Report on Gamalama (Indonesia) — November 1991
Bulletin of the Global Volcanism Network, vol. 16, no. 11 (November 1991)
Managing Editor: Lindsay McClelland
Gamalama (Indonesia) Seismicity increases but no change in surface activity
Please cite this report as:
Global Volcanism Program, 1991. Report on Gamalama (Indonesia). In: McClelland, L (ed.), Bulletin of the Global Volcanism Network, 16:11. Smithsonian Institution. http://dx.doi.org/10.5479/si.GVP.BGVN199111-268060.
0.8°N, 127.33°E; summit elev. 1715 m
All times are local (unless otherwise noted)
Increased volcanic seismicity was recorded in early December, with the number of events rising from 24/day in the first week to 32/day the second week of the month. Typically, no more than five volcanic earthquakes are recorded daily at Gamalama. Surface activity was limited to low-pressure emission of vapor, rising 100-150 m above the crater rim.
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.
Information Contacts: VSI.