Mount Semeru Erupts Again This Afternoon, Eruption Height Reaches 600 Meters Above Peak

Mount Semeru in East Java erupted again on Monday (April 20, 2026) at 16:25 WIB. In the past week, Mount Semeru has erupted twice.

Quoting eruption information from the Center for Volcanology and Geological Hazard Mitigation (PVMBG) via the MAGMA Indonesia application, the observed ash column height reached 600 meters above the peak (4,276 meters above sea level).

The ash column was observed to be gray in color with thick intensity towards the north. The eruption was recorded on the seismograph with a maximum amplitude of 22 millimeters and a duration of 122 seconds.

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According to the MAGMA Indonesia volcano activity report, Mount Semeru's activity level is at Level III (Alert). Earthquake observations on April 20, 2026 from 06:00-12:00 WIB showed 14 eruption/explosion earthquakes with amplitudes of 15-22 millimeters and durations of 77-130 seconds.

Then, 6 emission earthquakes with amplitudes of 3-6 millimeters and durations of 34-67 seconds, as well as 2 distant tectonic earthquakes with amplitudes of 4-5 millimeters, s-p times of 31-67 seconds, and durations of 81-115 seconds.

PVMBG advises against any activities in the southeast sector along the Besuk Kobokan, within 13 kilometers of the peak (eruption center). Outside this distance, residents are advised not to carry out activities within 500 meters of the riverbank along the Besuk Kobokan due to the potential for being affected by the expansion of hot clouds and lava flows up to 17 kilometers from the peak.

Throughout 2026, MAGMA Indonesia has recorded 1,572 volcanic eruptions across Indonesia. Mount Semeru in East Java has the most eruptions with 834 events.

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