Alert Status: Mount Semeru Eruption Twice, Seismic Activity Recorded 37 Times

Mount Semeru erupted with an eruption height of 700 meters above the peak on Wednesday (6/8/2025). (ANTARA)

LUMAJANG - Mount Semeru which has an altitude of 3,676 meters above sea level (masl) has erupted again with an eruption height of about 700 meters above the peak on Wednesday, August 6, 2025.

"There was an eruption of Mount Semeru at 10.08 WIB with an eruption column height of about 700 meters above the peak or 4.376 meters above the peak," said Mount Semeru Observation Post Officer Mukdas Sofian, quoted by ANTARA, Wednesday morning.

According to him, the ash column was observed to be white to gray with thick intensity to the north and northeastern. The eruption was recorded on a seismograph with a maximum amplitude of 22 mm and a duration of 167 seconds.

The mountain, which is on the border of Lumajang and Malang Regencies, was previously also an eruption at 05.24 WIB with an eruption column height of about 600 meters above the peak (4,276 mdpl).

The ash column was observed to be white to gray with moderate intensity to the north. When the report was made, the eruption was still ongoing.

The activity of Mount Semeru is still dominated by earthquake eruptions which recorded seismic activity on Tuesday (5/8) as many as 37 eruption/eruption earthquakes with an amplitude of 10-22 mm, and an earthquake of 65-188 seconds.

Mukdas explained that Mount Semeru is still on Alert or Level II status, so that the Center for Volcanology and Geological Hazard Mitigation (PVMBG) provides a number of recommendations, namely that people are prohibited from carrying out any activity in the southeast sector, along Besuk Kobokan as far as eight kilometers from the summit (the center of the eruption).

Outside of that distance, he said, people are not allowed to carry out activities at a distance of 500 meters from the riverbank 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 13 kilometers from the summit.

"The public is also advised not to move within a three-kilometer radius of the crater/peak of Mount Semeru, because it is prone to the dangers of incandescent stones," he said.

He appealed to the public to be aware of the potential for hot clouds, lava avalanches, and rain lava along rivers/valleys whose water flows originate at the top of Mount Semeru, especially along Besuk Kobokan, Besuk Bang, Besuk Kembar, and Besuk Sat, as well as the potential for lava in small rivers which are tributaries from Besuk Kobokan.