Mount Okmok and Okmok Caldera, in Alaska, USA53.4N 168.1W
This orthorectified image shows the wide, circular Okmok Caldera, which truncates the top of a large shield volcano. The highest point on the caldera rim is called Mount Okmok. Both are located in the northeastern part of Umnak Island in the eastern Aleutian Islands of Alaska, USA.
Although the last major eruptions of Okmok—with an estimated VEI strength of 6—occurred 8,300 and 2,400 years ago, on Saturday, July 12, 2008, Okmok Caldera exploded without warning, sending a plume of ash over 33,000 feet (10,000 m) into the air. No lava flow was reported, though the volcano has issued flows in the past.
Before then, the volcano had last erupteded in 1997 and produced a lava flow, once again erupting with no initial warnings. Residents of Fort Glenn, a nearby ranch, fled from falling ash and volcanic rock.