Semisopochnoi volcano (Aleutian Islands, USA) - Smithsonian / USGS Weekly Volcanic Activity Report for 15 March-21 March 2023 (New Activity / Unrest)

AVO reported that low-level ash emissions from the N crater of Semisopochnoi's Mount Young were observed in several web camera images during 18-19 March. Small explosions and volcanic tremor had also resumed. Ash emissions were not detected in satellite images, though on 18 March a robust steam-and-gas plume was visible drifting 150 km from the N crater.
AVO raised the Volcano Alert Level to Watch (the second highest level on a four-level scale) and the Aviation Color Code to Orange (the second highest color on a four-color scale) on 19 March. Low-level seismicity continued during 20-21 March and one small explosion was detected in seismic and infrasound data. Clouds obscured webcam and satellite views.

Source: US Geological Survey Alaska Volcano Observatory (AVO)
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From: Global Volcanism Program, 2023. Report on Semisopochnoi. In: Mayberry, G (ed.), Weekly Volcanic Activity Report 15 March-21 March 2023. Smithsonian Institution and US Geological Survey.