Compilation and processing of bathymetric data recorded along the Northwest African continental margin over several decades

The Northwest (NW) African continental margin is well known for the occurrence of large-scale submarine landslides with prominent scarps exposed at the seafloor. Previous studies primarily focused on major landslides, but rarely covered small scarps. It is unclear if the distribution of landslides along the NW African continental margin is biased by the availability of processed data because data were collected mainly in designated surveys in areas of special interest. Numerous multibeam bathymetric data sets, however, are available for the area as data were also collected during transits and cruises where seafloor mapping was not a primary objective. We compiled such various datasets in the open-source MB-System software and implemented a cloud-based auto-processing and adaptive filtering workflow to handle the large bathymetric datasets (15,476 survey lines). The results show that our auto-processed bathymetric data provide a much-improved view of the seafloor (50 × 50 m), compared to EMODnet2020 and GEBCO 2022 GRID without having manually edited the data. Such a workflow allows to process large underway multibeam datasets of the given kind and therefore it resolves the unknown submarine landforms. Our results from NW Africa offer not only new insights into small-scale submarine landslides but also fulfill the missing piece from previous studies that focused on large-scale submarine landslides. Minor scarps are mainly found close to areas with major landslides, supporting the hypotheses that the NW African continental margin is characterized by large-scale but infrequent landsliding. Minor scarps are additionally identified in some other areas, such as the walls of the Agadir Canyon. Associated landsliding may contribute to the well-known Moroccan Turbidite System. The additional information on minor scarps allows us to gain a more comprehensive understanding of submarine landslides and the associated tsunami risk along the NW African continental margin.