As the country enters September 2026, eruptions were recorded at several volcanoes, including Mount Ile Lewotolok in East Nusa Tenggara, Mount Semeru in East Java, Mount Sinabung in North Sumatra, and Mount Anak Krakatau in Lampung.
From September 1 to 5, 2026, alone, Mount Ile Lewotolok was reported to have erupted 1,873 times, with heights reaching 200-700 meters from the summit. The series of eruptions continued on Monday morning, with two eruptions recorded—one at 05:41 a.m. local time and another at 06:15 a.m. local time—spewing ash columns approximately 600 meters above the peak.
Related news: RI readies 10 airports to restore flights after Anak Krakatau eruption
Mount Semeru erupted on Sunday morning (Sept 6), sending an ash column 1,000 meters above its summit. The event triggered a warning prohibiting people from carrying out activities within five kilometers of Semeru’s crater because of the risk of incandescent rock ejected by the eruption.
Meanwhile, a major eruption at Mount Sinabung on Monday morning (August 31) sent a dense column of volcanic ash rising approximately 3.5 kilometers above its peak, followed by an increase in the volcano's alert level from Level II (Alert) to Level III (Standby).
Mount Anak Krakatau then captured the spotlight above all others.
Continuous eruptions have hit the island volcano since Friday night (Sept 4), marking its most intense activity this year. Although the phase ended early on Sunday morning, the event sparked major public concern as volcanic ash drifted across various regions—including Greater Jakarta, Banten, and Lampung—significantly disrupting aviation.
Related news: Govt stated Mt. Anak Krakatau's 25-hour eruption episode ends
Ash-induced disruptions
Beyond the immediate geological hazard, the heightened volcanic activity across several volcanoes caused significant operational and social disruptions, hitting aviation safety and local communities hardest.
Following the increase in Mount Sinabung's alert status to Level III, the National Disaster Mitigation Agency (BNPB) urged residents of Karo District in North Sumatra to immediately evacuate to safe areas.
Berton S.P. Panjaitan, the acting head of Disaster Data, Information, and Communication Center at the BNPB, noted the volcanic ashfall was significantly impacting residential areas and agricultural land in Ndokum Siroga and Kuta Tengah villages in Simpang Empat Sub-district, as well as Payung Village in Payung Sub-district.
The eruption also disrupted flights between Jakarta’s Soekarno-Hatta International Airport and North Sumatra's Kualanamu International Airport, prompting cancellations and delays.
As for Mount Anak Krakatau, the continuous eruption triggered widespread ashfall that raised safety concerns among the public, prompting schools to implement remote learning.
Related news: Lembata's Ile Lewotolok erupts 1,873 times over five days
According to the BNPB, three districts are the most severely affected by Mount Anak Krakatau's volcanic activity; they are South Lampung and Tanggamus in Lampung Province, and Pandeglang in Banten Province.
On the aviation front, volcanic ash forced the temporary suspension of operations across several key air transport hubs.
As of 1:00 p.m. Western Indonesia Time on Sunday (Sept 6), six airports remained temporarily closed, including Soekarno-Hatta International Airport and Budiarto Airport in Tangerang, Pondok Cabe Airport in South Tangerang, Halim Perdanakusuma International Airport in East Jakarta, Radin Inten II Airport in Lampung, and Husein Sastranegara International Airport in Bandung, West Java.
Assistant Deputy of Communication and Legal at Soekarno-Hatta International Airport, Yudistiawan, mentioned 1,039 flights at the airport were affected by volcanic ash of Mount Anak Krakatau's eruption on Sunday (Sept 6).
The figure is a cumulative total of cancellations, delays, flight diversions, and other disruptions. The affected flights comprised 746 domestic flights, 272 international flights, and 21 cargo flights, affecting a total of 166,351 passengers.
Related news: Three Indonesian volcanoes erupt in rapid succession Tuesday night
Response measures
In addition to issuing warnings to residents, the Indonesian government and local authorities have moved to respond to the impacts of volcanic ash on public health and the aviation sector.
Following the eruption of Mount Sinabung, joint rescue teams evacuated at least 615 villagers to shelters in order to protect them from potential eruption hazards. A total of 1,279 personnel have also been deployed to assist the affected residents.
The joint force comprises members of the Indonesian Military (TNI), the National Police (Polri), the Karo District Government, the local Disaster Mitigation Agency (BPBD), and the Search and Rescue Agency (Basarnas).
As for the widespread impact of Mount Anak Krakatau's eruption, President Prabowo Subianto has urged the public—particularly those in Jakarta, Banten, Lampung, and around the Sunda Strait—to remain calm and stay vigilant, while continuing to adhere to the danger zones and safety perimeters established by the authorities.
President Prabowo affirmed to continue closely monitoring the situation and take all necessary measures to ensure public safety and protect citizens.
Related news: Mt. Lewotobi Laki-laki erupts five times, spews ash up to 1,000 meters
As the ash triggering public health concerns, the Ministry of Health has activated its Health Emergency Operation Center (HEOC) and readied supplies—including nebulizers, oxygen concentrators, and eye drops—to address respiratory and other ash-related conditions.
Meanwhile, BNPB is preparing weather modification through cloud seeding to trigger rainfall and wash away the volcanic ash. Operations are set to begin as soon as weather conditions and flight safety allow.
Furthermore, to speed up the recovery of flight schedules disrupted by the Mount Anak Krakatau eruption, the Ministry of Transportation has prepared 10 airports to operate 24 hours a day, serving as alternatives for the affected airports.
Five of the 10 airports include Kertajati International Airport in Majalengka, Juanda International Airport in Surabaya, Jenderal Ahmad Yani International Airport in Semarang, Adi Soemarmo International Airport in Surakarta, and Yogyakarta International Airport.
Authorities continue to monitor activity across all active volcanoes as mitigation and recovery efforts proceed.
Related news: Mount Semeru erupts, ash column reaches 800 meters
Editor: Fransiska Ninditya
Copyright © ANTARA 2026
