Report on Gamkonora (Indonesia) — 25 July-31 July 2007
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 25 July-31 July 2007
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2007. Report on Gamkonora (Indonesia). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 25 July-31 July 2007. Smithsonian Institution and US Geological Survey.
1.38°N, 127.53°E; summit elev. 1635 m
All times are local (unless otherwise noted)
CVGHM lowered the Alert Level for Gamkonora from 3 to 2 (on a scale of 1-4) on 24 July based on visual observations and a decrease in seismicity. That followed a sharp drop in seismicity during 8-23 July, a decline both in terms of the number of events and their energy. Later, during 16-23 July, when breaks in inclement weather took place, observers saw white plumes rising to altitudes of 5.6 km (18,400 ft) a.s.l. Available CVGHM reports issued through the 26 July did not disclose more recent events.
Geologic Background. The shifting of eruption centers on Gamkonora, the highest peak of Halmahera, has produced an elongated series of summit craters along a N-S trending rift. Youthful-looking lava flows originate near the cones of Gunung Alon and Popolojo, south of Gamkonora. Since its first recorded eruption in the 16th century, typical activity has been small-to-moderate explosive eruptions. Its largest historical eruption, in 1673, was accompanied by tsunamis that inundated villages.