Structural architecture and active deformation pattern in the northern sector of the Aeolian-Tindari-Letojanni fault system (SE Tyrrhenian Sea-NE Sicily) from integrated analysis of field, marine geophysical, seismological and geodetic data

Fabrizio Cultrera (1), Giovanni Barreca (1,7), Luigi Ferranti (2,7), Carmelo Monaco (1,7), Fabrizio Pepe (3), Salvatore Passaro (4), Graziella Barberi (5), Valentina Bruno (5), Pierfrancesco Burrato (6), Mario Mattia (5), Carla Musumeci (5) & Luciano Scarfì (5)
(1) Dipartimento di Scienze Biologiche, Geologiche e Ambientali - Sezione di Scienze della Terra, Università di Catania. Corresponding author e-mail: fcultrera@unict.it.
(2) Dipartimento di Scienze della Terra, delle Risorse e dell'Ambiente, Università di Napoli "Federico II".
(3) Dipartimento di Scienze della Terra e del Mare, Università di Palermo.
(4) Istituto per l'Ambiente Marino Costiero, C.N.R. Napoli.
(5) Istituto Nazionale di Geofisica e Vulcanologia, Osservatorio etneo, Catania.
(6) Istituto Nazionale di Geofisica e Vulcanologia, Roma 1.
(7) CRUST - Centro Interuniversitario per l'Analisi Sismotettonica Tridimensionale con applicazioni territoriali.

Framed in the current geodynamics of the central Mediterranean, the Aeolian-Tindari-Letojanni fault system is part of a wider NW-SE oriented right-lateral wrench zone which accommodates diverging motion between regional-scale blocks located at the southern edge of the Calabrian Arc. In order to investigate the structural architecture and the active deformation pattern of the northern sector of this tectonic feature, structural observations on-land, high and very-high resolution seismic reflection profiles, swath bathymetry and seismological and geodetic data were merged from the Lipari-Vulcano volcanic complex (central sector of the Aeolian Islands) to the Peloritani Mountains across the Gulf of Patti. Our interpretation shows that the active deformation pattern of the study area is currently expressed by NW-SE trending, right-transtensional én-echelon fault segments whose overlapping gives rise to releasing stepover and pull-apart structures. This structural architecture has favored magma and fluid ascent and the shaping of the Lipari-Vulcano volcanic complex. Similarly, the Gulf of Patti is interpreted as an extensional relay zone between two overlapping, right-lateral NW-SE trending master faults. The structural configuration we reconstruct is also supported by seismological and geodetic data which are consistent with kinematics of the mapped faults. Notably, most of the low-magnitude instrumental seismicity occurs within the relay zones, whilst the largest historical earthquakes (1786, Mw=6.2; 1978, Mw=6.1) are located along the major fault segments.

Southern Tyrrhenian sea, NE Sicily, seismic reflection profiles, structural analysis, seismology, GPS geodesy.