Short report on the Krakatau expedition in August 2019
The steaming crater lake of Anak Krakatau
Erosion canyons formed by rainfall
Shore of the crater lake
Between 15 and 17 August 2019 a small expedition group guided by Andi visited the Krakatau Caldera to study the huge changes after the partial collapse of Anak Krakatau in December 2018.
On 16 August we entered Anak Krakatau and climbed up from the northeast to the upper rim across ash fields and a landscape of canyons caused by erosion. From there we observed the impressive boiling crater lake. Later we entered Anak once more: Our boat stopped in front of the crater open to the seaside (water temperature of the Krakatau Caldera near Anak Krakatau: 38,8°C).
Stefan and me cautiously approached the crater lake – always in danger of unpredictable phreatomagmatic eruptions. The area west of the crater lake was rather hot ( soil temperature at a depth of 4 cm partly 68°C), partly muddy , covered with tephra and partly with sulfur deposits. It was a little bit alarming to see some clearly visible long fissures in the soil . I measured the temperature of the crater lake: It was between 61°C and 62°C at the edge of the lake, but might be at least 80°C in other places of the lake. The ph-value measured by Stefan was between 0,2 and 1.
I thank Volcano Discovery and our guide Andi for the excellent organisation of this impressive expedition!
Text & images: Anke Reimer - Volcanedo.de
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