In eastern Siberia, a perfect circle of rock contrasts with the surrounding topography. The 6-kilometer- (3.7-mile-) wide ring looks like an impact crater, or the caldera of an extinct volcano, but it is neither. Kondyor Massif was formed by the intrusion of igneous, or volcanic, rock that pushed up through overlying layers of sedimentary rock, some of them laid down more than a billion years ago.
Published May 25, 2008
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.
Published Mar 28, 2007
Acquired December 1, 2012, these images provide natural- and false-color views of restless Tolbachik Volcano.
Published Dec 8, 2012
