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Report on Ibu (Indonesia) — 25 July-31 July 2018

Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 25 July-31 July 2018
Managing Editor: Sally Kuhn Sennert

Please cite this report as:

Global Volcanism Program, 2018. Report on Ibu (Indonesia). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 25 July-31 July 2018. Smithsonian Institution and US Geological Survey.

Volcano Profile |  Weekly Report (25 July-31 July 2018)


Ibu

Indonesia

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

All times are local (unless otherwise noted)


PVMBG reported that at 1852 on 28 July an event at Ibu generated an ash plume that rose 5.5 km above the crater rim and drifted SE. An event at 1612 on 29 July produced an ash plume that rose 4.8 km and drifted N. Ash plumes later drifted SE. Seismic signals for both events were characterized by explosions and avalanches. 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.

Geologic Background. 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.

Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)