Mount Semeru Erupts Again This Afternoon, Ash Plume 700 Meters Above Peak

Mount Semeru in East Java erupted again on Tuesday (9/23/2025) at 1:41 PM WIB. In the last week, Mount Semeru has erupted 11 times.

Based on eruption information from the Center for Volcanology and Geological Hazard Mitigation (PVMBG) via the MAGMA Indonesia application, the observed ash column reached 700 meters above the peak (4,376 meters above sea level).

The ash column was observed to be white to grey with thick intensity towards the southwest and west. The eruption was recorded on a seismograph with a maximum amplitude of 22 millimeters and a duration of 121 seconds.

(Read: 4.4 M Earthquake Jolts Babar, Indonesia)

According to MAGMA Indonesia''s volcanic activity report, Mount Semeru''s activity level is at Level II (Alert). Seismic observations on September 23, 2025, from 00:00-23:59 WIB, showed 65 eruption tremors with amplitudes of 11-22 millimeters and durations of 61-226 seconds.

Furthermore, there were 4 avalanche tremors with amplitudes of 2-3 mm and durations of 53-78 seconds, and 15 exhalation tremors with amplitudes of 3-8 millimeters and durations of 39-80 seconds.

PVMBG urges people not to carry out any activities in the southeast sector along Besuk Kobokan, as far as 8 kilometers from the peak (eruption center). Beyond that distance, people should not engage in activities within 500 meters from the riverbanks (river border) along Besuk Kobokan, as there is a potential for expansion of hot clouds and lava flows up to 13 kilometers from the peak.

Throughout 2025, MAGMA Indonesia has recorded 6,290 volcanic eruptions across Indonesia. Mount Semeru in East Java had the most eruptions, with 2,477 occurrences.

(Read: Indonesia Becomes Country Most Frequently Hit by Earthquakes as of 2025)