Mount Semeru, located on the border of Lumajang and Malang Regencies, East Java, showed increased volcanic activity again on Sunday (28/6/2026). The peak of the highest mountain on Java Island spewed a column of volcanic ash 1,000 meters above the summit, or approximately 4,676 meters above sea level, at 11:37 AM WIB.
Mount Semeru Observation Post officer Mukdas Sofian reported that the observed ash column was white to gray with thick intensity, moving toward the southeast and south sectors. This eruption phenomenon was recorded on a seismogram with a maximum amplitude of 22 mm and lasted for 170 seconds.
Officer records indicate that this eruption was part of a series of four volcanic activities that occurred throughout Sunday. The series of eruptions began at 05:35 AM WIB, followed by an eruption at 06:32 AM WIB with a column height of 500 meters, and a third eruption at 09:11 AM WIB monitored via seismograph equipment.
Currently, Mount Semeru's alert status remains at Level III (Alert). The public is advised not to conduct any activities in the southeast sector along Besuk Kobokan within a 13-kilometer radius from the eruption center. In addition, residents are prohibited from carrying out activities within 500 meters of the riverbanks along Besuk Kobokan to avoid the risk of pyroclastic flows and lahar flows, which could potentially extend up to 17 kilometers.
