GNGTS 2017 - 36° Convegno Nazionale

154 GNGTS 2017 S essione 1.2 References Calò M. and Parisi L.; 2014: Evidences of a lithospheric fault zone in the Sicily Channel continental rift (southern Italy) from instrumental seismicity data . Geophysical Journal International, 199 (1) , art. no. ggu249, pp. 219-225. DOI: 10.1093/gji/ggu249 Civile D., Lodolo E., Tortorici L., Lanzafame and Brancolini, G.; 2008: Relationships between magmatism and tectonics in a continental rift: The Pantelleria Island region (Sicily Channel, Italy) . Marine Geology, 251 , 32- 46. Coltelli M., Cavallaro D., D’Anna G., D’Alessandro A., Grassa F., Mangano G., Patanè D. and Gresta S.; 2016: Exploring the submarine graham bank in the sicily channel . Annals of Geophysics, 59 (2) , art. no. S0208,DOI: 10.4401/ag-6929 Lodolo E., Civile D., Zanolla C. and Geletti R.; 2012: Magnetic signature of the Sicily Channel volcanism . Marine Geophysical Research, 33 (1) , 33-44. DOI: 10.1007/s11001-011-9144-y Mantovani E., Viti M., Babbucci D., Tamburelli C., Cenni N., Baglione M. and D’Intinosante V.; 2014: Generation of Back-Arc Basins as Side Effect of Shortening Processes: Examples from the Central Mediterranean. International Journal of Geosciences, 5 , 1062-1079. doi: 10.4236/ijg.2014.510091. Soumaya A., BenAyed N., Delvaux D. and Ghanmi M.; 2015: Spatial variation of present-day stress field and tectonic regime in Tunisia and surroundings from formal inversion of focal mechanisms: Geodynamic implications for central Mediterranean. Tectonics , 34 , 1154–1180, doi:10.1002/2015TC003895. Insights on the seismotectonics of the Mercure Basin area (southern Italy) by integrated geological and geophysical data: coexistence of shallow extensional and deep strike-slip kinematics L. Ferranti 1,3 , G. Milano 2 , M. Pierro 1 1 Dipartimento di Scienze della Terra, delle Risorse e dell’Ambiente, Università Federico II, Napoli, Italy 2 Istituto Nazionale di Geofisica e Vulcanologia, Osservatorio Vesuviano, Napoli, Italy 3 CRUST, Centro inteRUniversitario per l’analisi Sismotettonica Tridimensionale con applicazioni territoriali, Italy The southern Apennines are characterized by different seismotectonic regimes that affects adjoining regions. Whereas active extension characterizes the ridge and western part of the orogen, strike-slip seismicity is currently found in the eastern part of southern Italy. The boundary between extension and strike-slip deformation is ill-defined, and broadly runs east of the main mountain belt, where large historical and instrumental extensional earthquakes occur. Strike-slip earthquakes in the east have typically deeper (~15-35 km depth) focal depths than extensional earthquakes in the west, the latter being located in the upper ~12-15 km of the crust. In this contribution, we assess the seismotectonics of the western part of the border area between the southern Apennines and Calabrian Arc, centered on the Mercure extensional basin, by integrating recent seismicity with a reconstruction of the structural frame from surface to deep crust. The analysis of low-magnitude (M L ≤3.5) events occurred in the area during 2013-2017, when evaluated in the context of the structural model, has revealed that seismic deformation is complex, that and a variety of different tectonic processes may be at work in this region. This result is partly surprising because existing seismotectonic models hold that the axial part of the southern Apennines experiences solely extension, which is released during moderate and large earthquakes. Instead, low-energy events testify that extensional faulting with ENE-WSW tensile axes in the study area is segregated in the upper crust (above 9 km depth) and is mostly a low-rate prosecution of the so-called Pollino seismic sequence (2009-2012). As published geodetic data show, extensional seismicity is detached from laterally and vertically adjacent crustal domains which are characterized by strike-slip earthquakes. These results are consistent with the last kinematic event recorded on outcropping faults, and with the typical depth and