The peak of Anak Krakatau was brought down by more than 200m after the flank collapse that triggered tsunami waves killing more than 420 about 10 days ago.
The Indonesian volcano that triggered a deadly tsunami when it erupted and collapsed on December 22, 2018, is now only a quarter of its previous size.
Scientists said Anak Krakatau now has a volume of 40-70 cubic metres, having lost up to 180m cubic metres of volume since the eruption on 22 December.
The centre said the crater peak was 110m high on December 28, 2018, compared to 338m in September.
The analysis from Indonesia’s Centre for Volcanology and Geological Disaster Mitigation demonstrates the power of the tsunami that crashed into 186 miles of coastline in Sumatra and Java.
More than 420 people died and 40,000 were displaced in the 2-meter-high tsunami waves created by Anak krakatau collapse.
Anak Krakatau, which means Child of Krakatoa, is the offspring of the infamous Krakatoa volcano whose monumental eruption in 1883 triggered a period of global cooling.