8. Kilauea, Hawai'i (39)
Another consistent performer, Kilauea not only kept up its act at the Halema`uma`u summit crater and the east rift's Pu`u O`o crater, but added a new move. In March, the summit and Pu`u O`o craters dramatically drained and a new fissure opened on the volcano - the quickly named Kamoamoa fissure (see above). The fissure was only active for a few weeks, but it marked the first dramatic change in the style of activity at Kilauea in a few years. Activity returned to the summit and Pu`u O`o later in the year and the volcano started its first ocean entry within the National Park as 2011 closed.
The Kamoamoa Fissure seen on March 6, 2011. Image courtesy of HVO/USGS.