BRIN Says Anak Krakatau’s Thick Ash Could Reach Several Countries

Anak Krakatau’s eruption sent a thick, dark plume high above the Sunda Strait, prompting concern that volcanic material could travel beyond Indonesia. BRIN senior researcher Erma Yulihastin estimated the column at 13 kilometers, nearly reaching the tropopause.

“If it is detected as brown at this intensity by satellite even though it is over the ocean, that means the eruption is quite thick,” Erma said in a post on X on Saturday. She said the plume should be anticipated by the Indonesian government and neighboring countries.

Erma warned that material reaching the tropopause could be carried farther by the Hadley circulation. That circulation, she said, can transfer emissions from equatorial areas toward subtropical countries.

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If it is detected as brown at this intensity by satellite even though it is over the ocean, that means the eruption is quite thick. The column is estimated at 13 kilometers, which has already penetrated almost to the tropopause.

Residents near the volcano also reported the eruption’s effects. Fauzan, from Kampung Baru in Pandeglang’s Labuan district, said his house door began shaking at about 1 a.m. Saturday and continued vibrating into the morning. A video he shared showed the door shaking as if someone were trying to force it open.

The eruption produced rumbling sounds and lava fountains. Anak Krakatau remains at Alert Level III, and people have been told not to conduct activities within 3 kilometers of the active crater. A six-hour observation report from Indonesia’s Volcanology and Geological Hazard Mitigation Center said the weather was cloudy, with weak to moderate winds blowing northwest. The volcano was visible before becoming obscured by fog, while no crater smoke was observed in that reporting period.

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A column reaching the tropopause is dangerous because the Hadley circulation can transfer what is ejected in the equatorial region to subtropical countries.