Megathrust locking encoded in subduction landscapes

Locked areas of subduction megathrusts are increasingly found to coincide with landscape features sculpted over hundreds of kyrs, yet the mechanisms that underlie such correlations remain elusive. We show that interseismic locking gradients induce increments of irreversible strain across the overriding plate manifested predominantly as distributed seismicity. Summing these increments over hundreds of earthquake cycles produces a spatially-variable field of uplift representing the unbalance of co-, post-, and interseismic strain. This long-term uplift explains first-order geomorphological features of subduction zones such as: the position of the continental shelf break, the distribution of marine terraces and peninsulas, and the profile of forearc rivers. Inelastic yielding of the forearc thus encodes short-term locking patterns in subduction landscapes, highlighting the role geomorphology can play in constraining Earth's greatest source of seismic hazard.