New satellite pictures from NASA show the dark brown smoke and ash plume originating from Mt. Etna stretching for hundreds of miles over the Mediterranean Sea. The Moderate Resolution Imaging Spectroradiometer (MODIS) instrument on NASA's Terra satellite captured a spectacular true-color images of the eruption. A long, grayish-brown plume of ash and smoke is streaming southward from the volcano.

Top: October 27; Middle: October 28; Bottom: October 29. Images courtesy MODIS Rapid Response Team at NASA GSFC

Located on the island of Sicily, Etna is one of the most studied volcanoes on Earth. Just last summer, French scientists reported that Etna appeared to be undergoing a gradual shift from being a "hot spot" volcano, in which magma wells up from within the Earth, to an "island arc" volcano, in which magma is produced from the collision of tectonic plates. In keeping with that idea, this most recent eruption occurred after a series of hundreds of small earthquakes affected eastern Sicily. Unfortunately for area residents, the transition from a hot-spot volcano to a island-arc volcano signals the potential for greater danger, as the latter produces explosive, as opposed to oozing, eruptions.