Report on Egon (Indonesia) — 9 April-15 April 2008
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 9 April-15 April 2008
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2008. Report on Egon (Indonesia). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 9 April-15 April 2008. Smithsonian Institution and US Geological Survey.
8.676°S, 122.455°E; summit elev. 1661 m
All times are local (unless otherwise noted)
CVGHM reported that white plumes from Egon continued to rise to an altitude of 1.8 km (5,900 ft) a.s.l. during 4-14 April. A peak in seismicity was reached during 6-7 April and then declined significantly during 7-15 April. On 15 April, a phreatic explosion produced an ash plume that rose to an altitude of 5.7 km (18,700 ft) a.s.l. and drifted about 25 km W, reaching the town of Maumere. A team of emergency personnel in the closest village to the explosion reported that about 600 people evacuated. CVGHM raised the Alert Level to 3 (on a scale of 1-4).
Geologic Background. Gunung Egon, also known as Namang, sits astride the narrow waist of eastern Flores Island. The barren, sparsely vegetated summit region has a 350-m-wide, 200-m-deep crater that sometimes contains a lake. Other small crater lakes occur on the flanks. A lava dome forms the southern summit. Solfataric activity occurs on the crater wall and rim and on the upper S flank. Reports of historical eruptive activity prior to explosive eruptions beginning in 2004 were inconclusive. A column of "smoke" was often observed above the summit during 1888-1891 and in 1892. Strong "smoke" emission in 1907 reported by Sapper (1917) was considered by the Catalog of Active Volcanoes of the World (Neumann van Padang, 1951) to be an historical eruption, but Kemmerling (1929) noted that this was likely confused with an eruption on the same date and time from Lewotobi Lakilaki.