Twin volcanic plumes—one of ash, one of gas—rose from Sicily’ Mount Etna on the morning of October 26, 2013. L’Istituto Nazionale di Geofisica e Vulcanologia (INGV) Osservatorio Etneo (National Institute of Geophysics and Volcanology Etna Observatory) reported that Etna was experiencing its first paroxysm in six months. Multiple eruption columns are common at Etna, a result of complex plumbing within the volcano. The Northeast Crater, one of several on Etna’s summit, was emitting the ash column, while the New Southeast Crater was simultaneously venting mostly gas.

This natural-color image (top) collected by Landsat 8 shows the view from space at 11:38 a.m. local time. The towering, gas-rich plume cast a dark shadow over the lower, ash-rich plume and Etna’s northwestern flank. Relatively fresh lava flows (less than a century or so old) are dark gray; vegetation is green; and the tile-roofed buildings of Bronte and Biancavilla lend the towns an ochre hue.

An early-morning photograph taken by Boris Behncke (a volcanologist at the Osservatorio Etneo) reveals the structure of the plumes. The Northeast Crater plume (right) consisted primarily of gray ash, and rose about 1 kilometer (0.6 miles) above the summit. Fragments of volcanic material, atomized by vigorous lava fountains, darkened the base of the New Southeast Crater plume. Strong outgassing associated with the lava fountains carried the plume 1 or 2 kilometers higher then the Northeast Crater plume.

NASA Earth Observatory image by Jesse Allen and Robert Simmon, using Landsat data from the USGS Earth Explorer. Photograph ©2013, Boris Behncke. Caption by Robert Simmon with contributions from Boris Behncke.