Gunung Anak Krakatau has entered a dramatic chapter of geological recovery, with satellite data confirming its landmass has officially surpassed its size prior to the catastrophic eruption and collapse of December 2018. Located in the Sunda Strait between the provinces of Lampung and Banten, the volatile volcanic island now spans approximately 341.5 hectares following a sustained series of eruptions in early September 2026.
The Anatomy of Growth Following the 2018 Collapse
The transformation of Gunung Anak Krakatau illustrates the relentless dynamism of subsea volcanic systems. On December 22, 2018, a massive sector collapse of the volcano’s southwest flank triggered a devastating tsunami along the coasts of Banten and Lampung. That disaster sheared away the bulk of the cone, plunging the total land area down to a skeletal 246.18 hectares by December 26, 2018, sharply reducing its peak height from 330 meters down to 120 meters.
According to data from the Geological Agency’s Center for Volcanology and Geological Disaster Mitigation (PVMBG), recent activity has reversed that contraction entirely. Sentinel satellite imagery from August 8, 2026, placed the island’s footprint at 312.3 hectares. Following continuous eruptive episodes between September 4 and September 6, 2026, fresh sediment accumulation pushed the land area up to 341.5 hectares by September 15, adding roughly 32.8 hectares of new volcanic deposits.
Rita Susilawati, head of the PVMBG at the Ministry of Energy and Mineral Resources, noted the stark contraction caused by the historical disaster, pointing out how the sudden loss of mass fundamentally altered the volcano’s mechanics. The abrupt influx of seawater into the newly exposed crater initially forced a shift from gentle Strombolian explosions to explosive Surtseyan activity.
A Collaborative Scientific Consensus on the Rebuilding Phase
This physical expansion is not an isolated phenomenon, but part of a well-documented trajectory. Collaborative research involving the National Research and Innovation Agency (BRIN), the University of Birmingham, the Institut Teknologi Bandung (ITB), Penn State University, the British Geological Survey, and the University of Oxford confirms that Gunung Anak Krakatau is deeply entrenched in a natural rebuilding phase.
Dini Nurfiani, a researcher at BRIN’s Geological Disaster Research Center, explained that the volcano’s history follows a predictable cycle of growth, eruption, collapse, and subsequent cone regeneration. Since 2019, the eruptive style has transitioned back toward Strombolian outbursts, persistent lava fountains, and fresh lava flows that actively armor and thicken the post-collapse crater floor.
Asymmetrical Expansion and Long-Term Stability Risks
Despite the rapid accumulation of material, researchers emphasize that the growth of Gunung Anak Krakatau remains distinctly asymmetrical. The southwestern sector builds upward along a steep underwater caldera slope, whereas the northeastern flank rests on a much shallower seabed foundation.
This structural imbalance—characterized by heavy, dense layers of solid lava resting atop porous, fragile tuff deposits on steep gradients—creates persistent structural vulnerabilities. Volcanologists continue to monitor these shifts closely, utilizing continuous seismic equipment, visual tracking, and satellite payloads to evaluate slope stability and guard against future sudden collapses that could once again threaten coastal settlements in the Sunda Strait.
