Mount Semeru Erupts Again Tonight (Wednesday, August 20, 2025)

Mount Semeru in East Java erupted again on Wednesday (August 20, 2025) at 11:26 PM WIB. In the last week, Mount Semeru has erupted 17 times.

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

The visual eruption was not observed. The eruption was recorded on a seismograph with a maximum amplitude of 22 millimeters and a duration of 127 seconds.

(Read: Trends in Volcanic Eruptions in Recent Years)

According to the MAGMA Indonesia volcano activity report, Mount Semeru's activity level is at Level II (Alert). Seismic observations on August 20, 2025, from 00:00-23:59 WIB showed 52 eruption tremors/earthquakes with an amplitude of 11-22 millimeters and a duration of 41-238 seconds.

Subsequently, there were 14 exhalation tremors with an amplitude of 3-9 millimeters and a duration of 24-64 seconds, and 1 harmonic tremor with an amplitude of 3 millimeters and a duration of 267 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 from the riverbanks (river border) along Besuk Kobokan as there is potential for expansion of hot clouds and lava flows up to 13 kilometers from the peak.

Throughout 2025, MAGMA Indonesia has recorded 5,712 volcanic eruptions across Indonesia. Mount Semeru in East Java had the most eruptions, with 2,292 occurrences.

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