Okmok volcano began erupting in mid-February, 1997. Okmok is on Umnak Island, in the eastern Aleutian Islands, about 75 miles west-southwest of Dutch Harbor. The first sign of heightened activity was a "hot spot" observed by AVO scientists, on satellite images taken at 5:00 and 10:30 am AST on February 13, 1997.

Later on February 13, observers at the former Fort Glenn military base, 10 miles east of the volcano , reported seeing a dark ash plume at about 10 am AST rise above the caldera rim to an altitude of about 5,000 feet ASL where prevailing winds carried it to the southwest. Later reports from on-site observers suggest that the eruption began at least a few days before February 13.

Okmok Volcano

The Fox Islands

The eastern Aleutian Arc

53° 24' N 168° 10' W caldera rim elevation 3520 feet (1,073 m) elevation of erupting cone about 2500 feet (760 m)

This image was obtained on February 18 and shows several square kilometers of hot ground - presumably incandescent lava.

This image from March 10 shows the largest hotspot ever seen by AVO. There are 34 hot pixels, 18 of which have saturated the satellite's temperature sensor. Hot pixels are white on the image. Each pixel is one square kilometer. Saturated pixels record ground temperatures above 50 degrees centigrade averaged over the entire pixel. This image suggests that there is fresh lava covering about half the caldera floor.

Synthetic Aperture Radar image of Okmok from before the current eruption. Image courtesy of the Alaska SAR Facility. Photo mosaic of current Okmok activity taken on Feb. 28, 1997 by John Sease (NOAA). The active cone is against the rear caldera wall. The 1997 lava flow (black) extends around the back and right-hand side of another post-caldera cinder cone in the foreground.

Closer view of the 1997 Okmok lava flow (courtesy of John Sease, NOAA). The view is to the southwest with the shoulder of post-caldera Cone D in the foreground, the active lava flow in right foreground, and the erupting post-caldera Cone A in the background. Recheshnoi and Vsevidof Volcanoes on southwestern Umnak Is. are in the far distance.