Ecuador's volcano Tungurahua has been particularly active this week, spewing ash up to 23,000 feet (7 kilometers), putting on a fiery light show, and rumbling with at least 70 measurable explosions. Ash has dusted the region and some localized pyroclastic flows—masses of hot rock and gas—have been seen. Volcanic blocks have been tossed up to a kilometer away.

The volcanologists on the scene say this relatively moderate eruption may continue for some time, and it's possible it could build into something bigger (and potentially life threatening). (See more pictures of Tungurahua erupting in the recent past.)

Tungurahua lies about 84 miles (135 kilometers) southeast of the capital city of Quito. The 16,475-foot (5,023-meter) volcano has been erupting intermittently since October 1999. Tungurahua means