Mount Semeru Erupts Again, Height Reaches 1.2 Km

Mount Semeru/ Photo: ANTARA

JAKARTA - Mount Semeru, which is on the border of Lumajang and Malang Regencies, East Java, erupted again with an eruption height of 1.2 kilometers above the peak on Sunday morning.

"There was an eruption of Mount Semeru on December 21, 2025 at 05.46 WIB with an observed eruption column height of about 1,200 meters above the peak or 4,876 meters above sea level (msl)," said Mount Semeru Observation Post Officer Liswanto in a written report quoted by VOI, Sunday, December 21, 2025.

According to him, the column of volcanic ash that was observed was white to gray in color with medium intensity and inclined to the northeast.

"The eruption was recorded on the seismogram with a maximum amplitude of 22 mm and a duration of about 2 minutes 12 seconds," he said.

He said the eruption of the highest mountain on the island of Java was still ongoing when the report was being made by officers.

Based on data, the eruption of Mount Semeru has been recorded six times on Sunday since 00.26 WIB until 06.00 WIB with eruption heights ranging from 500 meters to 1,200 meters above the peak.

Currently, Mount Semeru is at Level III status or Alert, so the Center for Volcanology and Geological Hazard Mitigation provides a number of recommendations, namely that the public should not carry out any activities in the southeast sector along Besuk Kobokan, as far as 13 km from the peak (center of the eruption).

Outside this distance, the public does not carry out activities at a distance of 500 meters from the river bank (river border) along Besuk Kobokan because they have the potential to be hit by the expansion of the hot cloud and lava flow up to a distance of 17 km from the peak.

"The public is also prohibited from carrying out activities within a radius of 5 km from the crater/peak of the Semeru Volcano because they are prone to the danger of stone throwing (pijar)," he said.

He also asked the public to be aware of the potential for hot clouds, lava discharge, and lahar along the river/valley flows upstream at the peak of the Semeru Volcano, especially along Besuk Kobokan, Besuk Bang, Besuk Kembar, and Besuk Sat, as well as the potential for lahar in small rivers which are tributaries of Besuk Kobokan.