Eruption at Shishaldin volcano, ash cloud to 7.3 km (24 000 feet) a.s.l., Alaska

Eruption at Shishaldin volcano, ash cloud to 7.3 km (24 000 feet) a.s.l., Alaska

A new eruption is taking place at Shishaldin volcano, Alaska on January 3, 2020, with ash cloud rising to 6 - 7.3 km (20 000 - 24 000 feet) above sea level at 21:00 UTC, drifting E-SE.

According to Alaska Volcano Observatory, the level of seismicity has increased to moderate levels and several pilot observations of ash clouds have been reported to AVO.

The ash cloud is visible in satellite data and extends 24 - 32 km (15-20 miles), southeast of the volcano.

Shishaldin remains at Aviation Color Code ORANGE and Alert Level WATCH. The National Weather Service has issued SIGMET to 7.3 km (24 000 feet) above sea level.

According to GOES-West satellite imagery, the eruption started at around 19:00 UTC.

The image below was captured on January 2, 2020, by Sentinel-2:

Credit: Copernicus EU/Sentinel-2 - Natural SWIR / Antonio Vecoli / AdamPlatform

Geological summary

The beautifully symmetrical volcano of Shishaldin is the highest and one of the most active volcanoes of the Aleutian Islands. The 2857-m-high (9 379 feet), glacier-covered volcano is the westernmost of three large stratovolcanoes along an E-W line in the eastern half of Unimak Island.

The Aleuts named the volcano Sisquk, meaning "mountain which points the way when I am lost." A steady steam plume rises from its small summit crater. Constructed atop an older glacially dissected volcano, it is Holocene in age and largely basaltic in composition.

Remnants of an older ancestral volcano are exposed on the west and NE sides at 1 500 -1 800 m (4 920 - 5 900 feet) elevation. There are over two dozen pyroclastic cones on its NW flank, which is blanketed by massive aa lava flows.

Frequent explosive activity, primarily consisting of strombolian ash eruptions from the small summit crater, but sometimes producing lava flows, has been recorded since the 18th century. (GVP)

Featured image credit: Copernicus EU/Sentinel-2 - Natural SWIR / Antonio Vecoli / AdamPlatform. Acquired January 2, 2020.

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