• Semisopochnoi Aviation Color Code raised to Orange, Alaska

    The Alaska Volcano Observatory (AVO) has raised the Aviation Color Code for Semisopochnoi volcano to Orange and the Volcano Alert Level to Watch on July 12, 2021. The decision was made due to the onset of continuous volcanic tremors and detections of explosive…

  • First significant explosion at Great Sitkin since 1974, Alaska

    A short-lived explosive eruption began at Great Sitkin volcano, Alaska at 05:04 UTC on May 26, 2021, and lasted for about 1 to 2 minutes. The Aviation Color Code was raised to Red at 05:30 UTC. This was the first significant explosion at the volcano since 1974. The…

  • Renewed unrest at Semisopochnoi, alerts raised, Alaska

    High-resolution satellite imagery acquired on February 6, 2021, showed a small ash deposit extending less than 3 km (1.8 miles) to the north from North Cerebus Crater on Semisopochnoi Island, Alaska, U.S. Steam emissions obscured views into the crater, the Alaska…