Peak of Anak Krakatau was brought down by more than 200 metres in explosion that triggered waves killing more than 420 people

This article is more than 1 year old

This article is more than 1 year old

Scientists say Indonesia’s Anak Krakatau volcano island, which erupted and collapsed a week ago triggering a deadly tsunami, is now only about a quarter of its pre-eruption size.

Anak Krakatau now has a volume of 40-70m cubic meters having lost up to 180m cubic meters since the 22 December disaster, according to Indonesia’s volcanology agency. The crater peak was brought down from 338 metres to 110 metres.

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The explosion caused a tsunami that hit Sumatra and Java where more than 420 people died and 40,000 were displaced.

Experts have largely relied on satellite radar images to work out what happened to the volcano because cloud cover, continuing eruptions and high seas have hampered inspections. The centre said it would get more precise results from more visual inspections.

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Authorities have warned residents to stay a kilometre away from the coastline of the Sunda Strait, which separates Java and Sumatra, because of the risk of another tsunami.

Experts say any further tsunami triggered by the volcano would be less severe due to its reduced mass. Anak Krakatau, which means Child of Kratakau, is the offspring of the infamous Krakatau volcano whose monumental eruption in 1883 triggered a period of global cooling.