Global Volcanism Program | Image GVP-00450
Phreatic explosions from Motmot Island in Lake Wisdom, on Long Island, during a 1953-54 eruption. The Surtseyan explosion produced a jet of steam and ash seen rising above the lake, and a base surge traveling radially away from the vent across the surface. The western wall of the 10 x 12.5 km Long Island caldera is 200-300 m high in the distance. Twentieth century eruptions at Long Island have originated from vents at or near Motmot Island.
Photo by John Best (courtesy of Wally Johnson, Australia Bureau of Mineral Resources).