Papua New Guinea: Minimal risk from submarine volcanic eruption

Earthquake activity reported in PNG and Bougainville over 6-8 May has now been identified as an underwater eruption approximately 140km southeast of Manus Island in the Bismarck Sea. As of 1 June, the eruption continues to cause large ash plumes and earthquake activity near the active site.

Assessment: While the eruption is causing large ash plumes and destroying marine wildlife in the immediate area, multiple scientific organisations assess that there is little risk of an explosive eruption due to the plates in the area separating rather than subducting. According to the NASA Earth Observatory, the likely scenario is a continuation of the slow eruption and formation of a new island. The closest inhabited island is 100km to the northwest and carries a minor risk of tidal surges.

Sources: “Central Bismarck sea Volcano,” Volcano Discovery, 1 June 2026; “Possible Eruption of an Underwater Volcano in the Bismarck Sea,” GEOMAR, 22 May 26; “New Eruption in the Bismarck Sea,” NASA Earth Observatory, 21 May 2026; Patrick Martin and Dana Kirimof, “Undersea volcano erupts in Papua New Guinea's Bismarck Sea prompting tsunami concerns,” RNZ, 19 May 2026.