Volcanic activity at Mount Semeru in East Java was observed to have increased significantly on Wednesday (1/7/2026). Based on data from the Mount Semeru Observation Post, a total of 15 eruptions were recorded within a six-hour period, specifically from 06:00 to 12:00 WIB.
Sigit Rian Alfian, an officer at the Mount Semeru Observation Post, confirmed that the eruptions spewed volcanic ash columns up to a height of 1,200 meters above the summit. The observed ash material was of moderate intensity, dominated by white to gray colors, and was observed moving towards the south and southeast.
In response to this increased activity, authorities issued a strict warning to the public not to conduct any activities within a 13-kilometer radius from the eruption center. This step was taken to anticipate potential dangers threatening residents' safety.
In addition to the threat of pyroclastic flows, residents living around the slopes are also urged to increase vigilance against potential lava flows and cold lahar floods. This threat is particularly potential along river channels originating in the summit area of Mount Semeru.
