Rabaul is a large caldera volcano whose eastern rim has been breached and flooded by the Bismark Sea, evidenced by Great Harbor seen in the image to the right.

Numerous vents and cones occur around the rim, including Tavurvur Cone, which was erupting when this image was captured by the Advanced Land Imager on NASA’s Earth Observing-1 (EO-1) satellite on November 30, 2009.

From November 20–26, strong eruptions from Tavurvur shot ash plumes 1 mile into the air above the summit and “showered the flanks with lava fragments that were incandescent at night,” according to a report from the Rabaul Volcano Observatory.

A caldera volcano forms when a massive eruption empties the magma chamber underlying the volcano; the overlying rock and debris sink into the chamber, leaving a crater at the surface. The eruptions that formed Rabaul Caldera took place as recently as 3,500 and 1,400 years ago.

The 1994 eruption that buried Rabaul involved the currently active Tavurvur Cone as well as Vulcan Cone, located across Blanche Bay to the southwest (not pictured). The city of Rabaul is located on the peninsula across the Great Harbor from Tavurvur.

More than a foot of ash fell on parts of the city, and combined with rain, it collapsed many of the small city’s buildings and houses.

Full story and image: NASA