Six Volcanoes, One Rare Overlap
Indonesia is no stranger to volcanic activity. It sits on the Pacific Ring of Fire, hosts 127 active volcanoes, and the Smithsonian Institution records 55 that have erupted since 1960, more than any other country. Yet even by those standards, what happened recently was unusual: six volcanoes erupted within a very short window, spreading ash across Java and Sumatra, grounding thousands of flights, and affecting more than 340,000 passengers.
The volcanoes involved were Anak Krakatau in the Sunda Strait, Semeru in East Java, Ile Lewotolok and Lewotobi Laki-laki in East Nusa Tenggara, Mount Ibu in North Maluku, and Mount Sinabung in North Sumatra. As first reported by ABC News, Indonesia's Meteorology, Climatology and Geophysics Agency (BMKG) was also detecting ash from mounts Lewotolo, Ibu, Dukono, and Semeru as the situation developed.
Why Scientists Call It a Coincidence
Indranova Suhendro, an assistant professor at Gadjah Mada University's Faculty of Geography, told ABC News that two or three simultaneous eruptions are fairly common in Indonesia, but six at once is rare, even across decades or centuries. Each volcano operates on its own magma system and eruption cycle. Some, like Semeru and Anak Krakatau, are relatively frequent; others stay quiet for years. This time, those independent cycles simply overlapped. Dr. Suhendro was clear that one volcano does not trigger another, since the systems are separate and the distances between them are large. "In terms of timing I think it really was a coincidence," he said.
Ash Reaches Jakarta, Flights Disrupted
The reach of the ash surprised even people who grew up near active volcanoes. Jakarta resident Cendy Rahmat, who spent his childhood near Mount Merapi in Yogyakarta, told ABC News he was caught off guard when the Jakarta government confirmed that ash from Anak Krakatau, roughly 150 kilometres away, had reached parts of the capital. Anak Krakatau remains at Level III ("Alert") with a 3-kilometre exclusion zone in place.
For context on how far ash can travel: the 2014 eruption of Mount Kelud spread ash some 500 kilometres across Java, forced tens of thousands to evacuate, and closed at least seven airports.
Living With Volcanoes
For communities near Merapi, this is simply life. Abid Rahmatullah, from Ngemplak district about 18 kilometres from Merapi's summit, described the volcano as "like a playground," noting the benefits of fertile land, clean water, and dramatic views. At night, lava avalanches resemble fireworks on the slopes. Residents stay informed through official updates shared via WhatsApp groups, a practical system that reflects how deeply volcano monitoring is embedded in daily routines.
Disaster Funding Under Scrutiny
The eruptions have renewed debate about Indonesia's disaster preparedness budget. The Indonesian National Disaster Management Agency (BNPB) received Rp1.43 trillion (approximately $113 million) in the 2025 state budget, but the 2026 allocation dropped to around Rp491 billion (approximately $39 million). The government has proposed raising it to roughly Rp1 trillion (approximately $79 million) in the draft 2027 budget. Civil groups have challenged the 2026 budget in Indonesia's Constitutional Court. Dr. Suhendro called reducing disaster preparedness funding "very unwise" given the country's exposure to natural hazards.
Why It Matters for Hosts
Independent accommodation and tour operators across Java, Sumatra, and eastern Indonesia should treat this event as a prompt to review their guest communication protocols. Ash events can arrive with little notice, disrupt airport access, and affect air quality far from the eruption source. Having a clear, pre-written update ready for guests, knowing the current alert levels for the nearest volcano, and maintaining flexible cancellation terms during elevated alert periods are all practical steps that protect both guests and the business. Monitoring BMKG and BNPB alerts directly, rather than waiting for news coverage, gives operators the earliest possible warning.
Details in this post were first reported by ABC News.
First reported by abc.net.au.