Report on Gamalama (Indonesia) — 22 August-28 August 2007
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 22 August-28 August 2007
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2007. Report on Gamalama (Indonesia). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 22 August-28 August 2007. Smithsonian Institution and US Geological Survey.
0.8°N, 127.33°E; summit elev. 1715 m
All times are local (unless otherwise noted)
CVGHM raised the Alert Level of Gamalama on 24 August from 1 to 2 (on a scale of 1-4) due to an increase in activity. Prior to 10 August, diffuse white plumes rose to an altitude of 1.8 km (5,900 ft) a.s.l. then increased in altitude to 2 km (6,600 ft) a.s.l. during 10-23 August. On 23 August, white and gray plumes rose to an altitude of 2.1 km (6,900 ft) a.s.l. Concurrent with the increased Alert Level, government officials banned access within a 2-km radius of the active crater.
Geologic Background. Gamalama is a near-conical stratovolcano that comprises the entire island of Ternate off the western coast of Halmahera, and is one of Indonesia's most active volcanoes. The island was a major regional center in the Portuguese and Dutch spice trade for several centuries, which contributed to the thorough documentation of Gamalama's historical activity. Three cones, progressively younger to the north, form the summit. Several maars and vents define a rift zone, parallel to the Halmahera island arc, that cuts the volcano. Eruptions, recorded frequently since the 16th century, typically originated from the summit craters, although flank eruptions have occurred in 1763, 1770, 1775, and 1962-63.