AVO reported that during 31 March-1 April clear satellite and web camera images of Veniaminof showed no signs of emissions. On 2 April the Volcano Alert Level was lowered to Advisory and the Aviation Color Code was lowered to Yellow. Satellite data showed elevated surface temperatures, especially over the flank-vent lava flows through 4 April. Low-level ash emissions were recorded by the webcam on 5 April, prompting AVO to raise the Volcano Alert Level and Aviation Color Code to Watch and Orange, respectively. Tephra deposits were visible to the SE.

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.

Source: US Geological Survey Alaska Volcano Observatory (AVO)