Report on Ibu (Indonesia) — November 2015
Bulletin of the Global Volcanism Network, vol. 40, no. 11 (November 2015)
Managing Editor: Edward Venzke. Report research and preparation by: Paul Berger.
Ibu (Indonesia) Continued lava dome growth with occasional weak plumes through November 2015
Please cite this report as:
Global Volcanism Program, 2015. Report on Ibu (Indonesia). In: Venzke, E (ed.), Bulletin of the Global Volcanism Network, 40:11. Smithsonian Institution.
1.488°N, 127.63°E; summit elev. 1325 m
All times are local (unless otherwise noted)
During the latter half of 2013, Ibu's lava dome continued to grow, and observers noted incandescent material and occasional weak white-to-gray plumes (BGVN 38:11). This report discusses activity between March 2014 and November 2015.
Reports from the Center of Volcanology and Geological Hazard Mitigation (CVGHM) indicated that during 1 August-17 November 2015 white-to-gray plumes rose as high as 500 m above the craters. Seismicity during this period was dominated by signals indicating surface or near-surface activity, and continuing lava dome growth in the N part of the crater. The Alert Level remained at 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 on the N side.
Thermal anomalies, based on MODIS satellite instruments analyzed using the MODVOLC algorithm, were observed frequently, and ranged from 1/month (February 2016) to 11/month (July 2014, April 2015, May 2015). Most were one pixel, but three pixels were observed on 5 September 2014 and 22 November 2014. The MIROVA (Middle InfraRed Observation of Volcanic Activity) volcano hotspot detection system, also based on analysis of MODIS data, detected numerous, almost continuous anomalies during the past year, though the frequency decreased from almost daily to averaging a few anomalies per week starting in late October 2015.
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.
Information Contacts: Center of Volcanology and Geological Hazard Mitigation (CVGHM, also known as PVMBG), Saut Simatupang, 57, Bandung 40122, Indonesia (URL: http://vsi.esdm.go.id/); Hawai'i Institute of Geophysics and Planetology (HIGP) MODVOLC Thermal Alerts System, School of Ocean and Earth Science and Technology (SOEST), Univ. of Hawai'i, 2525 Correa Road, Honolulu, HI 96822, USA (URL: http://modis.higp.hawaii.edu/); MIROVA, a collaborative project between the Universities of Turin and Florence (Italy) supported by the Centre for Volcanic Risk of the Italian Civil Protection Department (URL: http://www.mirovaweb.it/).