Impact of Semeru Eruption, Lumajang Declares Emergency Response

MALANG, KOMPAS – Following the eruption on Wednesday (19/11/2025) afternoon, Mount Semeru no longer released hot ash clouds on Thursday morning. However, the Gladak Perak bridge connecting Malang and Lumajang is still not permitted for passage. Lumajang Regency has declared a state of emergency.

Following the eruption of Semeru on Wednesday afternoon, the condition of the southern route between Malang and Lumajang has not yet returned to normal. The Gladak Perak bridge is still generally closed for repairs.

"For Pronojiwo Village, the condition is safe and under control. However, the Gladak Perak bridge is officially still closed today (Thursday), as it still requires clearing of the route," said the Head of Pronojiwo Village, Murdiono, on Thursday (20/11/2025).

However, Murdiono acknowledged that many residents have dared to cross it. In fact, the condition of the bridge is slippery due to landslides and the debris from the eruption of Mount Semeru mixed with rainwater. The route still requires cleaning.

Meanwhile, some refugees returned to their homes to save their valuable belongings. Muhammad Kholil (50), for instance, was finally able to return to his home in Sumbersari Hamlet, Supiturang Village, Pronojiwo District, Lumajang Regency, after spending a night in evacuation due to the eruption of Mount Semeru.

Most of his house is destroyed. He returned to evacuate his pet birds. "The eruption itself started on Wednesday at 09:00 WIB. My family and I had already anticipated it. Especially when the eruption danger siren sounded at 15:30, the family immediately evacuated. I evacuated myself just before Maghrib," said Muhammad Kholil.

In Sumbersari Hamlet, many residents returned home to evacuate salvageable belongings. Since 05:00 WIB, residents who had previously evacuated returned home on foot due to the road leading to their houses being blocked by volcanic material.

During the monitoring on Thursday morning, from observations between 00:00-06:00 WIB, Mount Semeru erupted 25 times, recorded 32 avalanche earthquakes, experienced 1 puff, and 1 distant tectonic earthquake.

"The status of Semeru remains Alert. The public is urged to adhere to the recommendations of PVMBG (Center for Volcanology and Geological Hazard Mitigation), which advise against any activities in the southeastern sector along Besuk Kobokan, within a radius of 20 kilometers from the summit (the center of the eruption)," said the Head of PVMBG, Hadi Wijaya.

Outside of that distance, Hadi stated, the community does not engage in activities within 500 meters from the riverbank or river margins along the Besuk Kobokan. This is because the area is at risk of being affected by the expansion of hot clouds and lahar flows.

The public, according to Hadi, is also advised not to engage in activities within an 8-kilometer radius of the crater/summit of Mount Semeru. This is because the area is prone to the danger of rock eruptions (pyroclastic flows).

"We must remain vigilant of the potential for hot clouds, lava flows, and lahars along the river valleys that originate from the summit of Mount Semeru, particularly along Besuk Kobokan, Besuk Bang, Besuk Kembar, and Besuk Sat, as well as the potential for lahars in the small rivers that are tributaries of Besuk Kobokan," he said.

Mount Semeru in Lumajang Regency, East Java erupted on Wednesday (19/11/2025) at 16:00 WIB. The height of the observed eruption column was approximately 2,000 meters (m) above the peak (± 5,676 m above sea level). The observed ash column was gray in color with thick intensity towards the north and northwest. The status of Mount Semeru has been raised from Level II (Alert) to Level IV (Caution).

Volcanic ash from the Semeru eruption even reached the Gladak Perak bridge, the main bridge connecting Malang and Lumajang. The location of the bridge is 13 kilometers (km) from the summit of Mount Semeru.

Data from the National Disaster Management Agency (BNPB) indicates that there are three villages in two sub-districts affected by the eruption, namely Supit Urang Village and Oro-Oro Ombo Village in Pronojiwo Sub-district, and Penanggal Village in Candipuro Sub-district.

Preliminary data indicates that 300 residents have been displaced. The evacuation posts are spread across several locations, including the Oro-oro Ombo Village Hall with approximately 200 individuals and SD 2 Supiturang with 100 individuals. Additionally, there are a number of residents who have been evacuated to the Penanggal Village Hall.

"The Lumajang Regency Government has declared a state of emergency for the next week, effective from November 19, 2025, to November 26, 2025. This means that all matters related to the needs for addressing the impacts of Semeru will begin to be implemented, including regarding public kitchens, evacuation posts, and others," said Lumajang Regent Indah Amperawati when contacted on Thursday.

According to Indah, starting Wednesday night, Mount Semeru has stopped emitting hot ash clouds. "The hot ash clouds have ceased since last night, but the community must remain vigilant. We will focus on handling the refugees and the needs of the residents, as well as begin assessing the damage to infrastructure. Last night’s conditions were dark, making it impossible to conduct assessments. Please pray for us, may the people of Lumajang be able to get through this disaster well," she said.

Mount Semeru is the highest mountain on the island of Java, with an elevation of 3,676 meters above sea level. This mountain is one of the most active volcanoes in Indonesia. Not only is it capable of ejecting volcanic material from the summit, but Semeru can also release volcanic material from its flanks, as occurred in 1941. The potential for flank eruptions still exists to this day.

The area around Mount Semeru is divided into three disaster-prone zones (KRB). KRB III is an area with a high potential for being affected by hot clouds, lava, volcanic rock ejections, and toxic gases. Its area is located around the summit.

Next is KRB II, which is the area that has the potential to be affected by lava flows, ash rain, hot mud, and volcanic rock eruptions. Hot mud is likely to occur in Kali Manjing, Kali Gligik, Sumbersari, Besuk Sat, and Besuk Kobokan.

KRB I refers to areas that are at risk of being affected by lahar flows and are subject to falling materials such as ash rain. This area is divided into two, namely the lahar-prone area and the ash rain-prone area. The lahar-prone area is located along the valleys and riverbanks that originate from the peak region, including Kali Manjing, Kali Gligik, Besuk Sat, Besuk Kembar, Besuk Kobokan, Kali Pancing, and others.