These true-color images show a wadi in northern Niger on September 19, 2007, and September 18, 2009. The 2007 shows the wadi populated by plants that have taken advantage of recent precipitation.
Using data acquired September 13, 2002, this 3-D visualization shows an old lahar (avalanche of volcanic mud) extending from Anyuyskiy Volcano in far eastern Russia.
The approximately 4-kilometer-wide Dendi Caldera includes some of this silica-rich volcanic rock: the rim of the caldera, visible in this astronaut photograph, is mostly made of poorly consolidated ash erupted during the Tertiary Period (approximately 65–2 million years ago).
Acquired October 20, 2009, this high-resolution image of Chaitén Volcano shows a volcanic plume that appears almost white near the summit, likely due to high water content.
Lahars present an ongoing threat to those living around New Zealand’s Mount Ruapehu. On March 18, 2007, one such slurry burst out of Mount Ruapehu’s caldera and flowed down the side of the volcano.