Report on Agung (Indonesia) — 6 December-12 December 2017
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 6 December-12 December 2017
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2017. Report on Agung (Indonesia). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 6 December-12 December 2017. Smithsonian Institution and US Geological Survey.
8.343°S, 115.508°E; summit elev. 2997 m
All times are local (unless otherwise noted)
Based on BNPB and PVMBG reports, the eruption at Agung continued during 6-12 December, with high seismicity and nighttime crater incandescence often visible. On 8 December at 0759 an event generated a dense ash plume that rose 2.1 km above the crater rim and drifted W. Minor amounts of ash were deposited on the flanks, and lapilli was reported in Temakung. An ash plume rose 3 km at 1457. The number of evacuees on 10 December was 70,079 (spread out in 237 shelters). Ash plumes rose as high as 2 km. Lahars were observed in a drainage originating on the flanks of Agung. An explosion at 0549 on 11 December generated a dense ash plume that rose 2.5 km and drifted W and NW. Multiple ash-plume events were observed during 11-12 December, with plumes rising 1.5 km above the crater rim. The Alert Level remained at 4 (on a scale of 1-4), and the exclusion zones continued at a general 8-km radius and 10 km in the NNE, SE, S, and SW directions.
Geologic Background. Symmetrical Agung stratovolcano, Bali's highest and most sacred mountain, towers over the eastern end of the island. The volcano, whose name means "Paramount," rises above the SE caldera rim of neighboring Batur volcano, and the northern and southern flanks extend to the coast. The summit area extends 1.5 km E-W, with the high point on the W and a steep-walled 800-m-wide crater on the E. The Pawon cone is located low on the SE flank. Only a few eruptions dating back to the early 19th century have been recorded in historical time. The 1963-64 eruption, one of the largest in the 20th century, produced voluminous ashfall along with devastating pyroclastic flows and lahars that caused extensive damage and many fatalities.