a narrow deep-sea depression in the Pacific Ocean that stretches along the foot of the Andes. The trench has a length of 2,200 km, widths ranging from 30 km to 90 km, and a maximum depth of 8,069 m. It forms a typical seam: on the eastern edge is a continental margin; on the western edge, a typical oceanic crust; and in the axial zone, the trench forms a wedge.