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The CROP95-M18 seismic profile was acquired in 1995 as part of the "CROsta Profonda" project, a regional survey carried out to explore the deeper structures of the Earth's crust in Italy. Although the high energy of the source allowed a high penetration depth, the vintage stacked section showed some areas of low signal-to-noise ratio, due to the acquisition in shallow water environments and related reverberations of surface and guided-waves. To improve the quality of the image, we reprocessed the 2D seismic line with the up-to-date processing techniques by adopting a specific workflow in time domain up to pre-stack time migration. In addition, we created an accurate interval velocity model by combining the coherency inversion technique and reflection tomography. This resulted in depth migration of the uppermost part of the profile (to a depth of 9 km), which was confirmed by the stratigraphy of the Amanda 1bis well. The reprocessing significantly improved the image of the profile and enabled new information on the seismo-stratigraphy to be gleaned from the vintage data. This was particularly important for science and research, as new seismic data with high penetration depths, such as the CROP profiles, are currently difficult to acquire. [ABSTRACT FROM AUTHOR]

Local and regional earthquakes recorded in 2007 by two seismic arrays at Gran Sasso (Italy), one located at surface and one at 1.4 km depth, have been analyzed. Polarization properties of the seismic wavefield have been estimated at both arrays on a short sliding window and in several frequency bands. Array methods were also applied, and the estimated slowness and backazimuth were used to compute the stacking of phase shifted signals in order to improve the signal to noise ratio. Results of polarization computed over single station and array stacked signals have been compared between the two arrays. A well defined polarization azimuth, roughly perpendicular to the main massif ridges, is evident at surface in a broad frequency band. This is observed for earthquake body waves and coda waves. On the contrary, underground the same effect is slightly visible only at very low frequency. [ABSTRACT FROM AUTHOR]

This work deals with the reprocessing of the M12A CROP marine seismic profile, that crosses the northern Tyrrhenian Sea, south of Elba Island. The reprocessing was carried out to improve the visibility and resolution of the structures corresponding to the lower crust (two-way traveltimes lower than 4 s) that are located at depth. In this time window, we apply recently developed methodologies to enhance the signal-to-noise ratio, paying particular attention to the suppression of the short and long period reverberations and to the velocity model building for depth migration. The velocity field used for the depth conversion is iteratively updated by means of the migration velocity analysis on common image gathers. The final products of this work are time and post-stack, depthmigrated sections that can contribute to the understanding of the structural complexity of the investigated area. [ABSTRACT FROM AUTHOR]