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Tsunami sirens are built to detect earthquakes, but Anak Krakatau can kill without one, and our warning systems are still waiting for a shake that’s never coming.
Mount Anak Krakatau volcano spews hot lava as seen from Pasauran village in Serang, Banten, on Sept. 5, 2026. (Reuters/Rikardo)
The question left in the wake of the recent eruptions of Anak Krakatau is not whether the volcano will threaten the Sunda Strait again. It is whether we will still be waiting on a seismograph to tell us so when it does.In the early hours of Sept. 5, the Meteorology, Climatology and Geophysics Agency (BMKG) recorded the volcano’s most violent blast of 2026. A 15-kilometer ash column punched into the sky, paired with a sustained lava fountain that set the narrow strait between Java and Sumatra glowing for over an hour and a half.
The fallout was immediate: Transportation Minister Dudy Purwagandhi said over 2,900 domestic and international flights were grounded in a number of affected airports, including Soekarno-Hatta International Airport, until operations resumed on Tuesday. Thousands of kilometers away, the Japan Meteorological Agency issued a precautionary tsunami watch after picking up the acoustic-seismic signature of the blast.
