Report on Karkar (Papua New Guinea) — July 1980
Scientific Event Alert Network Bulletin, vol. 5, no. 7 (July 1980)
Managing Editor: David Squires.
Karkar (Papua New Guinea) Possible ash emission
Please cite this report as:
Global Volcanism Program, 1980. Report on Karkar (Papua New Guinea). In: Squires, D. (ed.), Scientific Event Alert Network Bulletin, 5:7. Smithsonian Institution. https://doi.org/10.5479/si.GVP.SEAN198007-251030.
Papua New Guinea
4.649°S, 145.964°E; summit elev. 1839 m
All times are local (unless otherwise noted)
"Possible ash emissions were reported on 13, 14, and 15 July. However, an aerial inspection on 29 July did not detect any morphological changes to the crater that might have accompanied the reported ash emissions. Fumarolic activity inside the 1979 crater may have increased. Fumaroles on the E part of the caldera floor may have weakened while those on the W side may have intensified. White sublimates were conspicuous on Bagiai Cone. The seismic recording level was unchanged, and the seismic activity continued to consist of small, probably B-type, shocks, and periods of tremor."
Geologic Background. Karkar is a 19 x 25 km wide, forest-covered island that is truncated by two nested summit calderas. The 5.5-km-wide outer caldera was formed during one or more eruptions, the last of which occurred 9000 years ago. The eccentric 3.2-km-wide inner caldera was formed sometime between 1500 and 800 years ago. Parasitic cones are present on the N and S flanks of this basaltic-to-andesitic volcano; a linear array of small cones extends from the northern rim of the outer caldera nearly to the coast. Most historical eruptions, which date back to 1643, have originated from Bagiai cone, a pyroclastic cone constructed within the steep-walled, 300-m-deep inner caldera. The floor of the caldera is covered by young, mostly unvegetated andesitic lava flows.
Information Contacts: C. McKee, RVO.