9. Sakurajima, Japan (16)
If anything, Sakurajima is consistent. The Japanese volcano produces thousands of small explosions per year (see above) - meaning that you rarely get a large explosion but on any given day, if you turn on one of the many webcams pointed at the volcano, you're likely to see something. Sakurajima begun the year as part of a duo of volcanoes erupting in Japan - starting a very active (and tragic) geologic year for the island nation.
Sakurajima erupting in early 2011. Image courtesy of James Reynolds - check out his year end video with shots from Sakurajima erupting.