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

Mount Semeru in East Java erupted again on Monday (April 20, 2026) at 8:59 PM WIB. In the past week, Mount Semeru has erupted 5 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).

No eruption visuals were observed. The eruption of Mount Semeru was still ongoing when this report was made.

(Read: 5.5 M Earthquake Shakes 262 Km East of Levuka,)

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

Then, 4 emission earthquakes with an amplitude of 2-3 millimeters and a duration 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). Outside this 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 the expansion of hot clouds and lava flows up to 17 kilometers from the peak.

During 2026, MAGMA Indonesia has recorded 1,578 volcanic eruptions across Indonesia. Mount Semeru in East Java had the most eruptions with 837 events.

(Read: Earthquakes to Drought: These are the Natural Disasters That Often Occur in Indonesia Until Mid-2023)