• basin architecture;
  • critical wedge;
  • erosion;
  • tectonics;
  • topography

[1] The contemporary presence of the Puli Topographic Embayment within the Taiwanese thrust belt provides insight into processes that initiate and maintain a subcritical state in a thin-skinned compressive wedge. Orogen-scale analyses of Taiwan have succeeded in describing the processes and interactions that affect overall development of the thrust belt; however, relatively little is known about which processes or boundary conditions control first-order organization of strain at intermediate scales within the orogenic wedge. We investigate spatial and temporal scales of variation in the overall topographic and structural architecture of a critical wedge and explore the boundary conditions that affect very rapid shortening and erosion at intermediate scales on the order of 101 kilometers and 104–105 years. Causal links between the structural and synorogenic stratigraphic architecture of the foreland basin and coincidence of the Puli Topographic Embayment provide a valuable case study of the effects of changing boundary conditions (e.g., variable erodibility or strength of rocks along strike) controlling the evolution of critically tapered thin-skinned orogens. Deeper incision of river networks into a thicker sequence of unconsolidated synorogenic sediments in the central western foreland may affect the onset of a topographically subcritical state.