Anak Krakatau Erupts: Volcanic Ash Reaches Jakarta, Flights Impacted
Volcanic ash from Mount Anak Krakatau has triggered 18 flight safety warnings across Indonesia, affecting air corridors over Jakarta and West Java.
JAKARTA — Indonesia’s Meteorology, Climatology, and Geophysical Agency (BMKG) is maintaining round-the-clock monitoring of Mount Anak Krakatau as volcanic ash clouds drift across major population centers, including the capital, Jakarta. Satellite imagery from Sunday, Sept. 6, 2026, confirmed two distinct clusters of ash extending from Banten and West Java toward Bengkulu, prompting urgent navigation alerts for regional aviation.
The volcanic activity has forced authorities to issue 18 Significant Meteorological Information (SIGMET) advisories since the eruption began at 11:23 p.m. local time (WIB) on Sept. 4. According to Andri Ramdhani, the Acting Deputy for Meteorology at BMKG, ash plumes have reached altitudes of 20,000 feet moving eastward and up to 50,000 feet in a westward direction, creating hazardous conditions for commercial flight paths.
Aviation Hazards and Atmospheric Drift
The spread of volcanic material is not confined to the Sunda Strait. Meteorologists are tracking the plumes in real-time as wind currents at higher altitudes shift the ash clouds across dense residential and aviation corridors. The situation remains highly sensitive, with minor atmospheric fluctuations necessitating constant recalibration of flight safety protocols.
The Geological Agency under the Ministry of Energy and Mineral Resources reported on Monday, Sept. 7, 2026, that the volcano remains in a state of high unrest. Between 6:00 a.m. and 12:00 p.m. local time, sensors detected 17 low-frequency earthquakes and 23 hybrid quakes. These seismic signatures indicate that the volcanic system remains active and capable of further eruptive activity.
Systemic Monitoring and Seismic Activity
The Soekarno-Hatta Meteorological Station has been at the forefront of the response, issuing the initial aviation weather warning immediately following the first eruption. Beyond the immediate threat to air travel, officials are also monitoring the marine environment in the Sunda Strait, as underwater tremors or landslides triggered by the eruption could rapidly alter local sea conditions.
The volcanic crisis coincides with a broader period of seismic instability in the region. BMKG records show a magnitude 5.4 earthquake struck 77 kilometers southeast of Cilacap, Central Java, on Sept. 4 at 12:05 p.m. local time. While that event did not trigger a tsunami, it was felt at an Intensity III Modified Mercalli scale. Subsequent seismic activity included a 4.2 magnitude quake in Bandung on Sept. 6 and a 4.4 magnitude event in Ruteng, Manggarai, the following day.
Despite the high volume of geological activity, BMKG officials maintain that their primary focus remains on the real-time movement of volcanic ash and providing accurate, life-saving data to the aviation industry. "We have implemented 24-hour observation as our primary measure," stated Ramdhani, emphasizing that the agency will continue to update flight corridors as new atmospheric data arrives.
