Fig. 1

Elevated volcanic activity prior to sector collapse. a Location of Anak Krakatau. Coastline map created using the GMT/MATLAB Toolbox⁵⁹. b Multiyear time series of the volcanic radiative power (VRP) and cumulative volcanic radiative energy (VRE) recorded as MODIS data at Anak Krakatau. A sharp increase in thermal activity started on 30 June 2018, marking the beginning of a new eruptive phase that culminated in the collapse of the edifice on 22 December 2018. The red rectangle marks the recent eruptive period shown in detail in Fig. 3. c Time-averaged discharge rate (TADR) derived from satellite thermal data during the June–Dec 2018 eruption. Note the occurrence of 11 pulses with a TADR above 3 m³ s⁻¹ (dashed line) associated with effusive paroxysms that produced lava flows. The cumulative erupted volume (red line) indicates a gradual decline in effusive activity after Oct 2018