Mt. Stromboli has been in almost continuous eruption for the past 2,000 years. A pattern of eruption is maintained in which explosions occur at the summit craters with mild to moderate eruptions of incandescent volcanic bombs at intervals ranging from minutes to hours. This Strombolian eruption as it is known is also observed at other volcanoes worldwide. Eruptions from the summit craters typically result in a few short-lasting mild but energetic bursts ranging up to a few hundred meters in height containing ash, incandescent lava fragments and lithic blocks. Mt. Stromboli's activity is almost exclusively explosive, but lava flows do occur at times when volcanic activity is high: an effusive eruption in 2002, the first in 17 years, occurred again in 2003 and 2007.