CVGHM reported that incandescence had been visible 14 times in May and there were ash eruptions reaching 150-1,500 m above Slamet’s summit that drifted NW and W. White plumes were typically visible 50-800 m above the summit in May and June. There were 14 moderate ash eruptions during 15-30 June that generated plumes 500-1,400 m above the summit and drifted N and W. Incandescence was visible three times in June. During 1-2 July, there were 17 moderate ash plumes that generated plumes 300-1,200 m above the summit that drifted N and W. Alert Level 2 was maintained and visitors and tourists were prohibited from approaching the crater within a radius of 2 km.

Geological Summary. Slamet, Java's second highest volcano at 3428 m and one of its most active, has a cluster of about three dozen cinder cones on its lower SE-NE flanks and a single cinder cone on the western flank. It is composed of two overlapping edifices, an older basaltic-andesite to andesitic volcano on the west and a younger basaltic to basaltic-andesite one on the east. Gunung Malang II cinder cone on the upper E flank on the younger edifice fed a lava flow that extends 6 km E. Four craters occur at the summit of Gunung Slamet, with activity migrating to the SW over time. Historical eruptions, recorded since the 18th century, have originated from a 150-m-deep, 450-m-wide, steep-walled crater at the western part of the summit and have consisted of explosive eruptions generally lasting a few days to a few weeks.

Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)