Seismicity, seismotectonics and crustal velocity structure of the Messina Strait (Italy)

Luciano Scarfì , Horst Langer , Antonio Scaltrito

The Messina Strait is the most important structural element interrupting the southernmost part of the Alpine-Apenninic orogenic belt, known as the Calabro-Peloritan Arc. It is being a narrow fan-shaped basin linking the Ionian Sea to the Tyrrhenian Sea. This region is affected by considerable seismic activity which mirrors the geodynamic processes due to the convergence between the African and the Eurasian plates. In the last four centuries, a significant number of disastrous earthquakes originated along the Arc. Among these, the most noteworthy event occurred on December 28, 1908 (known as the Reggio Calabria-Messina earthquake), in the Messina Strait area and caused a large tsunami and more than 100,000 casualties. In this research we focus on the relationships between the general tectonic setting, which characterize the Messina Strait and adjacent areas, seismicity patterns and the crustal structure. We analyzed a data set consisting of more than 300 events occurring in the years from 1999 to 2007, having a magnitude range from 1.0 to 3.8. This data set was exploited in a local earthquake tomography, by carrying out a simultaneous inversion of both the three-dimensional velocity structure and the distribution of seismic foci. We applied the "tomoADD" algorithm, which uses a combination of absolute and differential arrival times and a concept of self-adapting grid geometry, accounting for ray density encountered across the volume. With this method the accuracy of event locations is improved and velocity structure near the source region is resolved in more detail than standard tomography.

Mots clés: Crustal structure; Focal mechanism; Seismicity; Seismotectonics; Tomography

Luciano Scarfì, Horst Langer, Antonio Scaltrito. Seismicity, seismotectonics and crustal velocity structure of the Messina Strait (Italy). Physics of the Earth and Planetary Interiors, 2009, 177 (1-2), pp.65. ⟨10.1016/j.pepi.2009.07.010⟩. ⟨hal-00585471⟩