Report on Erta Ale (Ethiopia) — 21 September-27 September 2005
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 21 September-27 September 2005
Managing Editor: Gari Mayberry
Please cite this report as:
Global Volcanism Program, 2005. Report on Erta Ale (Ethiopia). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 21 September-27 September 2005. Smithsonian Institution and US Geological Survey.
13.6°N, 40.67°E; summit elev. 613 m
All times are local (unless otherwise noted)
According to unconfirmed reports from local authorities, Erta Ale began erupting on 24 September after a series of earthquakes occurred along the Afar western margin on the previous day. The earthquakes, with a maximum magnitude of 5.5, were recorded at the Geophysical Observatory of Addis Ababa University. A group of geologists and geophysicists were planning to travel to the field to make observations.
Geologic Background. Erta Ale is an isolated basaltic shield that is the most active volcano in Ethiopia. The broad, 50-km-wide edifice rises more than 600 m from below sea level in the barren Danakil depression. Erta Ale is the namesake and most prominent feature of the Erta Ale Range. The volcano contains a 0.7 x 1.6 km, elliptical summit crater housing steep-sided pit craters. Another larger 1.8 x 3.1 km wide depression elongated parallel to the trend of the Erta Ale range is located SE of the summit and is bounded by curvilinear fault scarps on the SE side. Fresh-looking basaltic lava flows from these fissures have poured into the caldera and locally overflowed its rim. The summit caldera is renowned for one, or sometimes two long-term lava lakes that have been active since at least 1967, or possibly since 1906. Recent fissure eruptions have occurred on the N flank.
Source: Gezahegn Yirgu, Department of Earth Sciences, Addis Ababa University