Gas and seismicity within the Istanbul seismic gap.

Understanding micro-seismicity is a critical question for earthquake hazard assessment. Since the devastating earthquakes of Izmit and Duzce in 1999, the seismicity along the submerged section of North Anatolian Fault within the Sea of Marmara (comprising the "Istanbul seismic gap") has been extensively studied in order to infer its mechanical behaviour (creeping vs locked). So far, the seismicity has been interpreted only in terms of being tectonic-driven, although the Main Marmara Fault (MMF) is known to strike across multiple hydrocarbon gas sources. Here, we show that a large number of the aftershocks that followed the M 5.1 earthquake of July, 25th 2011 in the western Sea of Marmara, occurred within a zone of gas overpressuring in the 1.5-5 km depth range, from where pressurized gas is expected to migrate along the MMF, up to the surface sediment layers. Hence, gas-related processes should also be considered for a complete interpretation of the micro-seismicity (~M < 3) within the Istanbul offshore domain.

Continuous monitoring of noise levels in the Gulf of Catania (Ionian Sea). Study of correlation with ship traffic.

Acoustic noise levels were measured in the Gulf of Catania (Ionian Sea) from July 2012 to May 2013 by a low frequency (<1000Hz) hydrophone, installed on board the NEMO-SN1 multidisciplinary observatory. NEMO-SN1 is a cabled node of EMSO-ERIC, which was deployed at a water depth of 2100m, 25km off Catania. The study area is characterized by the proximity of mid-size harbors and shipping lanes. Measured noise levels were correlated with the passage of ships tracked with a dedicated AIS antenna. Noise power was measured in the frequency range between 10Hz and 1000Hz. Experimental data were compared with the results of a fast numerical model based on AIS data to evaluate the contribution of shipping noise in six consecutive 1/3 octave frequency bands, including the 1/3 octave frequency bands centered at 63Hz and 125Hz, indicated by the Marine Strategy Framework Directive (2008/56/EC).

Geological and seismological evidence of strike-slip displacement along the E-W Adriatic-Central Apennine belt

New geological, geophysical and seismological data produced in the last decade allow an improved definition of the kinematics of the Tyrrhenian Sea-central Apennines-Adriatic Sea system. The integration of these different types of dataset outlines a complex E-W deformational belt running from the Adriatic Sea, at Gargano latitudes, to the Latium-Abruzzi Platform domain (central Apennines). Its possible prosecution in the Tyrrhenian Sea is discussed. This belt has its own seismotectonic characteristics, and divides the Apennines into two zones with different seismotectonic behaviour. All these data were integrated into a multidisciplinary model that results in the introduction of a strike-slip displacement sometimes in Pliocene to recent times along the central Apennines-Adriatic Sea E-W belt. This relative motion can take for the strike-slip block tectonics observed in the central Apennines as well as for the uplift of Gargano and Tremiti Islands areas, including their seismicity. The displacement is related to a differing behaviour of the chain, foreland systems across this bend and can be justified either by assuming a partially active sinking of the southern Adriatic lithosphere or a slower sinking processes in the northern Adriatic one

Use of the Paleomagnetic Databases for geodynamical studies : Some examples from the Mediterranean Region

The publication of Global Paleomagnetic Database allows an easier use of the paleomagnetic data, which are fundamental tools to constraint regional and global geodynamic models. The Stable Africa and Stable Europe, the Arabian plate and finally the Mediterranean region paleomagnetic data, over Mesozoic-Cenozoic, have been critically re-examined using suitable computer programs developed at the Istituto Nazionale di Geofisica. The data have been selected on the basis of space, time and quality filtering with the convinction that the higher quality data are more useful for geodynamic studies, than averaging larger databases without any filtering of original studies. Besides the extraction software, a mapping program to plot sampling localities and paleopoles with associate confidence ellipses, using cartographic projections, enhances the understanding of the mutual relations among groups of paleopole belonging to different areas. The African and European Apparent Polar Wander Paths (APWPs) has been computed, using only higher quality African and European data respectively, and compared with some already published APWPs. Some applications to regional tectonics of the Mediterranean region have been done. In particular Italy and Istria have been considered