Mount Semeru Erupts Again Tonight, Ash Plume Around 800 Meters High

Mount Semeru in East Java erupted again on Sunday (January 4, 2026) at 10:19 PM WIB. In the last week, Mount Semeru has erupted 37 times.

Based on eruption information from the Center for Volcanology and Geological Hazard Mitigation (PVMBG) via the MAGMA Indonesia application, the ash plume was observed to be around 800 meters above the peak (4,476 meters above sea level).

The ash column was observed to be white to gray with thick intensity heading northeast. The eruption was recorded on a seismograph with a maximum amplitude of 22 millimeters and a duration of 105 seconds.

(Read: Floods, Natural Disasters That Frequently Hit Indonesia as of September 2025)

According to MAGMA Indonesia's volcano activity report, Mount Semeru's activity level is at Level III (Siaga/Alert). Seismicity observations on January 4, 2026, from 12:00 PM - 6:00 PM WIB showed 40 eruption quakes with amplitudes of 10-23 millimeters and quake durations of 69-178 seconds.

Then, 1 rockfall quake with an amplitude of 3 mm and a duration of 47 seconds, and 1 exhalation quake with an amplitude of 8 millimeters and a duration of 41 seconds occurred.

PVMBG advises against any activity in the southeastern sector along Besuk Kobokan, 13 kilometers from the peak (eruption center). Beyond that distance, the public is advised not to engage in activities within 500 meters from the riverbank (river border) along Besuk Kobokan as there is a potential for expansion of hot clouds and lava flows up to 17 kilometers from the peak.

Throughout 2026, MAGMA Indonesia has recorded 63 volcanic eruptions across Indonesia. Mount Semeru in East Java has erupted the most, with 37 eruptions.

(Read: North Sumatra Flood-Landslide Update: 116 People Died, Here are the Details)