Mount Anak Krakatau’s roughly 25- hour continuous eruption ended in the early hours of September 6, 2026, but the volcano remains highly active at Alert Level III with a high chance of further eruptions.

The continuous phase began late on September 4 (around 11:07 p.m. local time) and ended around 12:04 a.m. on September 6. Activity has since returned to its more typical intermittent Strombolian pattern, with black ash columns reaching up to about 300 meters above the summit.

Monitoring from September 6- 7 recorded dozens of earthquakes (including 93 low- frequency and 98 hybrid/multiphase events), plus other eruption- and emission-related seismic signals.

PVMBG (the Volcanology and Geological Hazard Mitigation Center) has kept the 3 km exclusion zone in place around the activity center.

Potential hazards if continuous activity resumes include incandescent rock fragments, heavy ashfall, hot clouds (pyroclastic flows), and lava flows.

Residents, tourists, and shipping are barred from the zone.

There is currently no tsunami threat from the ongoing activity (unlike the 2018 Sunda Strait tsunami, which was triggered by flank collapse rather than the eruption itself). Officials have urged coastal residents in Banten and Lampung to stay calm and rely on official updates.

Volcanologists note that frequent eruptions are normal for this young, still- building volcano as material accumulates and the edifice grows.

As long as the system remains open, major energy buildup is not necessarily indicated. The agency continues round- the- clock visual and instrumental monitoring and will reassess the alert level if conditions change significantly.

The dramatic night photo (glowing red lava/plume against a dark sky, with bright jagged streaks that appear to be volcanic lightning) matches the kind of imagery reported from the event, including views from Pasauran, Serang Regency, Banten, around September 5. Volcanic lightning is common in ash -rich eruptions due to charge separation in the plume.

This YouTube video (“The World’s Most Feared Volcano Just Roared Back To Life – And It’s Terrifying,” by the channel Breakpoint, uploaded around September 6, 2026) is a ~25- minute documentary- style overview of the recent Anak Krakatau activity.

The eruption: Late on September 4, 2026, Anak Krakatau produced a powerful pulse that drove an ash column to roughly 15 km (about 50,000 ft) into the lower stratosphere in roughly half an hour. Satellite advisories showed rapid escalation (from ~7,000 ft to ~45,000- 48,000 ft). The plume was pulsed rather than a single blast, with layered ash drifting in different directions. Lava fountaining, volcanic lightning, continuous rumbling, and reports of unusually large waves in the Sunda Strait were noted.

Monitoring context: Continuous volcanic tremor (a sustained ground “hum” indicating magma and gas movement) is highlighted as the critical signal that the system is still being fed. Indonesia’s geological agency had already described shallow magma dynamics as “very high” in the preceding period, with numerous tremor episodes, eruption earthquakes, and hybrid quakes. The volcano has been at Alert Level III since July.

Aviation impact: Ash at cruising altitudes prompted rapid SIGMETs and Darwin VAAC advisories because the plume crossed a major Southeast Asian flight corridor. Ash is treated as a serious aircraft hazard (it can melt in jet engines).

Historical backdrop: The video recounts the 1883 Krakatoa catastrophe (loudest recorded sound, massive death toll) and the 2018 flank- collapse tsunami generated by Anak Krakatau itself (a largely silent, no- warning event). It stresses that water- related hazards (waves, possible instability) remain a key concern even when the ash plume is the most visible feature.

Outlook discussed: Whether this is a short- lived spike or the start of a longer eruptive cycle; why the official alert level has not been raised further; the potential for continued activity while the magma system remains open; and broader questions (size relative to past events, any climate/cooling effect, what to watch next).

The video draws on sources such as VAAC advisories, Indonesian agency reports, Tempo, The Watchers, and scientific papers on the 2018 collapse/tsunami. It ends by framing the situation as ongoing rather than resolved.

This aligns with the Jakarta Globe reporting and related coverage: the intense continuous phase lasted about 25 hours (ending early on September 6), activity has shifted back toward intermittent Strombolian behavior, the volcano remains at Level III with a 3 km exclusion zone, seismic activity is still elevated, and there is currently no tsunami warning, though close monitoring continues.

2018 Anak Krakatau event vs. the September 2026 activity

The 2018 event (22 December 2018)

Primary mechanism: A major lateral/sector collapse (flank failure) of the southwestern side of the volcano during ongoing eruptive activity. Roughly 0.1- 0.3 km³ of material (estimates vary by study; many cluster around 0.2 km³) slid into the deep caldera to the southwest.

Tsunami generation: The sudden displacement of seawater by the landslide produced the tsunami. Waves reached nearby coasts of Java (Banten) and Sumatra (Lampung) in about 30 minutes. Near- field run- ups on islands around the volcano reached tens of meters (locally >80 m vegetation stripping); far- field coastal run-ups were typically up to ~13 m.

Impacts: Approximately 437 deaths, ~14,000 injured, and tens of thousands displaced. Damage was concentrated along the Sunda Strait shores. The event occurred with little effective public warning because the collapse produced only modest short-period seismic signals.

Volcano change: Pre- collapse height was roughly 320- 338 m. The collapse “decapitated” the cone, dropping the height to around 110-120 m and removing a large fraction of the subaerial volume. Activity then shifted to more explosive phreatomagmatic (water-influenced) eruptions as seawater interacted with the open conduit.

Context: This followed months of elevated activity in 2018. Scientists had previously identified the southwest flank as potentially unstable due to the volcano’s position on the steep edge of the 1883 caldera.

Key differences with the September 2026 activity

Indonesian geological authorities (PVMBG / Badan Geologi) have repeatedly stressed that the situations are not equivalent:

Mechanism: 2026 activity has been dominated by eruptive processes (continuous phase lasting ~25 hours, ash columns reaching up to ~15 km in pulses, lava fountaining, volcanic lightning, elevated continuous tremor and hybrid earthquakes). There has been no reported large-scale flank collapse or significant landslide into the sea.

Morphology and volume: After the 2018 collapse, the volcano has been rebuilding, but the new edifice is still relatively small. Officials state that the current growth has not reached a critical volume or height that would make another large sector collapse likely. The pre- 2018 unstable configuration no longer exists in the same form.

Tsunami risk assessment: Authorities have explicitly said the current eruptions are not generating a tsunami and that the potential for a 2018- style landslide- triggered tsunami is low at present. Coastal residents in Banten and Lampung have been advised to remain calm and rely on official information. A 3 km exclusion zone remains in place mainly for ballistic ejecta, ash, and possible pyroclastic or lava hazards.

Alert and monitoring: The volcano has been held at Level III (Alert) with continuous instrumental and visual monitoring. Elevated tremor indicates magma is still moving, so further eruptions remain possible, but the primary concern right now is ash (aviation disruption, health impacts) rather than sudden flank failure.

Summary comparison

Aspect	2018	September 2026
Main hazard driver	Flank collapse → tsunami	Eruptive ash columns, tremor, possible ongoing Strombolian activity
Tsunami generated?	Yes (landslide- driven)	No (official assessment)
Height / volume context	Tall, unstable SW flank (~320–338 m)	Smaller rebuilt cone; critical collapse volume not reached
Casualties / impact	~437 deaths, major coastal damage	Ash-related disruption (flights, health); no tsunami casualties
Official stance	Post-event recognition of collapse risk	Explicitly different morphology; low collapse/tsunami potential now

The video highlights the 2018 event as the reason local communities are especially sensitive to any reports of unusual waves, even though the current dominant hazards are atmospheric (ash plume height, aviation, respiratory issues). Ongoing monitoring focuses on both eruptive intensity and any signs of renewed flank deformation.