Mount Semeru Eruption Accompanied By Eruption, Launches Incandescent Lava

Mount Semeru erupted again with an eruption height of 1,000 meters above the peak and accompanied by incandescent lava slides on Monday (8/12/2025) night.ANTARA/HO-PVMBG

LUMAJANG - Mount Semeru erupted again with an eruption as high as 1,000 meters above the peak and incandescent lava slides on Monday night.

"There was an eruption of Mount Semeru on Monday, December 8, 2025, at 21.24 WIB," said Mount Semeru Observation Post Officer Mukdas Sofian in a written report quoted by ANTARA.

According to him, the height of the eruption column was observed to be approximately 1,000 meters above the peak or 4,676 meters above sea level.

"The ash column was observed to be white to gray with thick intensity to the southwest. The eruption was recorded on a seismograph with a maximum amplitude of 22 mm and a duration of 182 seconds," he said.

The highest mountain on the island of Java was also observed from the Observation Post launching incandescent lava from above the peak and visible beams of fire falling downwards.

The status of Mount Semeru is still at Level III or alert, so the Center for Volcanology and Geological Hazard Mitigation (PVMBG) provides a number of recommendations, namely not carrying out any activities in the southeast sector along Besuk Kobokan, as far as 13 km from the summit (the center of the eruption).

"Outside of that distance, people do not carry out activities at a distance of 500 meters from the riverbank (river border) along Besuk Kobokan because it has the potential to be affected by the expansion of hot clouds and lava flows up to a distance of 17 km from the summit," he said.

The community is also prohibited from doing activities within a 5 km radius of the crater/peak of Mount Semeru because it is prone to the danger of throwing stones (pijar).

The public is also asked to be aware of the potential for hot clouds of avalanches (APG), lava avalanches, and lahars along rivers/valleys that originate at the peak of the Semeru Volcano, especially along Besuk Kobokan, Besuk Bang, Besuk Kembar, and Besuk Sat as well as the potential for lahars in small rivers which are tributaries of Besuk Kobokan.