An active margin is a type of continental margin that is tectonically active, typically characterized by the presence of a convergent plate boundary where an oceanic plate is being subducted beneath a continental plate. Active margins are associated with features such as deep ocean trenches, volcanic arcs, and high seismic activity. They contrast with passive margins, which are tectonically inactive.
Reference: Orme, A. R. “1.10 Tectonism, Climate, and Geomorphology.” Treatise on Geomorphology 1 (2013): 146.