The Darwin VAAC reported that on 16 and 18 May ash plumes from Dukono were seen in satellite imagery drifting about 165 km W and NW, respectively, at an altitude of 3 km (10,000 ft) a.s.l.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)

Geological Summary. The Dukono complex in northern Halmahera is on an edifice with a broad, low profile containing multiple peaks and overlapping craters. Almost continuous explosive eruptions, sometimes accompanied by lava flows, have occurred since 1933. During a major eruption in 1550 CE, a lava flow filled in the strait between Halmahera and the Gunung Mamuya cone, 10 km NE. Malupang Wariang, 1 km SW of the summit crater complex, contains a 700 x 570 m crater that has also had reported eruptions.