The north part of the line is part of the Periadriatic Seam that separates the Southern Alps from the nappe stacks of the Central Alps and runs from west to east along the Alpine mountain chain. The Periadriatic Seam branches off to the west at the upper Val di Sole, where it is called the Tonale line. The northeast-oriented Giudicárie line off-sets the (east-west) Periadriatic Seam by 100 kilometers.