The effects of syncontractional sedimentation and erosion on simple, critically tapered Coulomb wedges were evaluated by conducting twelve two-dimensional analog model sandbox experiments. All 12 models produced critically tapered Coulomb wedges with topographic slopes of 6–10° above horizontal basal detachments. The model without syncontractional sedimentation or erosion exhibited a general forward-breaking sequence with synchronous thrust activity. Syncontractional sedimentation produced longer wedges composed of fewer major forward-vergent thrusts and lowered thrust activities in the foreland. Syncontractional erosion inhibited forward propagation of the deformation front, decreased the number of major thrusts, and increased thrust activities in the hinterland. Where combined, the...