Indonesian authorities warn of potential further Anak Krakatau eruptions as volcanic ash hinders rain-making efforts to clear the air.
JAKARTA: Efforts to induce rain following eruptions at Indonesia’s Mount Anak Krakatau are being hampered by volcanic ash, as authorities warned that further eruptions could occur at any time amid high seismic activity.
In its latest monitoring update covering 6 am to noon local time, the Geological Agency recorded 17 low-frequency earthquakes, 23 hybrid earthquakes, nine harmonic tremors and continuous tremor, while the volcano remained at Level III, the second-highest level in Indonesia’s four-tier volcano alert system.
The agency said it continued to closely monitor the volcano through the Anak Krakatau Volcano Observation Posts in Pasauran, Banten, and Kalianda, Lampung.
“All monitoring data are analysed and evaluated by volcanologists at the Geological Agency,” it said in its latest social media post on Monday.
Anak Krakatau has recorded a series of eruptions since Friday, sending volcanic ash across parts of western Indonesia and disrupting air travel, while the Geological Agency reported on Sunday that a prolonged eruption episode lasting about 25 hours had subsided.
However, the impact of the volcanic ash continued to be felt on Monday, with National Disaster Management Agency (BNPB) chief Suharyanto saying it had spread across at least four provinces, namely Jakarta, West Java, Lampung and South Sumatra.
He said BNPB had been trying since Sunday to induce rain through weather modification operations (OMC), but the effort was hampered by the volcanic ash, which had also forced the temporary closure of eight airports and prevented the operation from proceeding.
He said BNPB was considering three airports as bases for conducting the OMC: Pondok Cabe Airport near Jakarta once conditions allowed, Kertajati International Airport in West Java or Ahmad Yani International Airport in Semarang, Central Java.
“We have moved the weather modification aircraft from Kalimantan and it is now in Semarang. We can at least conduct OMC from there because Ahmad Yani Airport in Semarang is not closed,” he said during an online meeting on the latest disaster response chaired by President Prabowo Subianto and streamed live on Monday.
Meteorology, Climatology and Geophysics Agency (BMKG) chief Teuku Faisal Fathani at the same meeting said potential cloud formation and light to moderate rain were expected over areas affected by the Anak Krakatau eruption from Sept 9, providing conditions that could be enhanced through the OMC.
He said the operation remained challenging as volcanic ash could damage aircraft engines, reduce visibility and interfere with aircraft navigation and sensors, while operating farther from the Sunda Strait would reduce its effectiveness.
“The farther from the Sunda Strait, the less effective the weather modification operation will be,” he said, adding that operations from Ahmad Yani Airport in Semarang, for example, would have a more limited reach in inducing rain around the Sunda Strait.
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