Seismic Exploration of the Deep Structure and Seismogenic Faults in the Ligurian Sea by Joint Multi Channel and Ocean Bottom Seismic Acquisitions: Preliminary Results of the SEFASILS Cruise

Abstract

Tel.: +33-48361-8779 † Presented as an expanded abstract: Dessa, J.-X.; Beslier, M.-O.; Schenini, L.; Chamot-Rooke, N.; Corradi, N.; Delescluse, M.; Déverchère, J.; Larroque, C.; Miguil, B.M.; Operto, S.; et al. (The SEFASILS Shipboard) Team. Seismic exploration of the deep structure and seismogenic faults in the Ligurian Sea by joint MCS and OBS acquisition: Preliminary results of the SEFASILS cruise.Abstract: The north Ligurian margin is a complex geological area in many ways. It has witnessed several phases of highly contrasting deformation styles, at both crustal scale and that of shallower cover tectonics, simultaneously or in quick succession, and with significant spatial variability. This complex interplay is mirrored in the resulting intricate structures that make it hard to identify active faults responsible for both, the significant seismicity observed, and the tectonic inversion undergone by the margin, identified at longer time scales on morphostructural grounds. We present here the first preliminary results of the leg 1 of SEFASILS cruise, conducted in 2018 offshore Monaco, in an effort to answer these questions by means of modern deep seismic acquisitions, using multichannel reflection and wide-angle sea-bottom records. Some first interpretations are provided and point towards an active basement deformation that focuses at the limits between main crustal domains.

Ambient‐Noise Tomography of the Ligurian‐Provence Basin Using the AlpArray Onshore‐Offshore Network: Insights for the Oceanic Domain Structure

“…These results show the potential of a joint interpretation of V p and V s models since they provide reliable answers to a number of debated questions on the petrological nature of the crust and uppermost mantle of the Ligurian‐Provence basin, at least along the LOBSTER‐P02 seismic profile. They also warrant the same type of study on the SEFASILS controlled‐source seismic profile that crosses the northern margin of the basin (Dessa et al., 2020).…”

An efficient elastic full‐waveform inversion of multiple parameters with ocean‐bottom seismometer data

“…Historically, OBS data facilitated crustal seismic imaging through methodologies like tomography, migration or full waveform inversion (FWI) (Dessa et al., 2004a, b; Górszczyk et al., 2017; Operto, Virieux, & Dessa, 2006; Operto, Virieux, Dessa, & Pascal, 2006; Sears et al., 2008, 2010). More recently, the focus has also shifted to leveraging control‐source, multicomponent OBS records for exploration via FWI (Alves & Biondi, 2018; Dessa et al., 2020; Zhu et al., 2020). The inherent strengths of OBS, such as enhancement of the weak deep reflections, higher signal‐to‐noise ratio, and enabling full‐azimuth recording across different offsets, surpassing traditional towed‐streamer acquisition (Ibrahim & Latham, 1978), significantly bolster the data quality for precise imaging of sub‐seabed structures.…”