Fig. 2: Reference models showing plate motion and deformation in response to slab detachment.

a Ridge-trench collision without plate boundary weakness (PBW) on the subducting plate. b Ridge-trench collision with mid-ocean ridge on the subducting plate. c Continental-trench collision without PBW on the subducting plate. d Continent-trench collision with mid-ocean ridge on the subducting plate. The velocity profile on the top of each panel is obtained at the depth of y = 28 km (i.e., 8 km below the initial surface) in the model. Velocity is positive to the right and negative to the left. The upper and lower model snapshots display the onset of slab detachment and subsequent vigorous mantle flows, respectively. The time of the lower snapshot is relative to the upper snapshot. The bottom of each panel shows the topographic evolution over model time, with the green dashed line indicating the onset time of slab detachment. Color palettes at the figure base represent viscosity, mantle flow velocity, and elevation from left to right. MOR Mid-ocean ridge, RTC Ridge-trench collision, CTC Continent-trench collision.