Expert: Anak Krakatau's Activity Is Not Linked to the Sunda Strait Megathrust Cycle
JAKARTA – The activity of Mount Anak Krakatau is not connected to the megathrust cycle in the Sunda Strait. Although it lies within a tectonic region, the volcanic activity of Anak Krakatau and the potential for a major earthquake caused by the megathrust constitute two separate systems.
This was stated by BRIN Research Professor Prof. Danny Hilman Natawidjaja in an interview with Republika regarding the activity of Mount Anak Krakatau and the megathrust potential of the Sunda Strait.
“They are not related. If the megathrust site stands on its own, then in this case, I think the interaction is not particularly significant. In systemic terms, it is possible that volcanic activity or the release of magma at Krakatau could theoretically release some of the tectonic strain, or conversely, it could disrupt our own systems,” he said on Monday (7/9/2026).
According to Danny, in theory, volcanic and tectonic activity can indeed interact with one another. However, he emphasised that there is as yet no basis for linking the activity of Anak Krakatau with the Sunda Strait megathrust cycle.
“But all of that is speculative; there is no established relationship between Krakatau’s activity and the megathrust cycle,” he said.
Danny explained that volcanic systems and tectonic earthquakes are not entirely separate. Interaction between the two can occur, especially when they are located close to one another.
“The point is that volcanic systems and earthquakes are separate, but they can interact, particularly if their locations are close together. In the case of Krakatau, it is indeed influenced by tectonics, because it is located within a tectonic zone. But it is not connected to the megathrust or anything else, so volcanic and tectonic activity can interact significantly,” he said.
In his view, under certain conditions, tectonic activity can even trigger volcanic activity. Conversely, he noted that volcanic activity triggering tectonic activity is rarer.
“Sometimes the interaction does trigger volcanic potential. But the reverse is quite rare – it is quite rare for an eruption or volcanic activity to trigger tectonic activity,” he said.
Regarding the tsunami potential…