Lumajang, East Java (ANTARA) - Mount Semeru, on the border of Lumajang and Malang Districts in East Java, erupted seven times within three hours on Wednesday morning, sending ash columns between 300 and 800 meters above the summit.
The first eruption occurred at 4:58 a.m., producing an ash column about 500 meters high that drifted northeast, according to observations from the Mount Semeru Observation Post.
The eruption was recorded on a seismograph with a maximum amplitude of 22 millimeters and a duration of 138 seconds, the observation post reported.
The second eruption followed at 6:10 a.m., with an ash column reaching approximately 700 meters above the summit, said Liswanto, an officer at the observation post.
The third eruption occurred at 6:56 a.m., with the ash column declining to about 300 meters and appearing white to gray with light intensity drifting northward.
A fourth eruption was recorded at 7:05 a.m., sending a white-to-gray ash column about 600 meters above the summit with moderate intensity toward the north.
The fifth and sixth eruptions occurred at 7:15 a.m. and 7:46 a.m., producing ash columns reaching about 800 meters and 400 meters above the summit, respectively.
The seventh eruption occurred at 8:02 a.m., though no visual observation was possible due to fog around the volcano.
Liswanto said Mount Semeru remains at Level III alert status, prompting the Center for Volcanology and Geological Hazard Mitigation to issue public safety restrictions.
Authorities have banned all activities within 13 kilometers of the summit in the southeastern sector along Besuk Kobokan, and within 500 meters of riverbanks beyond that zone.
Residents were also warned to avoid a five-kilometer radius around the crater and remain alert to pyroclastic flows, lava flows, and potential cold lava floods along nearby rivers.
