Mount Marapi erupts again as authorities renew lahar warnings

INDONESIA — Mount Marapi in West Sumatra erupted again on Sunday afternoon, 14 December 2025, sending a column of volcanic ash up to 1,200 metres above its summit, authorities said. Despite the renewed activity, the volcano’s alert status has not been raised.

The Mount Marapi Volcano Observatory (PGA) reported that the eruption occurred at 16:37 Western Indonesia Time (WIB). The ash plume was grey, of moderate density, and drifted northward from the crater.

Teguh Firmansyah, a monitoring officer at Mount Marapi, said the eruption was clearly recorded by seismic instruments. “The seismogram showed a maximum amplitude of 9.8 millimetres, with a duration of one minute and one second,” he said.

He added that the volcano remains at Level II, or Alert, indicating heightened activity but no immediate escalation in status.

Straddling the Agam and Tanah Datar regencies, Mount Marapi is one of the most active volcanoes in West Sumatra. Monitoring has been intensified in recent years following a series of significant eruptions.

Authorities again urged the public to strictly comply with safety restrictions. The Centre for Volcanology and Geological Hazard Mitigation (PVMBG) reiterated that all activities are prohibited within a three-kilometre radius of the Verbeek Crater, the volcano’s main centre of activity.

The restriction applies to residents, tourists, and visitors, with officials warning that even brief entry into the exclusion zone could be dangerous due to the volcano’s unpredictable behaviour.

PVMBG also warned of the heightened risk of secondary disasters as West Sumatra enters the rainy season. Volcanic material deposited on Marapi’s slopes could be easily mobilised by heavy rainfall, increasing the threat of lahars, or volcanic mudflows.

“The accumulation of eruptive material can be carried by water flows and potentially cause lava floods at any time,” PVMBG said in an advisory.

The warning follows deadly lahar floods in May 2024, when mudflows from Mount Marapi claimed dozens of lives, highlighting the severe danger posed by secondary volcanic hazards.

Residents living along rivers and valleys originating from the volcano were urged to remain on high alert, particularly in areas such as the Anai Valley. Authorities advised communities to closely monitor river levels and to evacuate immediately if there are signs of sudden increases in water flow or volcanic debris.

Health risks linked to ashfall were also highlighted. Teguh advised residents to take protective measures if ash begins to fall in surrounding areas.

“If ash rain occurs, the public is strongly advised to use masks to cover the nose and mouth to prevent respiratory problems,” he said, warning of the risk of acute respiratory infections.

Ash particles can irritate the eyes, skin, and respiratory system, particularly among children, the elderly, and those with existing health conditions. Residents were encouraged to limit outdoor activities during periods of ashfall.

Marapi’s latest eruption came amid heightened volcanic activity across Indonesia on Sunday. The country lies along the Pacific “Ring of Fire” and is home to dozens of active volcanoes.

In North Maluku, Mount Ibu in West Halmahera erupted several times throughout the day and night, with one eruption producing an ash column rising about 500 metres above the summit, monitoring officers reported.

Mount Semeru, on the border of Lumajang and Malang regencies in East Java, also erupted, though its ash column was not visually observed.

Despite the simultaneous activity at several volcanoes, authorities said each event is being monitored individually. No evacuations have been ordered in connection with Mount Marapi’s latest eruption, apart from the existing exclusion zone.

Volcanology officers will continue round-the-clock monitoring of Mount Marapi, officials said, adding that further advisories will be issued if there are any changes in the volcano’s activity or alert level.