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MODIS images of the Ethiopian eruption 7 November 2008

Posted by admin in activity reports, Africa, Dalaffilla, eruptions, Ethiopia.
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[This is an image-heavy post, so most of it is under the cut. Click on ‘more’ below, or on the title above, to view the whole thing.]

Except for Figure 1, the images below come from the Moderate Resolution Imaging Spectroradiometer (MODIS) carried aboard NASA’s Terra and Aqua satellites. The Hawaii Institute of Geophysics and Planetology (HIGP) at the University of Hawaii has developed an automatic system that uses the infrared satellite imagery from MODIS to plot thermal anomalies in near real-time, and publishes the results on its hotspots website. The detection of thermal anomalies – hotspots – is of course one of the fundamental tools of volcano monitoring. Starting at the HIGP’s main global thermal alerts page, you can click on the part of the globe you are interested in (or select regions from a drop-down menu, or enter latitude and longitude directly) and zoom in progressively to acquire more detailed views. This post features MODIS images of the recent eruption in north-eastern Ethiopia generated by the HIGP system.

The first map below is an overview of volcanoes the Afar region of north-eastern Ethiopia (as registered by the Global Volcanism Program) from Google Earth, for reference. Below are screen captures from the Hawaii thermal alerts website, showing MODIS data for this region during the period 2-6 November 2008. This data shows the development of the hotspot associated with the eruption of 3 November, and would seem to support the contention that Dalaffilla is the volcano responsible. (Click on ‘more’ to see the MODIS images, which are under the cut.)

Figure 1. Volcanoes of the Afar region of north-eastern Ethiopia (Google Earth)
Figure 1. Volcanoes of north-eastern Ethiopia, created using Google Earth with the ‘volcanoes’ layer enabled. This layer integrates information from the Global Volcanism Program.

Figure 2. NASA MODIS image for the Afar region, 2 November 2008 (Hawaii Institute of Geophysics and Planetology)
Figure 2. MODIS image for the Afar region, 2 November 2008. Nothing happening, but this gives a good sense of the terrain. In the centre of the image, running SE to NW, is the Danakil Depression with the volcanic Erta Ale ridge forming a kind of inland island in the middle. Erta Ale volcano itself is marked just below right of centre, and the phreatic explosion crater Dallol, formed in 1926, is marked top left.

Figure 3. NASA MODIS image for the Afar region, 3 November 2008 (Hawaii Institute of Geophysics and Planetology)
Figure 3. Image from 3 November 2008. Eruption under way, with the presence of a sizeable heat source: the identification with Dalaffilla seems credible. A smaller hot-spot, interestingly, appears about 20km east of the main event.

Figure 4. NASA MODIS image for the Afar region, 4 November 2008 (Hawaii Institute of Geophysics and Planetology)
Figure 4. Image from 4 November 2008. Indications of lava on the eastern flanks of the ridge.

Figure 5. NASA MODIS image for the Afar region, 5 November 2008 (Hawaii Institute of Geophysics and Planetology)
Figure 5. Image from 5 November 2008.

Figure 6. NASA MODIS image for the Afar region, 6 November 2008 (Hawaii Institute of Geophysics and Planetology)
Figure 6. The situation on 6 November 2008.

Sequence of NASA MODIS images for the Afar region, 2-6 November 2008 (Hawaii Institute of Geophysics and Planetology)
Figure 7. Cumulative image of hotspot development, 2-6 November 2008. Figures 2-6 above are reduced from the originals, but these detail views are at full size.

UPDATE: see the valuable comment from Activolcans below, regarding the identification of the source of this eruption, with some good reasons for thinking it is Alu rather than Dalaffilla.

Viewing the Ethiopia category will bring up previous posts from The Volcanism Blog on this eruption.

News
Ethiopia researchers observe nation’s largest volcanic eruption – Bloomberg, 6 November 2008

Information
Global Volcanism Program: Dalaffilla – information about Dalaffilla (0201-07=)
Global Volcanism Program: volcanoes of Africa (northeastern) and the Red Sea – regional list of volcanoes from the Global Volcanism Program

The Volcanism Blog

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Comments

1. Activolcans - 7 November 2008

Hello to the very usefull and interesting Volcanism Blog!
The localisation of the eruption vent is very difficult!-)
The main fact that makes me think that the Alu is eruption vent is, finally, the profile of the two volcanoes: Alu volcano is a basaltic Shield volcano, hightly fractured, with important fumarolic activity long time before the eruption (cf GVN). The Dallafilla volcano is a small silicic stravolcano only built by evoluted lavas.
Moreover, in the pictures above, the source of the thermal anomaly seem to be in an area just north of Dallafilla, between this one and Alu volcano, what give more difficulties to locate precisly the active vent!
Only field trip or high resolution satellite pictures will give the correct vent finally…

Best regards to the Volcanism Blog

2. Ron Schott - 7 November 2008

I’m of the same opinion as Activolcans. The location of the hotspot seems to me to be centered slightly east of the main line of volcanoes in the Erta Ale range, consistent with the location of Alu. Furthermore, the descriptions of the volcanoes seems more consistent with Alu’s eruptive style.

Anyhow, my best guess, from the evidence I’ve seen here in Kansas, is that this eruption is more consistent with a source at Alu than Dalaffilla.


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