On 4 August an eruption dropped a very light dusting of fine ash on Port Heiden . . . but no widespread ashfall has been reported since. During the week of 21-26 November residents 23 miles SE of Veniaminof reported vigorous steaming over the volcano. Poor weather for most of the interval from late November through mid-December prevented observers in Port Heiden from viewing Veniaminof; and during the same interval the NWS saw no evidence of volcanic activity at Veniaminof on satellite images.

Geological Summary. Veniaminof, on the Alaska Peninsula, is truncated by a steep-walled, 8 x 11 km, glacier-filled caldera that formed around 3,700 years ago. The caldera rim is up to 520 m high on the north, is deeply notched on the west by Cone Glacier, and is covered by an ice sheet on the south. Post-caldera vents are located along a NW-SE zone bisecting the caldera that extends 55 km from near the Bering Sea coast, across the caldera, and down the Pacific flank. Historical eruptions probably all originated from the westernmost and most prominent of two intra-caldera cones, which rises about 300 m above the surrounding icefield. The other cone is larger, and has a summit crater or caldera that may reach 2.5 km in diameter, but is more subdued and barely rises above the glacier surface.

Information Contacts: AVO.