The Juan e Fuca Plate, named after the explorer, is a tectonic plate arising from the Juan de Fuca Ridge, and subducting under the northerly portion of the western side of the North American Plate at the Cascadia subduction zone. It is bounded on the south by the Blanco Fracture Zone, on the north by the Nootka Fault, and along the west by the Pacific Plate. The Juan de Fuca Plate was originally part of the once-vast Farallon Plate, now largely subducted under the North American Plate, and has since fractured into three pieces. The plate name is in some references applied to the entire plate east of the undersea spreading zone, and in other references only to the central piece. When so distinguished, the piece to the south is known as the Gorda Plate and the piece to the north is known as the Explorer Plate. The separate pieces are demarcated by the large offsets of the undersea spreading zone manifested in the above mentioned fracture zone and fault.