Yesterday afternoon, around 16:30 UTC (08:30 local time), an explosive eruption of the volcano Shishaldin began. It was preceded by several hours of increasing seismic activity. The explosion produced a large ash cloud that rose to an altitude of 9,700 meters and drifted southeastward over the sea. During the eruption, a high thermal radiation of 321 MW was recorded, indicating that not only volcanic ash but also red-hot lava was erupting. The eruption caused strong tremors, clearly visible on the seismogram.
Half an hour later, seismic activity rapidly decreased, and the altitude of ash emissions observed by satellite also reduced to about 4,500 meters. By 20:00 UTC, the ash cloud had spread about 125 km in low altitude.
Shishaldin is a 2,857 m high stratovolcano on the Aleutian Island of Unimak. The Aleutians are a volcanic island arc connected to the Alaska Peninsula.