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Report on Ibu (Indonesia) — March 2005


Bulletin of the Global Volcanism Network, vol. 30, no. 3 (March 2005)
Managing Editor: Richard Wunderman.

Ibu (Indonesia) Periodic ash emissions during June-August 2004 and inferred dome growth

Please cite this report as:

Global Volcanism Program, 2005. Report on Ibu (Indonesia) (Wunderman, R., ed.). Bulletin of the Global Volcanism Network, 30:3. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN200503-268030



1.488°N, 127.63°E; summit elev. 1325 m

All times are local (unless otherwise noted)

The Directorate of Volcanology and Geological Hazard Mitigation (DVGHM) released ten nearly identical weekly reports on Ibu during 31 May-29 August 2004. They noted that Ibu emitted "white ash" (steam plumes) reaching ~ 50-150 m above the crater rim. Continued growth of the intracrater lava dome was either recognized or assumed. Ibu lacked a working seismic instrument. Its hazard status remained at Level II (Yellow, a condition meaning 'caution or on guard' ('waspada' in Indonesian).

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.

Information Contacts: Directorate of Volcanology and Geological Hazard Mitigation (DVGHM), Jalan Diponegoro No. 57, Bandung 40122, Indonesia (URL: http://www.vsi.esdm.go.id/).