The largest number of PNG’s active volcanoes are to be found in an arc along the southern margin of the Bismarck Sea: it extends from Bam Island in East Sepik Province to Rabaul at the eastern tip of New Britain. Another volcanic arc trends northeast through Bougainville Island and some smaller islands to the east of New Ireland to the Admiralties, on the northern margin of the Bismarck Sea. There is a cluster of active volcanoes in Oro Province, on the New Guinea mainland, and in islands of the d’Entrecasteaux group to the southeast, in Milne Bay Province. The 14 volcanoes for which written records of eruption are available are considered to be still active.
The worst recorded disasters have been: the tidal wave which followed the collapse of the volcanic crater of Ritter Island, between New Britain and New Guinea, in 1888 (several hundred killed); the eruption of Matupi in Rabaul harbor in 1937 (over 500 killed); and the explosion of Mt Lamington in Oro Province in 1951 (almost 3,000 killed). Within the last 50 years eruptions have occurred at Karkar, Manam and Long Islands in Madang Province, Mt Bagana on Bougainville in North Solomons Province and Mt Ulawun and Mt Langila in New Britain. In 1984 many people were evacuated from Rabaul after vulcanologists warned of an impending serious eruption which, however, has not yet occurred. Stories related to volcanic explosions appear in myths in many parts of PNG.