Figure 7 Figure 7.
Elastic deformation builds up between great earthquakes if the thrust fault is locked.
The seaward edge of the continent is dragged down and a flexural bulge forms farther landward. During a great earthquake, there is uplift of the seaward edge and collapse of the flexural bulge. The abrupt uplift generates the tsunami, and the collapse of the bulge causes the subsidence recorded in buried coastal marshes. Figure 8 Figure 8. The remainder of the shortening is across the continental shelf.