The North Island Volcanic Plateau occupies the center of the island. Lake Taupo, New Zealand's largest lake, sits in a volcanic caldera formed during a violent eruption 2000 years ago. The volcanic peaks of Mount Tongariro (1,978 m), Mount Ngauruhoe (2,291 m), and Mount Ruapehu (2,797 m) lie south of Lake Taupo. Much of the plateau is covered lava fields, volcanic mudflows (lahars), and deposits of volcanic ash.