Mount Semeru Erupts Four Times in One Morning, Ash Column Reaches 1,300 Metres
Mount Semeru (3,676 metres above sea level), located on the border of Lumajang and Malang regencies in East Java, experienced four eruptions within a three-hour period on Tuesday (14/7) morning. The volcanic ash column was recorded reaching up to 1,300 metres above the summit.
Head of the Mount Semeru Observation Post, Liswanto, stated that the first eruption occurred at 05:39 WIB, with the observed eruption column height reaching 1,300 metres above the peak, or approximately 4,976 metres above sea level. “The ash column was observed to be white to grey with moderate intensity moving northwards,” Liswanto said on Tuesday.
The second eruption took place at 06:29 WIB with an ash column height of 800 metres. The third followed at 06:51 WIB with an ash column reaching 1,200 metres. The fourth eruption occurred at 07:55 WIB with an ash column of 1,000 metres. This activity was recorded on a seismograph with a maximum amplitude of 22 millimetres and a duration of 100 seconds.
Liswanto urged the public and tourists not to conduct any activities in the southeastern sector along Besuk Kobokan, within a 13-kilometre radius from the summit or eruption centre. Beyond that distance, people are asked not to carry out activities within 500 metres of the riverbank along Besuk Kobokan due to the potential for being affected by expanding pyroclastic clouds and lava flows up to 17 kilometres from the summit.
“Do not conduct activities within a 5-kilometre radius of the crater or summit of Mount Semeru because it is prone to the danger of incandescent rock projectiles,” Liswanto said. He also urged the public to be aware of the potential for pyroclastic clouds, lava avalanches, and lahars along river flows or valleys originating at the summit of Mount Semeru, especially along Besuk Kobokan, Besuk Bang, Besuk Kembar, and Besuk Sat, as well as the potential for lahars in small rivers that are tributaries of Besuk Kobokan.
Throughout 2026, Mount Semeru has been recorded as having erupted 1,486 times. As of Tuesday (14/7) at 09:20 WIB, the volcano remains at Alert Level III. Based on data from the Centre for Volcanology and Geological Hazard Mitigation, during the period from 00:00 to 06:00 WIB on Tuesday, Mount Semeru experienced 16 eruption earthquakes with amplitudes of 13-22 mm and earthquake durations of 64-143 seconds. Additionally, three avalanche earthquakes were recorded with amplitudes of 1-4 mm and durations of 54-66 seconds, as well as two blast earthquakes with amplitudes of 3-7 mm and durations of 32-40 seconds.