Mount Semeru recorded 1,263 eruptions from January 1 to June 16, 2026, making it Indonesia's most active volcano.
Data from magma.esdm.go.id shows Mount Semeru surpassing Mount Ibu, which recorded 930 eruptions, and Mount Lewotobi Laki-laki with 215 eruptions.
Volcanic smoke was seen emerging from Semeru's crater in Candipuro district, Lumajang, East Java on June 16, 2026.
The ranking is based on activity during the first six months of 2026.