Karkar volcano as seen from space.

Eruptions reader The Bobs left a note mentioning that there may have been a 'significant' eruption at Karkar in Papua New Guinea. The only place I can find information is John Seach's Volcano Live:

An eruption occurred at Karkar volcano at 6:39 pm on 25th November 2009. The eruption plume reached a height of 45,000 ft. A magnitude 5.1 earthquake hit 90 km SSE of Karkar volcano 7.5 hours before the eruption.

I don't know too much about Karkar, but the GVP says that it is a volcanic island made of a pair of calderas, with the inner caldera formed in the last 1,500 years. Volcano Live mentions a 1997 activity at the volcano (in the form of fumarolic activity), but the GVP lists the last eruption as occurring in 1980. Most eruptions look to be fairly explosive (~VEI 2) from the pyroclastic cone in the inner caldera. Weekly volcano reports from the SI/USGS lists some fumarolic activity from the inner caldera in January 2008.

If the reports are accurate for this new activity, it could definitely be a "significant" eruption. More news as I can find it.

UPDATE 5:30PM 11/23/2009: And more information is found, over at the Volcanism Blog.

UPDATE 6:45PM 11/23/2009: This isn't really an update as such, but I did stumble across these TOMS images of SO2 from a 1979 eruption of Karkar.