Mount Semeru Erupts Twice, Sends 700-Meter Ash Column into Sky

Lumajang: Mount Semeru, straddling the border between Lumajang and Malang districts in East Java, erupted twice on Thursday morning, sending an ash column up to 700 meters above its summit, authorities said.

The latest eruption occurred at 7:20 a.m. local time, producing an ash plume that rose approximately 700 meters above the peak, or 4,376 meters above sea level, according to Mukdas Sofian, an officer at the Mount Semeru Observation Post.

“The eruption column was thick, white to gray in color, and drifted toward the southeast,” Sofian said, as quoted by Antara on Thursday, January 29, 2026.

The eruption was recorded on a seismograph with a maximum amplitude of 22 millimeters and lasted 115 seconds. It followed an earlier eruption at 4:47 a.m., which generated a 500-meter ash column and lasted 123 seconds, with a maximum amplitude of 20 millimeters.

Mount Semeru remains at Alert Level III. As a result, the Center for Volcanology and Geological Hazard Mitigation (PVMBG) has banned all activities in the southeastern sector along Besuk Kobokan, within a 13-kilometer radius from the summit.

Authorities have also advised residents to stay at least 500 meters away from riverbanks along Besuk Kobokan due to the potential for pyroclastic flows and lava flows reaching up to 17 kilometers from the crater.

“In addition, the public is prohibited from carrying out any activities within a five-kilometer radius of the summit or crater due to the risk of falling volcanic material,” Sofian said.

Residents are further urged to remain alert to the risk of pyroclastic flows, lava flows, and lahars along rivers and valleys originating from Mount Semeru, particularly Besuk Kobokan, Besuk Bang, Besuk Kembar, and Besuk Sat, as well as smaller tributaries feeding into Besuk Kobokan.