Report on Erta Ale (Ethiopia) — 8 December-14 December 2004
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 8 December-14 December 2004
Managing Editor: Gari Mayberry
Please cite this report as:
Global Volcanism Program, 2004. Report on Erta Ale (Ethiopia). In: Mayberry, G (ed.), Weekly Volcanic Activity Report, 8 December-14 December 2004. Smithsonian Institution and US Geological Survey.
13.6°N, 40.67°E; summit elev. 613 m
All times are local (unless otherwise noted)
During a trip to Erta Ale on 4 December, a group of scientists from SVE-SVG observed no activity in the lava lake in the volcano's South Pit crater. A solidified lava crust covered the crater floor about 15 m below the crater rim. The group also saw that new activity within North crater had produced a solidified lava bulge filling about 4/5 of the crater floor. Degassing from several small hornitos occurred in the central part of the lava bulge. During the evening, ten small incandescent vents were visible at the periphery of the lava bulge. In the morning, two plumes rose above the volcano.
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.