Mount Semeru Erupts Again Tonight (Monday, April 20, 2026)

Mount Semeru in East Java erupted again on Monday (April 20, 2026) at 11:05 PM WIB. In the past week, Mount Semeru has erupted 6 times.

Quoting eruption information from the Center for Volcanology and Geological Hazard Mitigation (PVMBG) via the MAGMA Indonesia application, the observed ash column height reached None meters above the peak (None meters above sea level).

Eruption visuals were not observed. The eruption of Mount Semeru was still ongoing when this report was made.

(Read: Number of Victims Displaced Due to Natural Disasters in Indonesia 2015-2024)

According to the MAGMA Indonesia volcano activity report, the activity level of Mount Semeru is at Level III (Alert). Earthquake observations on April 20, 2026 from 12:00 PM to 6:00 PM WIB showed 19 eruption/explosion earthquakes with amplitudes of 10-22 millimeters and durations of 67-253 seconds.

Then, 4 emission earthquakes with amplitudes of 2-3 millimeters and durations of 42-62 seconds, as well as 1 harmonic earthquake with an amplitude of 2 millimeters and a duration of 643 seconds.

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

In 2026, MAGMA Indonesia has recorded 1,579 volcanic eruptions across Indonesia. Mount Semeru in East Java has the most eruptions with 838 events.

(Read: Natural Disasters Damaged 220 Thousand Buildings in Indonesia in 2025)