Report on Ibu (Indonesia) — 4 December-10 December 2013
Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
4 December-10 December 2013
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2013. Report on Ibu (Indonesia). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 4 December-10 December 2013. Smithsonian Institution and US Geological Survey.
1.488°N, 127.63°E; summit elev. 1325 m
All times are local (unless otherwise noted)
PVMBG reported that during 7 June-9 December white-to-gray plumes rose from Ibu’s craters. Observers in Goin (7 km NNW) noted that the lava dome, which had grown taller than the N crater rim in June, continued to grow; incandescent material from the dome filled the river valley in the direction of the Duono Village, about 5 km NW. Seismicity remained relatively stable. On 10 December the Alert Level was lowered to 2 (on a scale of 1-4). The public was warned to stay at least 2 km away from the active crater, and 3.5 km away from the N part.
Geological Summary. The truncated summit of Gunung Ibu stratovolcano along the NW coast of Halmahera Island has large nested summit craters. The inner crater, 1 km wide and 400 m deep, has contained several small crater lakes. The 1.2-km-wide outer crater is breached on the N, creating a steep-walled valley. A large cone grew ENE of the summit, and a smaller one to the WSW has fed a lava flow down the W flank. A group of maars is located below the N and W flanks. The first observed and recorded eruption was a small explosion from the summit crater in 1911. Eruptive activity began again in December 1998, producing a lava dome that eventually covered much of the floor of the inner summit crater along with ongoing explosive ash emissions.