Report on Gamalama (Indonesia) — 29 October-4 November 2003
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 29 October-4 November 2003
Managing Editor: Gari Mayberry
Please cite this report as:
Global Volcanism Program, 2003. Report on Gamalama (Indonesia). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 29 October-4 November 2003. Smithsonian Institution and US Geological Survey.
0.8°N, 127.33°E; summit elev. 1715 m
All times are local (unless otherwise noted)
Volcanic activity decreased at Gamalama during 6-12 October, leading DVGHM to reduce the Alert Level from 2 to 1 (on a scale of 1-4) on 13 October. During the report period, gas emissions rose to ~50 m above the summit and the number of daily earthquakes decreased to normal levels.
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.