Warning! Mount Semeru Erupts Again Tonight (Monday, August 18, 2025)

Mount Semeru in East Java erupted again on Monday (8/18/2025) at 10:31 PM WIB. In the past week, Mount Semeru has erupted 2 times.

Reporting 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 be around None meters above the peak or None meters above sea level.

No visual eruption was observed. The eruption was recorded on a seismograph with a maximum amplitude of 21 millimeters and a duration of 134 seconds.

(Read: Indonesia Has the Most Active Volcanoes in the World)

According to the MAGMA Indonesia volcano activity report, the activity level of Mount Semeru is at Level II (Alert). Seismicity observations on August 18, 2025, from 00:00-23:59 WIB showed 45 eruption tremors/quakes with amplitudes of 11-22 millimeters and durations of 36-221 seconds.

Furthermore, there were 4 avalanche earthquakes with amplitudes of 4-6 mm and durations of 43-81 seconds, and 8 puff earthquakes with amplitudes of 3-6 millimeters and durations of 31-53 seconds.

PVMBG urges against any activity in the southeast sector along Besuk Kobokan, as far as 8 kilometers from the peak (eruption center). Beyond that distance, the public should not engage in activities within 500 meters of the riverbanks 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 5,682 volcanic eruptions across Indonesia. Mount Semeru in East Java has erupted the most with 2,277 times.

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