Report on Egon (Indonesia) — 2 February-8 February 2005
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 2 February-8 February 2005
Managing Editor: Gari Mayberry
Please cite this report as:
Global Volcanism Program, 2005. Report on Egon (Indonesia). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 2 February-8 February 2005. Smithsonian Institution and US Geological Survey.
8.676°S, 122.455°E; summit elev. 1661 m
All times are local (unless otherwise noted)
An eruption at Egon on 6 February at 0103 led DVGHM to raise the Alert Level to 4 (the highest level) on the following day. The eruption was preceded by an increase in tremor, and consisted of the ejection of "glowing lava" and lapilli-sized material deposited on the volcano's S flank. An eruption occurred on 7 February at 1302 that was similar in size to the 6 February eruption. Before and after the 7 February eruption there was a strong scent of sulfur in the villages of Hebing and Hale. One villager was knocked unconscious due to the gas. All of the vegetation along a fissure on the volcano's S flank had died, also indicating that there was a strong gas emission.
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.