Objective Debris flows are cohesive sediment gravity flows which occur in both subaerial and subaqueous settings.Compared to subaerial debris flows which have been well studied as a geological hazard,subaqueous debris flows showing complicated sediment composition and sedimentary processes were poorly understood.The main objective of Objective Debris flows are cohesive sediment gravity flows which occur in both subaerial and subaqueous settings. Compacted to subaerial debris flows showed both sediment composition and sedimentary processes were poorly understood. The main objective of