Mount Semeru Erupts Again This Morning (Tuesday, April 21, 2026)

Mount Semeru in East Java erupted again on Tuesday (April 21, 2026) at 07:05 WIB. In the past week, Mount Semeru has erupted 9 times.

Quoting eruption information from the Center for Volcanology and Geological Hazard Mitigation (PVMBG) via the MAGMA Indonesia application, the observed ash column height is approximately 1,000 meters above the peak (4,676 meters above sea level).

The ash column was observed to be gray in color with thick intensity towards the west. The eruption was recorded on the seismograph with a maximum amplitude of 22 millimeters and a duration of 182 seconds.

(Read: Number of Natural Disaster Events in Provinces on Java Island 2020-2024)

According to the MAGMA Indonesia volcano activity report, the activity level of Mount Semeru is at Level III (Alert). Earthquake observations on April 21, 2026 from 00:00 to 06:00 WIB showed 18 eruption/explosion earthquakes with amplitudes of 15-22 millimeters and durations of 78-155 seconds.

Then, 1 avalanche earthquake with an amplitude of 1 mm and duration of 45 seconds, as well as 2 emission earthquakes with amplitudes of 2-4 millimeters and durations of 95-98 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 1,584 volcanic eruptions across Indonesia. Mount Semeru in East Java has the most eruptions with 841 events.

(Read: After Spiking, Number of Natural Disaster Events in Indonesia Decreased in 2024)