc: this event is able to generate a tsunami impacting against the Southern Italy and Sicily coast with water height exceeding 3 m along large stretchs of coast and up to 4 m at several sites. Our approach is well suited to build-up a database of scenario impact due to potential tsunamis in the Mediterranean Sea. This database may be used to assess the tsunami risk on the Mediterranean Sea; furthermore, in case of event occurrence, it may be quickly accessed for a real-time detection of the most exposed coasts and for a rapid evaluation of the tsunami impact.

Fig.9

Fig.10

Fig.11

Fig.12

Fig.13

Fig.14 Fig.15

Fig.16

Fig.17

Fig.18

MAXIMUM AND AVERAGE WATER HEIGHT ALONG SICILY COASTS MAXIMUM AND AVERAGE WATER HEIGHT ALONG SICILY COASTS MAXIMUM AND AVERAGE WATER HEIGHT ALONG SICILY COASTS

0 200 400 600 800 1000

0.1

0.2

0.3

0.4

0.5

0.6

distance (km)

wav

e h

eig

ht

(m) absolute maximum

standard deviation

average

MAXIMUM AND AVERAGE WATER HEIGHT ALONG SARDINIA COASTS

0 200 400 600 800 1000

0.05

0.1

0.15

0.2

distance (km)

wav

e h

eig

ht

(m) absolute maximum

standard deviation

average

MAXIMUM AND AVERAGE WATER HEIGHT ALONG SARDINIA COASTS

0 200 400 600 800 1000 1200

0.2

0.4

0.6

0.8

1

1.2

1.4

distance (km)

wav

e h

eig

ht

(m)

absolute maximum

standard deviation

average

MAXIMUM AND AVERAGE WATER HEIGHT ALONG SARDINIA COASTS

0 200 400 600 800 1000 1200 1400 1600 1800 2000

1

2

3

4

distance (km)

wav

e h

eig

ht

(m) absolute maximum

standard deviation

average

MAXIMUM AND AVERAGE WATER HEIGHT ALONG SOUTHERN ITALY COASTS

0 200 400 600 800 1000 1200 1400 1600 1800 2000

0.02

0.04

0.06

0.08

0.1

0.12

wav

e h

eig

ht

(m)

absolute maximum

standard deviation

average

MAXIMUM AND AVERAGE WATER HEIGHT ALONG SOUTHERN ITALY COASTS

0 200 400 600 800 1000 1200 1400 1600 1800 2000

0.1

0.2

0.3

0.4

0.5

0.6

distance (km)

wav

e h

eig

ht

(m) absolute maximum

standard deviation

average

MAXIMUM AND AVERAGE WATER HEIGHT ALONG SOUTHERN ITALY COASTS

EARTHQUAKE-INDUCED TSUNAMIS IN THE MEDITERRANEAN SEA:SCENARIOS OF POTENTIAL THREATS TO SOUTHERN ITALYStefano Lorito, Alessio Piatanesi, Mara Monica Tiberti and Roberto Basili Istituto Nazionale di Geofisica e Vulcanologia - Rome, Italy

European Geosciences UnionGeneral Assembly 2006

Vienna, Austria, 2 - 7 April 2006

Session Natural Hazards NH6.01Abstract N. EGU06-A-09202

Poster board N. XY0626