Puʻu ʻŌʻō (often written Puu Oo, ], ) is a volcanic cone in the eastern rift zone of the Kīlauea volcano of the Hawaiian Islands. Until the end of April 2018, Puʻu ʻŌʻō had been erupting nearly continuously since January 3, 1983, making it the longest-lived rift-zone eruption of the last two centuries.