Large SO2 plume from Erta Ale volcano

By HansPeter Roesli and Jochen Kerkmann (EUMETSAT)

On 3 November 2008 a volcanic eruption occurred in a range of volcanoes in northern Ethiopia, called the Erta Ale range. According to the HRV channel of Meteosat-9 (see 13:00 UTC image ) the eruption started between 12:45 UTC and 13:00 UTC and can be located in the area of the volcanic cones Alu and Dalafilla. Thirteen months earlier, on 30 September 2007, nearby Jebel Al-Tair erupted in the southern Red Sea.

The initial phase of the 'Erta Ale' eruption can be well observed with the SEVIRI IR8.7 channel using the Volcanic Ash RGB product (Figure 2). The light-green, high-level SO₂ plumes (one exposed and one hidden under cloud streaks) and the black ash plume (mixed with ice particles by this time) result from the start of the eruption. The low-level SO₂ plume, on the other hand, started to be ejected only some three hours later. However, the IR8.7 channel loses its capability to detect SO₂ on 4 November over the sandy soils of Yemen and Oman, while some SO₂ continues to be blown from the volcano to the Red Sea (see Figure 1).

Thanks to the presence of relatively dry air ahead of humid air, marked by extensive cloudiness over Saudi Arabia, the evolution of the high-level SO₂ plume is visible on 4 and 5 November in the Meteosat-9 Airmass RGB product that uses, among other channels, the WV7.3 channel (see Animation, 3 Nov 12:30 UTC–5 Nov 12:00 UTC). The time sequence of the Airmass RGB shows pink coloured SO₂ plumes moving from Yemen to Oman and fading by noon on 5 November. The SO₂ signal (1284cm^-1–1344cm^-1) extracted from Metop-A IASI data over the mid-morning and early-night orbit the same day confirms the presence of SO₂ (see IASI-SEVIRI comparison ). Similarly, the SO₂ product extracted from the mid-morning orbits of Metop-A GOME-2 (see SO₂ Vertical Column Density products, credit: DLR) identifies an SO₂ patch in the same area.

Additional content

Lava Flow from Erta Ale Range, Ethiopia (NASA Earth Observatory)