Mount Ruang, a stratovolcano in the Indonesian Sulawesi Islands, erupted on September 25, 2002, sending a large plume of ash (gray pixels) streaming westward toward Borneo and Sumatra. The eruption was preceded by earthquakes on the day before, followed by a thick, black column of volcanic ash ejected as high as 5,000 m into the sky on the 25th. While no fatalities were reported, more than 1,000 residents on Ruang Island were forced to evacuate to a nearby island.
This comparison pair of true-color images was acquired by the Moderate Resolution Imaging Spectroradiometer, flying aboard NASA’s Terra and Aqua satellites, on September 25. The top image was acquired by Terra MODIS at 1:55 UTC, while the bottom image was acquired by Aqua MODIS at 4:50 UTC. Notice how much the plume grew in that 3-hour span of time. (Note: the Aqua image appears noticeably different because the relative sun angle makes both the plume and the ocean surface appear much brighter.)
Images courtesy Jacques Descloitres, MODIS Land Rapid Response Team at NASA GSFC