"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."

Geological Summary. Karkar is a 19 x 25 km forest-covered island that is truncated by two nested summit calderas. The 5.5 km outer caldera was formed during one or more eruptions, the last of which occurred 9,000 years ago. The steep-walled 300-m-deep, 3.2 km diameter, inner caldera was formed sometime between 1,500 and 800 years ago. 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. Recorded eruptions date back to 1643 from Bagiai, a pyroclastic cone constructed within the inner caldera, the floor of which is covered by young, mostly unvegetated andesitic lava flows.

Information Contacts: C. McKee, RVO.