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Report on Ibu (Indonesia) — 2 December-8 December 2020


Ibu

Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
2 December-8 December 2020
Managing Editor: Sally Kuhn Sennert

Please cite this report as:

Global Volcanism Program, 2020. Report on Ibu (Indonesia). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 2 December-8 December 2020. Smithsonian Institution and US Geological Survey.

Weekly Report (2 December-8 December 2020)

Ibu

Indonesia

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

All times are local (unless otherwise noted)


PVMBG reported that during 2-8 December gray-and-white ash plume from Ibu rose 200-800 m above the summit and drifted N and E. There were 70-81 eruptive events per day recorded during 2-4 and 6-8 December. The Alert Level remained at 2 (on a scale of 1-4), and the public was warned to stay at least 2 km away from the active crater and 3.5 km away on the N side.

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, contained several small crater lakes through much of historical time. The outer crater, 1.2 km wide, is breached on the north side, creating a steep-walled valley. A large parasitic cone is located ENE of the summit. 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. Only a few eruptions have been recorded in historical time, the first a small explosive eruption from the summit crater in 1911. An eruption producing a lava dome that eventually covered much of the floor of the inner summit crater began in December 1998.

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