Anak Krakatau History: Timeline of a Volcanic Rebirth

TEMPO.CO, Jakarta - Mount Anak Krakatau in the Sunda Strait is one of the world's most dynamic active volcanoes. Born from the sunken caldera of its famous parent volcano, Krakatau or Krakatoa, the "Child of Krakatoa" has spent nearly a century in a relentless cycle of destruction and reconstruction.

Citing from various sources including the Geological Agency of the Ministry of Energy and Mineral Resources (ESDM) and Center for Volcanology and Geological Hazard Mitigation (PVMBG), here is the year-by-year history of how Anak Krakatau emerged, grew, collapsed, and continues to rebuild itself.

Timeline of Mount Anak Krakatau

1883: The Cataclysmic Origin

The history of Anak Krakatau begins with the catastrophic eruption of ancient Krakatoa in August 1883. The explosion collapsed three volcanic peaks, namely Perbuwatan, Danan, and Rakata, creating a massive undersea caldera and triggering 30-meter tsunamis that killed over 36,000 lives. This collapse left a hollow magma chamber beneath the ocean floor where a new volcano would eventually form.

1927–1929: Undersea Birth

After 44 years of dormancy, underwater activity resumed at the base of the caldera. On December 29, 1927, submarine eruptions began ejecting jets of water and ash from a depth of 180 meters. Volcanic deposits gradually accumulated until a new crater wall broke through the ocean surface. Geological authorities officially designated June 11, 1929, as the birth date of the island named Anak Krakatau.

1931–1960: Early Growth and Lake Formation

The young volcano entered an intense building phase, recording at least 47 separate eruptions. During this era, seawater filled the crescent-shaped crater to form a lake, which was eventually sealed off and buried by eruptive deposits by 1961.

1992–2001: A Decade of Daily Eruptions

Beginning in November 1992, Anak Krakatau experienced one of its most active periods in modern history, erupting almost daily. Frequency during peak intervals reached up to one explosion every 15 minutes. This prolonged activity rapidly deposited lava and pyroclastic layers, expanding the island's coastline and elevation.

A historical study by the Geological Agency noted that during its active centuries, Anak Krakatau grew at an average rate of four meters per year, with eruption cycles typically occurring every one to six years followed by resting periods of one to eight years to build up internal pressure.

2007–2009: Increased Explosions and Lava Flows

The Center for Volcanology and Geological Hazard Mitigation (PVMBG) raised the alert status to Level III in October 2007. On November 9, 2007, the volcano recorded 182 individual eruptions in a single day, sending incandescent lava streams cascading down its slopes. Booming noises were heard at observation posts over 40 kilometers away.

2011–2012: Peak Seismic Activity

In October 2011, the Smithsonian Institution recorded a peak of 5,883 daily seismic events at the volcano. Subsequent eruptions in September 2012 pushed lava into the ocean, expanding the island's coastline by 100 meters and sending ash plumes 75 kilometers north to cover the city of Bandar Lampung.

2018: Peak Elevation, Flank Collapse, and Tsunami

By September 2018, Anak Krakatau reached its highest recorded elevation at 338 meters above sea level. However, continuous eruptive pressure led to a catastrophic flank collapse on December 22, 2018.

The massive underwater landslide triggered a devastating tsunami along Banten and Lampung. National Disaster Management Agency (BNPB) records show the disaster resulted in 437 deaths and displaced over 40,000 people, while the volcano lost two-thirds of its height, shrinking down to 110 meters.

2022–2023: Restructuring Phase

Following its structural collapse, Anak Krakatau entered a new construction cycle. Geological Agency data recorded multiple eruption series in 2022 and 2023, with ash columns reaching up to 1,000 meters above the crater rim. By late 2023, Magma Indonesia had logged at least 85 distinct eruptive events, signaling that the volcano was actively rebuilding its body.

September 2026: The Latest Escalation

Following a brief lull, Anak Krakatau reawakened in July 2026, before culminating in a severe eruptive phase starting September 4, 2026.

Meteorology, Climatology, and Geophysics Agency (BMKG) Head Teuku Faisal Fathani reported that ash clouds reached altitudes of up to 50,000 feet, drifting across five provinces and forcing the temporary shutdown of eight airports as the volcano continues its centuries-long cycle of physical regeneration.

Read: Was Krakatau's 1883 Eruption the Loudest Sound in the History?

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