Abstract: As an active convergent margin, the Sunda Arc is renowned for intense seismic activity, tsunamis, and volcanic eruptions, yet relatively less attention has been paid to the eastern segment of the Sunda Arc. This study describes the along-strike variations of the subducting oceanic crust, trench, and accretionary wedge from eastern Java to Sumbawa Island, and investigates the control of subducting plate topography on the deformation of the overriding plate, and reveals the influence of subduction on shallow geological hazards. The results show significant segmentation of the subduction structure in the study area: the western part controlled by the subduction of the Roo Rise, while the eastern part associated with the subduction of the Argo Abyssal Plain. The distinct seafloor topography and structures of the subducting plate lead to pronounced variations of trench and forearc deformation. The subduction of the Roo Rise results in prominent subduction erosion with a narrow and steeply inclined accretionary wedge. In contrast, that of the abyssal plain corresponds to the development of a broad and gently sloping accretionary wedge. Both seamount/rise subduction and normal faulting generated by plate bending may trigger geological hazards. These findings provide a theoretical basis for understanding accretion processes of subduction zone, as well as earthquake and tsunami hazards.

Key words: Seamount subduction, geological hazards, Java trench, subduction zone, plate margin