Report on Gamalama (Indonesia) — 27 July-2 August 2016
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 27 July-2 August 2016
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2016. Report on Gamalama (Indonesia). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 27 July-2 August 2016. Smithsonian Institution and US Geological Survey.
0.8°N, 127.33°E; summit elev. 1715 m
All times are local (unless otherwise noted)
PVMBG reported that at 0628 on 3 August a weak explosion at Gamalama generated an ash plume that rose 500-600 m above the crater and drifted SE and S. Ash emissions declined at 0655. Ashfall was reported in areas on the SSE flank including Ake Huda. The report also noted a brief airport closing. The Alert Level remained at 2 (on a scale of 1-4); visitors and residents were warned not to approach the crater within a 1.5-km radius.
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.