Indonesia Raises Mount Semeru Alert to Highest After Eruptions

Indonesian authorities raised the alert level for Mount Semeru to its highest on Wednesday after the volcano unleashed a series of eruptions in East Java province, prompting evacuations of thousands of residents and aviation warnings.

The eruptions began early in the morning, with the first blast recorded at 4:10 a.m. local time, followed by additional activity at 5:09 a.m. and 6:05 a.m., according to Mukdas Sofian, an officer at the Mount Semeru Observation Post. Seismographs captured the initial eruption with a maximum amplitude of 22 millimeters and a duration of 142 seconds, while plumes of ash reached heights of up to 800 meters above the summit. Later in the day, activity continued with avalanches of hot ash, rocks, lava, and gas traveling as far as 7 kilometers down the slopes, and ash columns rising 2 kilometers into the air, the Geology Agency reported. Pyroclastic flows extended up to 8.5 kilometers from the peak, directed northward by prevailing winds.

No casualties have been reported, but officials expanded exclusion zones to keep people at least 5 miles from the crater. The alert level was escalated twice during the day, from the third-highest to the maximum of...