Alaska Volcano’s Week-Long Eruption Eases After Massive Ash Cloud Emission

Warnings were issued to pilots due to the immense size of the ash cloud produced by an ongoing eruption of a remote volcano in Alaska’s Aleutian Islands on Tuesday.

The Alaska Volcano Observatory reported that the morning eruption of Shishaldin Volcano produced an ash cloud reaching approximately 5.5 miles (8.9 kilometers) in height. However, by early afternoon, the ash emissions had decreased to below 1.9 miles (3 kilometers), leading to the downgrade of the aviation alert.

Impact on Unimak Island and False Pass Community

Shishaldin Volcano, located approximately 700 miles (1,127 kilometers) southwest of Anchorage on Unimak Island, experienced eruptions starting from July 11. The island’s small community of False Pass, with around 65 residents, is situated about 25 miles (40 kilometers) northeast of the volcano.

On July 11, a U.S. Coast Guard overflight confirmed the eruption of lava within the summit crater. Subsequently, on Friday, there was a significant explosion resulting in an ash cloud that reached up to 7.5 miles (12 kilometers) and moved southward over the Pacific Ocean. Later on the same day, a smaller explosion occurred.

Shishaldin Volcano’s High Activity Level and Ash Cloud Formation

The volcano is known to be one of the most active in the Aleutian arc. Initially, there were increased lava eruptions after midnight on Tuesday, but without significant ash emissions, as stated by the observatory. However, the situation changed later in the day when the ash cloud formed, leading the National Weather Service to issue an advisory due to the ash’s drift.

Volcanic ash, known for its angular and sharp particles, has practical applications as an industrial abrasive. However, when in a powdered form, it can be detrimental to jet engines, causing shutdowns.

Shishaldin’s Geological Characteristics and Crater Activity

The observatory describes Shishaldin as a symmetric cone with a base diameter of 10 miles (16 kilometers). The volcano’s funnel-shaped crater, which measures 660 feet (210 meters), frequently emits steam and occasionally releases small amounts of ash.

Throughout its history since 1824, Shishaldin Volcano has experienced at least 26 confirmed eruptions. While most of them were relatively minor, a significant eruption occurred in 1999, generating an ash cloud that extended up to 8.5 miles (14 kilometers).

Read the original article: Phys Org

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