Karangetang in Indonesia erupting in June of 2007.

This year we haven't had a lot of news about volcanic activity in Indonesia. This is not to say that eruptions haven't been happening, rather they just haven't been in the news. If you check out the current status of the volcanoes of Indonesia, you'll see that no less than six volcanoes are on orange (Level 2) status and another fourteen are on yellow (Level 1 - and there is a Level 0 as well). So, it is a active arc as arcs go (compare that to the Aleutians or Cascades).

This means that it should come as little surprise that Karangetang on the island of Sulawesi erupted overnight. Based on the reports, it seems that the volcano had a partial dome collapse (possibly aided by heavy rains) that caused a block-and-ash flow to be generated along with potentially a minor explosive column. This eruption was not expected and the collapse happened so rapidly that there were no evacuations and at least four people are dead and more are missing. The local government is now evacuating the nearby villages.

Karangetang is a very active volcano, with frequent small eruptions over the last 10 years, mostly in the VEI 1-2 range. However, just because most eruptions are small doesn't mean you should be lulled into a sense that the volcano is "safe". You can see images of the region around the volcano and some of the small Strombolian explosions that occur frequently at the volcano over on Stromboli Online along with video of an eruption in 2009 (video) from an Indonesian newscast.