Formed as the full width of the river plummets in a single vertical drop into a transverse chasm 1708 meters (5604 ft) wide, carved by its waters along a fracture zone in the basalt plateau. The depth of the chasm, called the First Gorge, varies from 80 meters (260 ft) at its western end to 108 meters (354 ft) in the center. The only outlet to the First Gorge is a 110 meters (360 ft) wide gap about two-thirds of the way across the width of the falls from the western end, through which the whole volume of the river pours into the Victoria Falls gorges.