Mount Anak Krakatau erupted overnight into Saturday, spewing rocks and volcanic ash into the air, according to the country’s Geological Agency. The ongoing eruption follows a period of heightened activity that began on July 2, when local authorities raised the volcano’s alert status to Level III, as reported by local media outlet Tempo.
As of September 5, 2026, at 4:40 am Western Indonesian Time, the eruption remains active. According to the Geological Agency, rumbling can still be heard from the Krakatau Pasauran PGA Post, and the event has continued.
Seismic Activity and Eruption Patterns
MAGMA Indonesia, a digital platform that provides real-time information about geological hazards across the country, recorded seismic activity linked to the eruption starting Friday morning. A seismograph registered a maximum amplitude of 33 millimetres with a duration of 14 seconds. Three more eruptions occurred Friday morning, followed by a lull before another series late on Friday.
The Geological Agency recorded six eruptions through 12:01 am local time Saturday (2201 PKT Friday). While the exact height of the eruption column was not observed, the bright red colour of the eruption plume was clearly visible. Officials described the activity as resembling a “lava fountain” that produces lava flows, noting that continuous eruptions lasting several hours are common.
Regional Impact and Tsunami Assessment
Residents across parts of West Java, Banten, and Lampung reported hearing booming sounds and feeling vibrations at the same time as Anak Krakatau’s activity. The Geological Agency stated that these phenomena are suspected to be related.
Despite the ongoing activity, the agency confirmed that the volcano’s growth since the December 22, 2018, eruption remains relatively small. Officials stated there is no potential for a collapse large enough to trigger a tsunami.
Did You Know? Frequent seismic events occur across Indonesia, which is positioned along the volcanic and fault-heavy Pacific “Ring of Fire.”
Geological Context and Future Outlook
According to Tempo, a local media outlet, eruptions at the volcano have persisted since the Level III alert status was declared on July 2. Continuous eruptions lasting several hours are common.
The Geological Agency stated that the activity bears a likeness to a “lava fountain” generating lava flows, while also noting that multi-hour continuous eruptions happen frequently going forward.
Expert Insight: Real-time seismic data compiled by the national geological hazards platform MAGMA Indonesia showed tremors tied to the eruption beginning Friday morning, with seismograph readings showing a 14-second duration and a peak amplitude of 33 millimetres.
Frequently Asked Questions
When did the latest eruption phase begin?
Coverage by local news provider Tempo noted that the volcano has kept erupting ever since its alert level was upgraded to Level III on July 2.
Is there a risk of a tsunami from the current activity?
Pointing out that the volcano has expanded only minimally since December 22, 2018, the Geological Agency asserted that any risk of a tsunami-causing collapse is absent.
Where were vibrations and booming sounds reported?
The Geological Agency reported gathering accounts of rumbling noises and ground motion across Banten, Lampung, and parts of West Java that coincided with Anak Krakatau’s activity and are believed to be connected.
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