TEMPO.CO, Jakarta - The eruption cycle of Mount Anak Krakatau has changed from about two years before 2018 to four years, said the volcanologist from the Bandung Institute of Technology (ITB), Mirzam Abdurrachman.

Located in the Sunda Strait, the volcano last erupted on December 22, 2018, claiming 400 lives and injuring thousands of people. Its status was recently increased from Waspada or Caution (level 2) to Siaga or Alert (level 3), as of Sunday, April 24, 2022.

Mirzam assessed that the rising seismicity indicated the movement of magma. “The eruption of Mount Anak Krakatau is a routine phase to expel excess magma,” said Mirzam on Monday night, April 25, 2022.

He emphasized that when the magma's position is already near the surface–which is indicated by the release of high SO2 gas–yet it does not come out or erupt, its shallow position will be very vulnerable to external factors. Consequently, it could trigger a sudden eruption like what happened in Hawaii in 2018.

Based on the results of the ITB study, it was indicated that the magma chamber on Mount Anak Krakatau was filled by two different sources; the melting of plates due to subduction and the depths of the Earth's mantle layer.

“So that Anak Krakatau is now in the growth phase to establish a larger cone due to the accumulation of eruption products,” Mirzam explained.

Thus, when asked about the potential recurrence of the devastating eruption which led to a tsunami in 2018, Mirzam argued that it might happen but it is not something to be worried about at this time. “Because the current volume is still small and far from the size of the body of Mount Anak Krakatau in 2018,” he said.

Read: BNPB Monitors Impact of Mount Anak Krakatau's Eruption during Mudik Period

ANWAR SISWADI (CONTRIBUTOR)