Semisopochnoi volcano (Aleutian Islands, USA) - Smithsonian / USGS Weekly Volcanic Activity Report for 23 November-29 November 2022 (Continuing Activity)

On 7 November AVO stated that small explosions at the N crater of Mount Cerberus at Semisopochnoi had been detected in geophysical data during the previous week and volcanic tremor simultaneously resumed. Though ash emissions were not visually observed, the type of unrest was similar to previous periods associated with ash emissions below 3 km (10,000 ft) a.s.l.; the Aviation Color Code was raised to Orange (the second highest level on a four-color scale) and the Volcano Alert Level was raised to Watch (the second highest level on a four-level scale). Seismicity was low during 7-8 November, and clouds prevented webcam and satellite images. ... Read all

On 29 September AVO lowered the Aviation Color Code for Semisopochnoi to Yellow (the second lowest level on a four-color scale) and the Volcano Alert Level to Advisory (the second lowest level on a four-level scale) noting that no ash emissions or explosive activity had been detected since 14 September. Seismicity had decreased, though remained at elevated levels. Steam emissions from the active vent in the N crater of Mount Cerberus persisted. ... Read all