PVMBG reported that during May-June white-and-gray plumes rose as high as 1.2 km above Dukono's Malupang Warirang Crater rim and were accompanied by rumbling and roaring. A powerful explosion on 23 May was followed by minor ashfall in areas to the E. During 1-5 July white-and-gray plumes rose as high as 600 m; minor ashfall was reported in northern areas on 1 July. The Alert Level remained at 2 (on a scale of 1-4). Residents and tourists were advised not to approach the crater within a radius of 2 km.

Based on analyses of satellite imagery and wind data, the Darwin VAAC reported that during 31 June-3 July ash plumes rose to an altitude of 2.1 km (7,000 ft) a.s.l. and drifted 25-165 km NE. On 7 July ash plumes rose to an altitude of 1.8 km (6,000 ft) a.s.l. and drifted 45 km NE.

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.

Sources: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM), Darwin Volcanic Ash Advisory Centre (VAAC)