Report on Ibu (Indonesia) — 17 May-23 May 2023
Smithsonian Institution / US Geological Survey
Weekly Volcanic Activity Report, 17 May-23 May 2023
Managing Editor: Sally Sennert.
Please cite this report as:
Global Volcanism Program, 2023. Report on Ibu (Indonesia) (Sennert, S, ed.). Weekly Volcanic Activity Report, 17 May-23 May 2023. 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 Ibu continued to erupt during 18-23 May. An average of approximately 80 eruption-related earthquakes were recorded by the seismic network during 18-22 May. White-and-gray emissions of variable densities rose as high as 1 km above the summit and drifted N, E, SE, and W. At 2021 and 2140 on 21 May dense gray ash plumes rose 600 m and 1 km above the summit, respectively, and drifted W. The Alert Level remained at a 2 (the second highest level on a four-level scale), and the public was advised to stay outside of the 2 km hazard radius, and to stay 3.5 km away from the N area of the active crater.
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.