Expert: Magma Activity at Mount Anak Krakatau Remains High Despite Decreasing Seismic Activity
A disaster expert from the Sumatra Institute of Technology (Itera), Ikah Ning Prasetiowati Permanasari, has revealed that magma activity at Mount Anak Krakatau is still ongoing. This condition remains active even though the volcano’s seismic activity has shown a declining trend.
Ikah explained that assessments of Mount Anak Krakatau’s condition must be based on comprehensive data from the Centre for Volcanology and Geological Hazard Mitigation (PVMBG). She highlighted discrepancies between seismic indicators and deformation data.
“In truth, when discussing this, we must refer to the data. PVMBG data indicates that seismic activity has actually decreased, but tiltmeter station data still shows high levels related to magma,” said Ikah Ning Prasetiowati Permanasari in Bandar Lampung on Friday (11/9/2026).
According to Ikah, the presence of magma activity beneath the surface significantly affects the physical condition and stability of Mount Anak Krakatau. Although seismicity has decreased, the magma movement detected via tiltmeters indicates pressure that requires vigilance.
“Therefore, even though seismic activity has decreased, there is still activity down there. Thus, we must continue to wait, and hopefully, there will be no further surges in activity,” she said.
She added that due to this magma activity, the possibility of an eruption similar to the one on Friday (4/9) remains. However, she noted that the interval between eruptions has shown a significant reduction in intensity.
“Looking at the interval, it has increased significantly. However, for Mount Anak Krakatau, this type of eruptive activity is good for releasing energy so that it does not accumulate inside. The hope is that this energy can be released gradually,” she explained.
Regarding environmental impacts, Ikah stated that air quality in the affected areas has shown significant improvement based on recent measurements. Hazardous gas parameters, such as sulphur dioxide (SO2), were reported to have fallen below the standard quality threshold.
“SO2 levels and other parameters have dropped below the standard limits; only dust remains. Therefore, the use of masks must continue, as we do not know if this dust is mixed with volcanic ash,” she concluded.
Basarnas has expanded the search for five missing journalists at Mount Anak Krakatau across four sectors, deploying 13 ships on the fourth day of the SAR operation.
Polda Metro Jaya held a joint prayer for the eight missing victims, including five journalists, who were covering the eruption of Mount Anak ‘Krakatau’. Basarnas has deployed 13 ships.
Sultan urged the joint SAR team to continue maximising the search process for the five journalists and three crew members who remain missing.
The Indonesian Navy (TNI AL) discovered life jackets and a life buoy during the search for the five journalists in the Sunda Strait. Basarnas is currently identifying these findings.
The Head of Basarnas, Mohammad Syafii, requested that residents assisting in the search for the five journalists and three crew members at Mount Anak Krakatau strictly follow safety procedures.
Seventeen flights at I Gusti Ngurah Rai Airport in Bali were cancelled due to the volcanic activity of Mount Anak Krakatau.
Residents of eight villages at the foot of Mount Lewotobi Laki-Laki, East Flores Regency, East Nusa Tenggara (NTT), have been advised to be alert to the potential for mudflows.
A joint team has tightened patrols in the waters around Mount Anak Krakatau to prevent fishermen and tourists from entering the restricted zone for safety reasons.
PVMBG recorded 20 eruptions of Mount Anak Krakatau on 17 August 2026. The status remains at Level III (Alert) with a safe radius of 2 kilometres from the crater.
The Sulawesi-Maluku Volcano Monitoring Centre has set the status to Alert (Level II) for four volcanoes in North Sulawesi, including Mount Karangetang and Mount Awu.