GNGTS 2021 - Atti del 39° Convegno Nazionale

GNGTS 2021 S essione 3.2 478 UNDERWATER PHENOMENA DETECTION AND SEA FLOOR CHARACTERIZATION BY CHIRP DATA PROCESSING A. Vesnaver, M. Busetti, L. Baradello Istituto Nazionale di Oceanografia e Geofisica Sperimentale – OGS, Italy Introduction Chirp recording systems provide high-resolution images of the shallow sediments below the sea floor. The obtained signal is almost saturated by multiple reflections from the water bottom and sea surface, while the propagation effects in the water layer are normally ignored, and often are even muted out as noise. Petronio et al. (2009, 2010) showed that amazing patterns show up in the water layer when processing properly multi-channel seismic surveys, i.e., by muting instead the signal from the sea floor downwards. Weak reflections from a few water layers with different density and temperature become visible then, opening the way for the oceanographic use of existing seismic surveys. In this paper, we carry out a comparable work for Chirp data. Fig.1 - Gain recovery by a 4 ms window AGC (A) and by a t 2 function (B).