Alaska volcano yellow alert: Semisopochnoi eruption fears as scientists spot 'new unrest'

The Alaska Volcano Observatory has issued a yellow warning, which USGS indicates means: “Volcano is exhibiting signs of elevated unrest above known background activity.” High-resolution satellite images yesterday showed a small ash deposit coming from the North Cerebus Crater on the Semisopochnoi Island in Alaska

The steam has obscured views into the crater.

The Alaska Volcano Observatory said: “There is no evidence for continuing activity, but observation of a new deposit suggests renewed unrest.”

They added how they are “increasing the Aviation Color Code to yellow and the Volcano Alert Level to advisory”.

The Observatory continued: “Small eruptions producing minor ash deposits within the vicinity of the volcano are typical of activity during unrest at Semisopochnoi since September 2018, with the last detected activity in June 2020.

“Local seismic stations have been offline since November 11, 2020.

“New explosions could occur at anytime with no warning.”

The volcano is monitored remotely by satellite and lightning senors.

The Observatory added in their report: “An infrasound array on Adak Island could detect explosive emissions from Semisopochnoi with a 13 minute delay if atmospheric conditions permit.”

Semisopochnoi Island is part of the Rat Islands group in western Alaska and contains several volcanoes.

It is the largest young volcanic island in the western Aleutians and is composed of a number of volcanic landforms.

Mount Cerberus is the most active of three younger volcanos within the island.

Semisopochnoi’s last known eruptions took place in October 2018 and July 2019.

A historic eruption was reported in 1873, and at least four others may have occurred in the previous hundred years, but documentation is scant.

Back in December, geologists discovered that a trail of volcanic islands off the coast of the US state may actually be connected to one giant caldera.

The cluster of six volcanoes in the Aleutian Islands – known as the Islands of the Four Mountains (IFM) – may be connected to a much bigger underwater volcano.

Scientists analysed seismic activity, gas emissions, gravity measurements and geochemistry in the region surrounding the six stratovolcanoes of Carlisle, Cleveland, Herbert, Kagamil, Tana and Uliag – and their results suggested activity could be traced to a bigger source.

More to follow…

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