Raised again: Anak Krakatau returns to Level III (Siaga) on 9 October, with a 5 km exclusion zone, after 14 eruptions in four days

Safety & SecurityUpdatedUpdated: October 12, 2026

Our other articles on this crisis track airport closures and reopenings, the missing-journalists search, and earlier health/ashfall guidance — this entry is a standing, dedicated log of the volcano's own activity. The alert has now gone back up. After eight discrete eruptions on 6–9 September and no further eruption through 20 September, Badan Geologi lowered Anak Krakatau from Level III (Siaga) to Level II (Waspada) on 21 September at 18:30 WIB, with the exclusion radius cut from 3 km to 2 km. Activity then rose again from early October: Badan Geologi counted 14 eruptions from 6 to 9 October, and at 21:00 WIB on Friday 9 October it raised the volcano back to Level III (Siaga). The exclusion zone is now 5 km around the crater, plus 1 km around the new island-like mounds to its northwest and southeast. The Anak Krakatau monitoring post counted 26 eruptions in a 24-hour window, reported on 10 October, though visual observation was limited because some cameras were down and no ash column was observed; BMKG's satellite analysis showed ash dispersal up to about 6,000 ft (1.8 km) toward the west over part of the western Sunda Strait. Disaster expert Daryono of IABI said the raise is a step towards vigilance, not a reason to panic. We found no airport closure, NOTAM, or ferry disruption reported for 9–12 October. We will keep updating this log independently of the other articles, since the volcano itself is what determines whether the underlying hazard has actually passed.

Timeline

2 Jul 2026
Badan Geologi / PVMBG raises Anak Krakatau to Level III (Siaga) and sets a 3 km exclusion radius around the crater for residents, visitors, fishermen and climbers. More than 240 eruptions are recorded between then and 5 September.
Fri 4 Sep, 23:07 WIB
A continuous eruption begins, with booms and rumbling audible from the Pasauran observation post in Serang and reported across Banten, Lampung and West Java. The seismograph records a single eruption tremor of 70 mm amplitude lasting 21,600 seconds (six hours) — the strongest activity since the alert was raised. PVMBG interprets it as a lava fountain producing lava flows.
Sat 5 Sep, 00:50 WIB (02:50 JST)
The Japan Meteorological Agency reports a large eruption; Himawari-9 satellite imagery puts the plume at roughly 15 km (48,000–50,000 ft) above sea level.
Sun 6 Sep, 00:04 WIB
The continuous eruption ends, roughly 25 hours after it began. Badan Geologi confirms activity has "decreased again" but keeps the alert at Level III, saying monitoring continues given the potential for further eruptions.
Sun 6 Sep, 03:53 WIB
The first discrete eruption after the continuous episode: maximum amplitude 46 mm, duration 30 seconds. The ash column is not observed.
Sun 6 Sep, 07:10 WIB
A second discrete eruption: maximum amplitude 50 mm, duration 16 seconds. Again the ash column is not observed.
Sun 6 Sep, 20:23 WIB
A third discrete eruption: maximum amplitude 58 mm, duration roughly 44 seconds. Badan Geologi's own recap the next morning describes these three as strombolian eruptions producing black ash columns of unrecorded height.
Mon 7 Sep, 06:00 WIB recap
Badan Geologi's instrumental summary for 6–7 September logs 3 eruption earthquakes, 9 explosion earthquakes, 93 low-frequency earthquakes, 98 hybrid/multi-phase earthquakes, 4 continuous tremors and 1 shallow volcanic earthquake — a busy seismic day even without a further discrete eruption being separately announced. Visual observation is variable (clear to overcast, weak-to-moderate winds from the north/northwest), and the alert stays at Level III.
Tue 8 Sep, 05:08 WIB
The first eruption of the day: maximum amplitude 47 mm, duration 15 seconds. The column is not visually observed — fog is covering the volcano at the time, per the Anak Krakatau monitoring post in South Lampung.
Tue 8 Sep, 05:34 WIB
A second eruption follows about 26 minutes later: maximum amplitude 44 mm, duration 10 seconds.
Tue 8 Sep, 07:49 WIB
A third eruption of the morning: maximum amplitude 48 mm, duration 19 seconds — this time with an observed ash column reaching roughly 7,000 ft (2.1 km), moving south-southwest toward northwestern Banten and the northwestern Indian Ocean. BPBD Lampung issues an eruption-detection alert. This brings the confirmed discrete-eruption count since 6 September to six.
Tue 8 Sep, 11:34 WIB
A fourth eruption of the day: maximum amplitude 50 mm, duration 17 seconds, ash column not visually observed. This is the seventh discrete eruption confirmed since 6 September.
Tue 8 Sep, ~12:00 WIB
The latest forecast has the news turning more favourable: BMKG's ash-dispersal forecast now has the plume moving away from Indonesian territory rather than over it, a reversal from the westward-expansion forecasts earlier in the week. Badan Geologi's hazard assessment still flags an elevated probability of further eruptions in coming days, with the main threats being ejected incandescent rock and heavy ashfall near the crater, and renewed lava flow if a continuous eruption resumes.
Wed 9 Sep, 00:47 WIB
An eighth discrete eruption since 6 September: maximum amplitude 51 mm, duration 28 seconds — at the time, the strongest single reading since the 58 mm eruption on 6 September evening. The ash column height was not observed. PVMBG's instrumental log for the event also records one eruption earthquake, one low-frequency earthquake, one hybrid earthquake and continuous tremor. Alert level remains Level III (Siaga); the 3 km exclusion radius is unchanged.
Thu 10 Sep
Eruptions continue at a lower frequency — Badan Geologi's later reporting confirms this is the last day any were recorded before activity paused — but we did not find individual amplitude/duration figures for this specific day's event(s) from a source we could verify, so none are itemized here.
Fri 11 Sep – Sun 13 Sep
No further eruptions are recorded for three consecutive days — the longest quiet stretch since the crisis began on 4 September. Seismicity is trending down overall, but Suwarno, head of the Anak Krakatau monitoring post in South Lampung, says a status downgrade "is not that simple" and requires more sustained data: "even though the earthquake frequency is declining, the tremor is still fairly large, and that has to be taken into account." On Sunday, low-frequency earthquakes and continuous tremor of 1–10 mm amplitude were still being logged. Badan Geologi separately notes that deeper volcano-tectonic earthquakes — an indicator of magma supply from depth — have shown an increasing trend, which is why Level III (Siaga) stays in force despite the pause in surface eruptions.
Mon 14 Sep
Anak Krakatau logs four more earthquakes today; the summit itself is obscured by thick fog, so no visual confirmation of activity is possible. Alert level remains Level III (Siaga), unchanged since 2 July.
Tue 15 – Thu 17 Sep
PVMBG confirms no eruptions were recorded on 14 or 15 September. On 17 September PVMBG head Rita Susilawati says activity "has returned to a normal Strombolian eruption pattern of short duration," and describes the volcano's rapid regrowth as normal behaviour for a young cone: it now stands about 150 m high with relatively gentle slopes, so "if a collapse happens now, it will not cause a tsunami." Monitoring continues around the clock. No change to Level III (Siaga) or to the 3 km exclusion radius has been announced, and we found no report of an eruption on 16 or 17 September.
Fri 18 – Mon 21 Sep, morning
We found no report of a new eruption over these days. Badan Geologi's MAGMA observation report for 00:00–06:00 WIB on Monday 21 September still shows Anak Krakatau at Level III (Siaga): the volcano is covered by fog and no crater smoke is observed, under cloudy skies with weak winds toward the northwest.
Mon 21 Sep, 18:30 WIB
Badan Geologi head Lana Saria announces Anak Krakatau's alert level is downgraded from Level III (Siaga) to Level II (Waspada), effective immediately: "The activity level of Anak Krakatau volcano is downgraded from Level III (Siaga) to Level II (Waspada)." The exclusion radius is cut from 3 km to 2 km around the crater. The stated basis is declining seismicity — 20 September's data logged just one low-frequency earthquake and continuous tremor averaging 2 mm amplitude — continuing the trend since the last confirmed eruption on 9 September. Residents, visitors, tourists and climbers remain barred from the new 2 km zone, and Badan Geologi says it will keep evaluating and adjust the status again if activity changes significantly.
Tue 22 Sep
PVMBG head Rita Susilawati reports, via the Badan Geologi's official account, that Sentinel satellite imagery shows the volcano's land area has grown by 32.8 hectares — new material on its northwest, west and southwest sides from the pyroclastic deposits and lava flows of the 4–6 September continuous eruption — and that two small island-like mounds have appeared to its northwest and southeast. PVMBG's preliminary reading is that thin magma reached the surface through a fracture opening from the west; it will compare before-and-after imagery and verify in the field, so treat the mounds' origin as unconfirmed for now. The 2 km exclusion radius stays in force.
Thu 24 Sep
No new eruption has been reported since the downgrade. Separate reporting says the Merak–Bakauheni ferry crossing and Anyer-area tourism remain unaffected. Hazards Badan Geologi still flags within the 2 km zone: ejected rock, heavy ashfall and potential lava flow; the agency repeats that any viral tsunami warning not sourced to BMKG or Badan Geologi itself should be treated as unconfirmed.
From early Oct
Badan Geologi notes a low-scale rise in volcanic activity since early October, as part of the evaluation behind the 9 October decision.
Tue 6 – Fri 9 Oct
Badan Geologi counts 14 eruptions in these four days, against the quiet spell that had led to the 21 September downgrade.
Fri 9 Oct, 21:00 WIB
Badan Geologi raises Anak Krakatau from Level II (Waspada) back to Level III (Siaga), effective 21:00 WIB, on the basis of evaluation report 1729.Lap/GL.03/BGL/2026 dated 9 October, which covers 21 September to 9 October. The exclusion radius is widened from 2 km to 5 km around the crater, and activity is also banned within 1 km of the new island-like mounds to the northwest and southeast. Hazards flagged: ejected incandescent rock, heavy ashfall, lava flow, and secondary eruptions where hot material meets seawater or rain.
Fri 9 – Sat 10 Oct
The Anak Krakatau monitoring post in South Lampung (head Suwarno) reports 26 eruptions in 24 hours, with amplitudes of 28–66 mm and durations of 12–752 seconds (about 12.5 minutes). No ash column or eruption column is observed, but visual observation is hard because some surveillance cameras are not operating. Residents are urged not to believe reports that the eruptions will cause a tsunami.
Sat 10 Oct
BMKG, analysing Himawari-9 RGB imagery, reports ash dispersal from the surface up to about 6,000 ft (1.8 km) toward the west, over part of the western Sunda Strait off Pandeglang. Disaster expert Daryono of IABI says the raise is a step for vigilance and early mitigation, "not a reason to panic".

Key points

Volcano status: Level III (Siaga) since 21:00 WIB on 9 October 2026, raised from Level II (Waspada), which had applied since 21 September. The exclusion zone is 5 km around the crater, plus 1 km around the new island-like mounds to the northwest and southeast, and binds residents, tourists, fishermen and climbers.
This is a dedicated eruption-activity log, separate from our articles on airport closures/reopening, Jakarta-city ashfall, and the health-ministry response — check those for operational and health guidance rather than this page.
Hazards flagged for the exclusion zone: ejected incandescent rock, heavy ashfall, lava flow, and secondary eruptions where hot material meets seawater or rain.
How to read the raise: disaster expert Daryono of IABI says the status change is for vigilance, not panic. Visual observation is limited — some surveillance cameras were out of order. Treat any tsunami warning not sourced to BMKG or Badan Geologi as unconfirmed; residents are urged not to believe reports that the eruptions will cause a tsunami.
Running tally: eight discrete eruptions confirmed on 6–9 September, then 14 eruptions on 6–9 October, with 26 counted in one 24-hour window reported on 10 October. The ash dispersal BMKG reported reaches about 6,000 ft (1.8 km), well below the estimated 15 km plume of the 4–5 September continuous-eruption phase.
Knock-on effects: in the reports we found for 9–12 October there is no airport closure, NOTAM or ferry disruption; the airport closures of early September (see our separate airport articles) have not been repeated. The Merak–Bakauheni ferry crossing and Anyer-area tourism were reported unaffected in September.
Land growth: Sentinel satellite imagery reported by PVMBG on 22 September showed the volcano's land area up by 32.8 hectares since the 4–6 September eruption, with two small island-like mounds to the northwest and southeast. PVMBG's preliminary reading was a fracture opening from the west, with field verification pending; the 1 km zone around the new mounds is part of the current exclusion rules.
For the human cost connected to this eruption, see our separate article on the search for eight people, including five journalists, missing near the volcano since 7 September — one of whom, crew member Surakman, has since been identified and buried.

What this means for your Indonesian entity

This log is a standing reference for one question: is the volcano still active? Keep it bookmarked separately from operational updates. The answer since 9 October is yes: the alert is back at Level III (Siaga) and the exclusion zone is 5 km, up from 2 km. For most offices this changes nothing today — the zone is over water and around the volcano itself, and we found no airport closure, NOTAM or ferry disruption in the reports for 9–12 October. If your staff or operations are in Banten, Lampung, or coastal West Java, the practical trigger for action is the same as in September: watch for fresh ashfall or mask advisories from BPBD, and for airport notices if your travel runs through Soekarno-Hatta, Halim or Radin Inten II, rather than relying on the alert level alone. Keep any exclusion-zone planning to the 5 km figure. We will add new eruptions to this timeline as Badan Geologi confirms them, and will note here if the status changes again in either direction.

Sources

This page summarises publicly available information for orientation. It is not tax, legal, or accounting advice, and regulations change. Verify against the linked primary sources and contact us before acting on anything here.

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