Mount Semeru Erupts Again Tonight (Friday, April 17, 2026)

Mount Semeru in East Java erupted again on Friday (April 17, 2026) at 23:42 WIB. In the past week, Mount Semeru has erupted 43 times.

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

The observed ash column is white to gray in color with thick intensity towards the southwest. The eruption was recorded on the seismograph with a maximum amplitude of 12 millimeters and a duration of 114 seconds.

(Read: Update on Number of Facilities Damaged by Floods and Landslides in Sumatra (December 11, 2025))

According to the MAGMA Indonesia volcano activity report, Mount Semeru's activity level is at Level III (Alert). Earthquake observations on April 17, 2026 from 12:00-18:00 WIB showed 18 eruption/explosion earthquakes with amplitudes of 10-22 millimeters and durations of 59-181 seconds.

Additionally, there were 5 emission earthquakes with amplitudes of 4-5 millimeters and durations of 46-67 seconds, as well as 1 distant tectonic earthquake with an amplitude of 5 millimeters, s-p time of 49 seconds, and duration of 102 seconds.

PVMBG advises against any activities in the southeast sector along the Besuk Kobokan, within 13 kilometers of the peak (eruption center). Beyond that distance, residents should avoid activities within 500 meters of the riverbank along the Besuk Kobokan due to the potential for hot cloud expansion and lahar flows up to 17 kilometers from the peak.

In 2026, MAGMA Indonesia has recorded 1,534 volcanic eruptions across Indonesia. Mount Semeru in East Java has the most eruptions with 818 events.

(Read: Two Months of Floods in Sumatra: 1,204 Dead and 140 Missing (Tuesday, January 27, 2026))