Gas seepage from the deep seafloor produces characteristic geomorphological features, most notably pockmarks, and is commonly associated with focused fluid migration pathways and subsurface structural controls. Probabilistic models based on 3D seismic seafloor mapping and multilevel composition predicted an extensive high likelihood of gas-seep related pockmarks in the Nile deep-sea fan at the southern part of Israel’s Exclusive Economic Zone (EEZ). This led to propose the establishment of Southern Fan marine protected area (MPA). However, so far there have been no direct high-resolution seafloor observations from this region.
To explore seafloor features and provide ground-truth validation, we collected high-resolution side-scan sonar data in August–September 2025 within the proposed MPA. The survey was conducted aboard R/V Bat-Galim at water depths of 1,000-1,200 m using an Edgetech 4205 system. Approximately 175 km of survey lines yielded ~29.5 km² of high-resolution detailed acoustic imagery. The data was used to investigate the seafloor morphology.
The analysis identified 850 seafloor targets, classified into geomorphological categories, including pockmarks, rocky seabed, cellular and chaotic lineated seabed, mounds, and small scattered objects of interest. These features span spatial scales from a few meters to several hundred meters and locally occur at varying mid- to high densities, revealing a highly heterogeneous seafloor that distinguishes this area from the surrounding abyssal plain.
Comparison with existing pockmark prediction models shows partial to strong spatial correspondence, supporting the general validity of the model while also revealing substantial seafloor complexity not predicted from seismic data alone. Several areas where multiple morphologies co-occur were identified as priority sites for follow-up ROV investigation. These results show the importance of near-bottom, high-resolution acoustic imaging like side-scan sonar for constraining deep-sea geomorphology and gas-seep related seafloor processes in the Israeli EEZ, and contribute to the mapping and preservation of unique seafloor habitats and their associated ecosystems.