Indonesia’s Mount Semeru eruption triggers evacuations as alert level raised to highest warning

Indonesia’s Mount Semeru, the highest peak on Java island, erupted on Wednesday afternoon, 19 November 2025, prompting immediate evacuations across East Java.

According to the Indonesian Center for Volcanology and Geological Hazard Mitigation (PVMBG), the eruption sent pyroclastic flows nearly 13 kilometres downslope.

Hot clouds rising up to 5.5 kilometres were directed toward the Besuk Kobokan area.

PVMBG reported that seismographs recorded a maximum amplitude of 40 mm with a 16-minute, 40-second duration for the event.

Three Villages Impacted

Indonesia’s National Disaster Management Agency (BNPB) confirmed that three villages were affected.

According to a statement by BNPB Chief Lt. Gen. Suharyanto, the impacted communities included Supit Urang and Oro-Oro Ombo in Pronojiwo District, and Penanggal in Candipuro District.

Authorities raised Semeru’s alert level from Level III (Siaga/Standby) to Level IV (Awas/Warning) at 17:00 local time on 19 November.

Local teams began evacuating residents to temporary shelters shortly after the alert was escalated.

Initial BNPB data indicated that about 300 people had taken refuge at two primary evacuation sites.

Around 200 evacuees were housed at Oro-Oro Ombo Village Hall, while another 100 stayed at Supiturang 2 Elementary School.

Additional residents were relocated to Penanggal Village Hall, though officials continued field verification.

Suharyanto stated that the BNPB Operations Control Center was closely monitoring developments and that teams were instructed to respond swiftly to any casualties, damage, or displacement.

Continued Volcanic Activity on 20 November

Volcanic activity persisted into the morning of Thursday, 20 November.

Yadi Yuliandi of the Semeru Observation Post told state news agency Antara that 32 avalanche earthquakes were recorded between midnight and 06:00.

He reported amplitudes of 3–16 mm with durations of 69–108 seconds for these avalanche events. Semeru also recorded 25 eruption earthquakes, with amplitudes of 10–22 mm and durations of 71–141 seconds.

Yuliandi noted that Semeru remained at Level IV due to sustained activity.

He added that the volcano was visible to partially obscured by fog, with no crater smoke observed amid cloudy weather and light winds.

PVMBG urged communities to avoid the southeastern sector along Besuk Kobokan up to 20 kilometres from the summit.

The agency also advised residents to stay at least 500 metres from riverbanks due to the risk of expanding pyroclastic flows and lahars.

People were further instructed to avoid activities within an eight-kilometre radius of the summit.

Authorities stressed continued vigilance regarding potential pyroclastic flows, lava avalanches, and lahars within river valleys descending from the peak.

Hazard Warnings and Restricted Zones

In response to the eruption, the Lumajang Regency Government declared a seven-day emergency period from 19 to 26 November 2025.

State media reported the issuance of Circular Number 6/2025 to local leaders and communities.

Lumajang Regent Indah Amperawati announced the status through Regent Decree Number 100.3.3.2/595/KEP/427.12/2025.

She said the decree was intended to ensure a quick and coordinated response to the eruption. The circular called for heightened vigilance and instructed residents in high-risk zones to temporarily relocate.

Officials emphasised that updates would be provided as monitoring continued.