Explosive Eruptions Continue to Rock Alaska's Bogoslof Volcano

A plume rises from Bogoslof volcano, partially obscured by a mountain on Unalaska Island, on Wednesday, Dec. 21, 2016.Lynda Robinson/AVO A few updates on volcanic eruptions at the start of 2017: Alaska The biggest volcanic news of the last month has been the surprising and vigorous eruptions at Bogoslof in the Aleutians of Alaska. After producing a large explosive eruption on December 16, the volcano has followed up by adding more explosions every day or so, many of which reached 5 to 10 kilometers (15,000-35,000 feet) over the small island. Just yesterday (January 4), the volcano produced another explosion that reached 10 kilometers (33,000 feet). The highly explosive nature of these eruptions is likely rooted in the interaction between the new magma reaching the surface and the abundant seawater it meets when it erupts. That water can quickly flash to steam and help fragment the magma into ash, adding to the explosivity of the eruption. The Alaska Volcano Observatory has released a preliminary map (see below) that show the changes to the island, where these explosive eruptions have destroyed part of the previously existing island and added more land, mainly in the form of volcanic debris from these blasts. AVO currently has Bogoslof on a Red/Warning alert status because of the unpredictable nature of these towering explosive shots, many of which have been obscured by clouds. Instead, evidence of eruptions from Bogoslof has been picked up either by seismometers on distant volcanoes (like Alaska's Okmok) or via infrasound that detects low frequency sounds from explosion over very long distances (100s to 10,000s of kilometers).