Report on Gamalama (Indonesia) — 10 October-16 October 2012
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 10 October-16 October 2012
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2012. Report on Gamalama (Indonesia). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 10 October-16 October 2012. Smithsonian Institution and US Geological Survey.
0.8°N, 127.33°E; summit elev. 1715 m
All times are local (unless otherwise noted)
CVGHM reported that eruptions at Gamalama during 15-16 September prompted CVGHM to raise the Alert Level to 3 (on a scale of 1-4) on 16 September. An eruption on 17 September produced a white-and-gray plume that rose 300 m above the crater and drifted E and SE. Ashfall was reported in the ESE part of Ternate (S, SE, and E part of island). After the eruption through 8 October white plumes rose 10-50 m high. Seismicity decreased in early October. The Alert Level was decreased to 2 on 9 October. Visitors and residents were warned not to approach the crater within a radius of 1.5 km.
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.