Mount Semeru Erupts, Blowing Out Hot Clouds and Throwing Glowing Rocks

BANDUNG, KOMPAS - Mount Semeru in East Java is currently at an Alert status or Level IV. This status is the highest to indicate volcanic activity in Indonesia. The dangers of hot clouds and the eruption of incandescent rocks are the most important concerns for the residents in the surrounding areas.

Previously, the increase in activity of Semeru occurred very rapidly. On Tuesday (19/11/2025) at 16:00 WIB, after the eruption released a hot cloud at 14:13 WIB, the Geological Agency raised the status of the volcano from Level II or Alert to Level III or Standby.

Just one hour later, its status was raised again, from Alert to Level IV or Warnings at 5:00 PM WIB. One of the considerations was that the hot cloud activity was still ongoing with a maximum amplitude of 37 millimeters.

The Head of the Geological Agency, Muhammad Wafid, stated that the activity of Semeru indicates that eruption and lava flow activities are still occurring. However, visually, it has not been observed to the fullest due to weather conditions.

During this period, the number of recorded earthquakes indicates that seismic activity in Semeru remains high, particularly for eruption, collapse, and harmonic earthquakes. The recorded earthquakes suggest that there is still a flow from beneath the surface of Semeru, along with the release of material to the surface through eruptions and blasts.

"From visual observations, it was observed that the incandescent lava avalanches were becoming more intense towards Besuk Kobokan," he said.

Therefore, along with the increase in activity and status, the restricted zone for human activities around Semeru is expanding. Both the community, visitors, and tourists are urged not to engage in activities in the southeastern sector along Besuk Kobokan, up to 20 kilometers from the eruption center.

Wafid also stated that they were asked not to engage in activities within 500 meters from the riverbank along Besuk Kobokan. Hot clouds and lava are prone to flow through Besuk Kobokan.

In addition, the community in other sectors is also advised not to engage in activities within a radius of 8 km from the crater or summit of Semeru due to the risk of hazardous volcanic rock eruptions.

Meanwhile, Rudi, a member of the Lumajang Disaster Preparedness Cadets, told Kompas that 22 families in Candipuro District, Lumajang, are taking refuge at the sub-district office. He is currently on site assisting with the evacuation of residents.