The Indonesian volcano which triggered a deadly tsunami when it erupted and collapsed a week ago has shrunk to about a quarter of its previous size, scientists have said.
Indonesia's Centre for Volcanology and Geological Disaster Mitigation said Anak Krakatau now has a volume of 1.4 billion 2.4bn cubic feet, having lost 5.2bn to 6.3bn since the eruption on December 22.
The centre's analysis shows the scale of the island’s collapse, shedding light on the power of the tsunami that crashed into more than 186 miles of coastline in Sumatra and Java.
More than 420 people died in waves towering up to 6.6ft, while 40,000 others were forced to flee their homes.
The centre said the crater peak was 360ft high on Friday compared to 1,108ft in September.
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. More precise results will follow from more visual inspections.
Authorities have warned residents to stay at least a mile away from the coastline of the Sunda Strait, which separates Java and Sumatra, because of the risk of another tsunami.
But experts now say another potential tsunami triggered by the volcano collapsing again 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.