The northeastern slopes of Big Ben volcano on Heard Island are visible in shadow at the top right of this photo. Mawson Peak (small circle in the upper center of the image), sits within a breached caldera (collapsed and empty magma chamber beneath a volcano) on the southwestern side of the volcano - the shadow cast by Mawson Peak points directly to the crescent-shaped caldera rim. This image, taken during the Southern Hemisphere summer, also shows the dark brown volcanic rock that forms the island. The southwest-pointing tongue of ice is Gotley Glacier. Image credit: NASA.
In October 2012, satellites measured subtle signals that suggested volcanic activity on remote Heard Island. These images, captured several months later, show proof of an eruption on Mawson Peak. By early April 2013, Mawson's steep-walled summit crater had filled, and a trickle of lava had spilled down the volcano's southwestern flank. Image courtesy of NASA.
This image shows vortex shedding occurring as winds pass Heard Island (in the lower left) resulting in a Kármán vortex street - a repeating pattern of swirling vortices - in the clouds. Photo courtesy of NASA.