Concept of deformation of the forearc shelf-basin and subsequent results for the model of continuous transport. When the forearc shelf can no longer be subducted, transport by the Pacific Plate compresses the forearc shelf against the North American Plate, both locking the thrust fault of M-1 (RTB-thrust) and deforming the forearc shelf-basin. As the Pacific Plate plunges downward, a blind decollement separates the forearc shelf from the plate, and the decollement propagates oceanward as transport continues. As implied, sedimentary rocks derived from uplifts of the forearc shelf may eventually be deformed by the propagating decollement and its associated deformation front. The trench is the contemporary toe of the growing sedimentary shelf as described in Fig. 9. The ridge area of Fig. 2 is noted, and it is bounded by the RTB-thrust.

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