Warning! Mount Semeru Erupts Again Tonight (Thursday, December 18, 2025)

Mount Semeru in East Java erupted again on Thursday (December 18, 2025) at 09:18 PM WIB. In the last week, Mount Semeru has erupted 24 times.

Based on eruption information from the Center for Volcanology and Geological Hazard Mitigation (PVMBG) via the MAGMA Indonesia application, the height of the ash column was observed to reach None meters above the peak (None meters above sea level).

Visual eruption was not observed. The eruption was recorded on a seismograph with a maximum amplitude of 22 millimeters and a duration of 115 seconds.

(Read: Countries with the Most Active Volcanoes in the World, Indonesia Ranks First)

According to the MAGMA Indonesia volcano activity report, Mount Semeru's activity level is at Level III (Alert). Seismic observations on December 18, 2025, from 12:00 PM to 06:00 PM WIB showed 37 eruption/explosion earthquakes with amplitudes of 10-22 millimeters and earthquake durations of 63-134 seconds.

Additionally, there was 1 rockfall earthquake with an amplitude of 10 mm and an earthquake duration of 75 seconds, and 1 exhalation earthquake with an amplitude of 8 millimeters and an earthquake duration of 30 seconds.

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

Throughout 2025, MAGMA Indonesia has recorded 7,392 volcanic eruptions across Indonesia. Mount Semeru in East Java had the most eruptions, with 3,048 recorded.

(Read: Trends in Volcanic Eruptions in Recent Years)