5 Volcanoes Erupt Simultaneously Across Indonesia, Here Is Mbah Rono's Explanation

Jakarta, CNBC Indonesia – Indonesia is currently beset by a wave of volcanic eruptions, involving among others Mount Anak Krakatau, Mount Sinabung, Mount Merapi, Mount Ibu and Mount Ili Lewotolok in East Nusa Tenggara (NTT).

Volcanologist Surono, affectionately known as Mbah Rono, has offered his analysis of the natural phenomenon involving these numerous volcanoes. He stressed that the current series of eruptions does not form a single connected system, but rather represents independent activity from each individual volcano.

“It is actually quite an ordinary occurrence because we simply have so many volcanoes, and they happen to erupt around the same time. But fundamentally, they each have different magma sources and different pressure sources,” he told CNBC Indonesia on Monday (7/9/2026).

Mbah Rono explained that Mount Anak Krakatau is currently in a natural growth phase to rebuild its body following the major collapse event in 2018. The continuous accumulation of magma pressure forces the volcano to erupt in order to expel new material that will pile up around its summit.

“Anak Krakatau naturally has to do this because it is naturally rebuilding its body. The magma supply is continuous, so pressure accumulates and has to be released. It must be released, ejecting new material that falls around its body, so Anak Krakatau grows bigger and taller,” he explained.

As for the eruption’s impact, which briefly disrupted operations at Soekarno-Hatta and Raden Inten airports, this was triggered by fine ash carried on the wind. Mbah Rono judged that the eruption risk appears high because national strategic vital objects lie within the reach of the volcanic dust dispersal.

“If there were no vital strategic objects near this eruption, it would not cause such a stir. The direct impact on humans is limited – the risk only appears high because there are vital strategic objects not far from Anak Krakatau’s reach,” he added.

The panic seen among communities, he argued, has arisen from a lack of consistent public education about the steps to take when a volcano’s alert status is raised. Mbah Rono urged that coordination between regional governments and BNPB, the national disaster management agency, be continuously strengthened so that information on emergency measures can be properly conveyed to affected residents.

“The panic exists because these events don’t happen every day. People haven’t heard information about what to do if difficulties like this arise,” he concluded.