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Report on Slamet (Indonesia) — November 1989


Scientific Event Alert Network Bulletin, vol. 14, no. 11 (November 1989)
Managing Editor: Lindsay McClelland.

Slamet (Indonesia) Increased seismicity and gas emission

Please cite this report as:

Global Volcanism Program, 1989. Report on Slamet (Indonesia) (McClelland, L., ed.). Scientific Event Alert Network Bulletin, 14:11. Smithsonian Institution. https://doi.org/10.5479/si.GVP.SEAN198911-263180



7.242°S, 109.208°E; summit elev. 3428 m

All times are local (unless otherwise noted)

Increased seismicity (table 1) and gas emission have been observed at Slamet since the second week in October. A white plume rose as much as 300 m, compared to 100-150 m the previous week. Geologists noted that a small eruption could occur at any time. The alert level has been increased and local officials have been notified. Slamet's most recent activity was a weak 30-hour Strombolian eruption 12-13 July [1988], preceded by tremor that began at 1145. No casualties were reported.

Table 1. Seismicity recorded at Slamet, 7-10 October 1989. S-P of A-type events is 1.5-4 seconds. Courtesy of VSI.

Seismicity A-type B-type Degassing
07 Oct 1989 -- 1 11
08 Oct 1989 -- -- 30
09 Oct 1989 25 18 200
10 Oct 1989 200 10 11

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.

Information Contacts: VSI.