The ocean floor hosts a tremendous variety of forms that reflect the action of a range of tectonic, sedimentary, oceanographic and biological processes at multiple spatio-temporal scales. Being able to map the form and shape of the seabed and to understand the processes that shape it is a major prerequisite to ocean and coastal management, nature conservation and hazard assessment as well as a key objective of national and international research programmes and IODP expeditions.

High quality seafloor maps are integral to submarine geomorphic investigations. Acoustic remote-sensing technologies (singlebeam, multibeam, sidescan, interferometric and synthetic-aperture sonars), deployed on various platforms, are fundamental to seafloor mapping. In relatively shallow and transparent waters, optical methods such as aircraft and satellite-based remote sensing and LIDAR are being employed with increasing success. Seafloor maps, especially when combined with sub-seafloor and/or seabed measurements, provide an exciting opportunity to integrate the approaches of geomorphology and geophysics, and to extend quantitative geomorphology offshore. 3D seismic reflection data has also given birth to the discipline of seismic geomorphology, which has provided a 4D perspective to continental margin evolution. Innovative processing and classification software, image analysis, machine and deep-learning applications are advancing developments in seabed-recognition techniques.

The aim of this interdisciplinary session is two-fold: (i) to highlight recent advances in seabed mapping and classification, and (ii) to improve the understanding of the causes and consequences of geomorphic processes shaping underwater landscapes, including submarine erosion and depositional processes, submarine landslides, sediment transfer and deformation, volcanic activity, fluid migration and escape, faulting and folding, among others. Contributions to this session can include work from any physiographic region, ranging from shallow coastal settings to abyssal plains and deep-sea trenches. Datasets of any scale, from satellite-predicted depth to ultra-high resolution swath bathymetry, sub-surface imaging and sampling, are anticipated.