Report on Gamkonora (Indonesia) — 4 July-10 July 2007
Smithsonian Institution / US Geological Survey
Weekly Volcanic Activity Report, 4 July-10 July 2007
Managing Editor: Sally Sennert.
Please cite this report as:
Global Volcanism Program, 2007. Report on Gamkonora (Indonesia) (Sennert, S, ed.). Weekly Volcanic Activity Report, 4 July-10 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)
On 8 July, a phreatic eruption from Gamkonora produced an ash plume that rose to an altitude of 1.8 km (5,900 ft) a.s.l. The plume drifted N and ashfall was reported from villages as far as 7 km downwind. The Alert Level was raised to 2 (on a scale of 1-4). On 9 July, seismic activity increased and eruption plumes rose to altitudes of 2.1-2.6 km (7,000-8,500 ft) a.s.l. The Alert Level was raised to 3. Later that day, ash plumes rose to an altitude of 5.6 km (18,400 ft) a.s.l. and the Alert Level was raised to 4. During 9-10 July, incandescent material was propelled 5-50 m above the crater. On 10 July, booming noises were followed by ash plumes that rose to 4.1 km (13,500 ft) a.s.l. About 8,400 people evacuated from villages within an 8 km radius of the volcano.
Geological Summary. 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.