The replay starts at 13:30 WIB on 5 September, the earliest recovered advisory. Press play or drag the clock to compare two views of the same Himawari-9 scan.
Replaying four days of Anak Krakatau satellite images, ash advisories and airport reports on a shared timeline.
The replay starts at 13:30 WIB on 5 September, the earliest recovered advisory. Press play or drag the clock to compare two views of the same Himawari-9 scan.
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Each panel shows the nearest scan to the selected time and clears if none is available within seven minutes. Ten of 589 time slots are missing; nothing is interpolated.
The infrared view shows brightness temperature. Cold areas can be high cloud tops—even above a hot vent—and weather clouds can look similar. JMA explains infrared imagery here.
Ash RGB combines four infrared bands to help distinguish cloud types; it does not measure ash concentration.
Line styles distinguish observed, estimated and forecast positions. Initial positions remain for an hour; forecasts appear only at their target time. Outlines are snapshots, not accumulated ashfall, and their absence does not mean the air was clear.
The airport track distinguishes scheduled closures and expiry from confirmed reopenings; gaps remain unknown.
Locations use official transport-ministry coordinates. BMKG’s “Atungbusu” refers to Atung Bungsu Airport in Pagar Alam. Its two reports name different sets of eight airports.
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Above are Darwin VAAC sequences for Merapi, Semeru, Lewotolok, Ibu and Dukono at the same distance scale. Several Merapi advisories from March 2023 report ash as not identifiable, so those cards have no outline.
The directory below lists the 127 volcanoes that Indonesia’s volcanology agency classifies as Type A, B or C from their recorded eruption history.
The archive begins more than 14 hours after the continuous eruption. The original airport NOTAMs are unavailable. Event markers use occurrence time, which may precede publication. This retrospective should not be used for current warnings.
The processing pipeline is in volcano-vis.
| Material | Source | Treatment |
|---|---|---|
| Infrared frames | Himawari-9 AHI band 13, JMA, via NASA GIBS | 579 ten-minute browse images, re-encoded as WebP |
| Ash RGB frames | Himawari-9 HSD bands 11, 13, 14, 15, JMA, via NOAA Open Data | Calibrated with Satpy, resampled and composited locally |
| Ash advisories | Darwin VAAC / Bureau of Meteorology, archived via BOM and GDACS | Coordinates, times and flight levels normalised; corrections retained |
| Chronology and airport reports | ESDM / PVMBG and BMKG press reports | Report-level statements with their stated times |
| Airport locations | DGCA, Kementerian Perhubungan | Official aerodrome reference points |
| Classification table | PVMBG / MAGMA Indonesia | All 127 rows as updated 20 September 2021 |
| Coastlines | Natural Earth v5.1.2 | Public domain |
Infrared browse images came from NASA GIBS; Himawari data originate with the Japan Meteorological Agency. These locally derived visualisations do not imply provider endorsement. Data snapshot: 12 September 2026.