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First recorded eruption of Nabro volcano, Eritrea, 2011.

Goitom B, Oppenheimer C, Hammond JO, Grandin R, Barnie T, Donovan A, Ogubazghi G, Yohannes E, Kibrom G, Kendall JM, Carn SA, Fee D, Sealing C, Keir D, Ayele A, Blundy J, Hamlyn J, Wright T, Berhe S - Bull Volcanol (2015)

Bottom Line: It is also relevant in understanding the broader magmatic and tectonic significance of the volcanic massif of which Nabro forms a part and which strikes obliquely to the principal rifting directions in the Red Sea and northern Afar.The whole-rock compositions of the erupted lavas and tephra range from trachybasaltic to trachybasaltic andesite, and crystal-hosted melt inclusions contain up to 3,000 ppm of sulphur by weight.The eruption was preceded by significant seismicity, detected by regional networks of sensors and accompanied by sustained tremor.

View Article: PubMed Central - PubMed

Affiliation: School of Earth Sciences, University of Bristol, Queens Road, Bristol, BS8 1RJ UK ; Department of Earth Sciences, Eritrea Institute of Technology, PO Box 12676, Asmara, Eritrea.

ABSTRACT

We present a synthesis of diverse observations of the first recorded eruption of Nabro volcano, Eritrea, which began on 12 June 2011. While no monitoring of the volcano was in effect at the time, it has been possible to reconstruct the nature and evolution of the eruption through analysis of regional seismological and infrasound data and satellite remote sensing data, supplemented by petrological analysis of erupted products and brief field surveys. The event is notable for the comparative rarity of recorded historical eruptions in the region and of caldera systems in general, for the prodigious quantity of SO2 emitted into the atmosphere and the significant human impacts that ensued notwithstanding the low population density of the Afar region. It is also relevant in understanding the broader magmatic and tectonic significance of the volcanic massif of which Nabro forms a part and which strikes obliquely to the principal rifting directions in the Red Sea and northern Afar. The whole-rock compositions of the erupted lavas and tephra range from trachybasaltic to trachybasaltic andesite, and crystal-hosted melt inclusions contain up to 3,000 ppm of sulphur by weight. The eruption was preceded by significant seismicity, detected by regional networks of sensors and accompanied by sustained tremor. Substantial infrasound was recorded at distances of hundreds to thousands of kilometres from the vent, beginning at the onset of the eruption and continuing for weeks. Analysis of ground deformation suggests the eruption was fed by a shallow, NW-SE-trending dike, which is consistent with field and satellite observations of vent distributions. Despite lack of prior planning and preparedness for volcanic events in the country, rapid coordination of the emergency response mitigated the human costs of the eruption.

No MeSH data available.


Related in: MedlinePlus

Spaceborne optical observations of the Nabro eruption. a A 3.9-μm image of the saturation-corrected volcanic radiance extracted from SEVIRI at 15:12 UTC on 16 June, superimposed on GDEM topography for comparison. Low-to-high radiance is scaled from blue-to-red, and the final extent of the lava flow is outlined in red. Pixels covering the vent area and lava flow front are outlined in blue and purple, respectively. The time series of volcanogenic radiance for these pixels are shown in b. Note that the radiance time series are ‘spiky’ due to presence of cloud and plume. c The SEVIRI image that signals the start of the eruption (and providing the isolated spike in radiance seen late on 12 June in b, before the vent is obscured by plume). d Low-resolution images tracking the eruption onset, with bands around 4, 10 and 12 μm as RGB, respectively, in each case. Saturation of AVHRR channels results in loss of a strip of pixels, leading to the banding effect seen in some images. During period 1, the thermal anomaly is restricted to the SW pit in the Nabro caldera, while during period 2, a weak thermal anomaly around the plume margins may result from forward scattering of thermal emission from the advancing lava flow indicating breaching of the SW pit. Period 2 is associated with weak thermal anomalies in the SEVIRI time series seen in b. Period 3 follows the first break in the plume, revealing that lava has reached almost its final extent by this point. e High-resolution shortwave infrared images of the vent region during the later stages of the eruption. Red polygon marks the outline of the original SW pit
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Fig9: Spaceborne optical observations of the Nabro eruption. a A 3.9-μm image of the saturation-corrected volcanic radiance extracted from SEVIRI at 15:12 UTC on 16 June, superimposed on GDEM topography for comparison. Low-to-high radiance is scaled from blue-to-red, and the final extent of the lava flow is outlined in red. Pixels covering the vent area and lava flow front are outlined in blue and purple, respectively. The time series of volcanogenic radiance for these pixels are shown in b. Note that the radiance time series are ‘spiky’ due to presence of cloud and plume. c The SEVIRI image that signals the start of the eruption (and providing the isolated spike in radiance seen late on 12 June in b, before the vent is obscured by plume). d Low-resolution images tracking the eruption onset, with bands around 4, 10 and 12 μm as RGB, respectively, in each case. Saturation of AVHRR channels results in loss of a strip of pixels, leading to the banding effect seen in some images. During period 1, the thermal anomaly is restricted to the SW pit in the Nabro caldera, while during period 2, a weak thermal anomaly around the plume margins may result from forward scattering of thermal emission from the advancing lava flow indicating breaching of the SW pit. Period 2 is associated with weak thermal anomalies in the SEVIRI time series seen in b. Period 3 follows the first break in the plume, revealing that lava has reached almost its final extent by this point. e High-resolution shortwave infrared images of the vent region during the later stages of the eruption. Red polygon marks the outline of the original SW pit

Mentions: The time series of SEVIRI images indicates that the eruption started between 20:27 and 20:42 UTC on 12 June, i.e. shortly before midnight local time as confirmed by eyewitnesses. This is evident in Fig. 9a, b, which shows a measure of thermal radiation for two pixels, one representing the final lava flow front and the other the vent region inside the caldera. The signal is ‘spiky’ due to the intermittent presence of thick plume and cloud that obscure the hot material at the surface. Figure 9c shows the first SEVIRI image to register the eruption, showing an incipient thermal anomaly and plume, placing eruption onset between the time of acquisition of this image and its predecessor (20:42 and 20:27 UTC, respectively). While the SEVIRI images usefully reveal the structure and dispersal of the plume, the thermal anomalies on the ground are obscured until 15 June.Fig. 9


First recorded eruption of Nabro volcano, Eritrea, 2011.

Goitom B, Oppenheimer C, Hammond JO, Grandin R, Barnie T, Donovan A, Ogubazghi G, Yohannes E, Kibrom G, Kendall JM, Carn SA, Fee D, Sealing C, Keir D, Ayele A, Blundy J, Hamlyn J, Wright T, Berhe S - Bull Volcanol (2015)

Spaceborne optical observations of the Nabro eruption. a A 3.9-μm image of the saturation-corrected volcanic radiance extracted from SEVIRI at 15:12 UTC on 16 June, superimposed on GDEM topography for comparison. Low-to-high radiance is scaled from blue-to-red, and the final extent of the lava flow is outlined in red. Pixels covering the vent area and lava flow front are outlined in blue and purple, respectively. The time series of volcanogenic radiance for these pixels are shown in b. Note that the radiance time series are ‘spiky’ due to presence of cloud and plume. c The SEVIRI image that signals the start of the eruption (and providing the isolated spike in radiance seen late on 12 June in b, before the vent is obscured by plume). d Low-resolution images tracking the eruption onset, with bands around 4, 10 and 12 μm as RGB, respectively, in each case. Saturation of AVHRR channels results in loss of a strip of pixels, leading to the banding effect seen in some images. During period 1, the thermal anomaly is restricted to the SW pit in the Nabro caldera, while during period 2, a weak thermal anomaly around the plume margins may result from forward scattering of thermal emission from the advancing lava flow indicating breaching of the SW pit. Period 2 is associated with weak thermal anomalies in the SEVIRI time series seen in b. Period 3 follows the first break in the plume, revealing that lava has reached almost its final extent by this point. e High-resolution shortwave infrared images of the vent region during the later stages of the eruption. Red polygon marks the outline of the original SW pit
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Related In: Results  -  Collection

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Fig9: Spaceborne optical observations of the Nabro eruption. a A 3.9-μm image of the saturation-corrected volcanic radiance extracted from SEVIRI at 15:12 UTC on 16 June, superimposed on GDEM topography for comparison. Low-to-high radiance is scaled from blue-to-red, and the final extent of the lava flow is outlined in red. Pixels covering the vent area and lava flow front are outlined in blue and purple, respectively. The time series of volcanogenic radiance for these pixels are shown in b. Note that the radiance time series are ‘spiky’ due to presence of cloud and plume. c The SEVIRI image that signals the start of the eruption (and providing the isolated spike in radiance seen late on 12 June in b, before the vent is obscured by plume). d Low-resolution images tracking the eruption onset, with bands around 4, 10 and 12 μm as RGB, respectively, in each case. Saturation of AVHRR channels results in loss of a strip of pixels, leading to the banding effect seen in some images. During period 1, the thermal anomaly is restricted to the SW pit in the Nabro caldera, while during period 2, a weak thermal anomaly around the plume margins may result from forward scattering of thermal emission from the advancing lava flow indicating breaching of the SW pit. Period 2 is associated with weak thermal anomalies in the SEVIRI time series seen in b. Period 3 follows the first break in the plume, revealing that lava has reached almost its final extent by this point. e High-resolution shortwave infrared images of the vent region during the later stages of the eruption. Red polygon marks the outline of the original SW pit
Mentions: The time series of SEVIRI images indicates that the eruption started between 20:27 and 20:42 UTC on 12 June, i.e. shortly before midnight local time as confirmed by eyewitnesses. This is evident in Fig. 9a, b, which shows a measure of thermal radiation for two pixels, one representing the final lava flow front and the other the vent region inside the caldera. The signal is ‘spiky’ due to the intermittent presence of thick plume and cloud that obscure the hot material at the surface. Figure 9c shows the first SEVIRI image to register the eruption, showing an incipient thermal anomaly and plume, placing eruption onset between the time of acquisition of this image and its predecessor (20:42 and 20:27 UTC, respectively). While the SEVIRI images usefully reveal the structure and dispersal of the plume, the thermal anomalies on the ground are obscured until 15 June.Fig. 9

Bottom Line: It is also relevant in understanding the broader magmatic and tectonic significance of the volcanic massif of which Nabro forms a part and which strikes obliquely to the principal rifting directions in the Red Sea and northern Afar.The whole-rock compositions of the erupted lavas and tephra range from trachybasaltic to trachybasaltic andesite, and crystal-hosted melt inclusions contain up to 3,000 ppm of sulphur by weight.The eruption was preceded by significant seismicity, detected by regional networks of sensors and accompanied by sustained tremor.

View Article: PubMed Central - PubMed

Affiliation: School of Earth Sciences, University of Bristol, Queens Road, Bristol, BS8 1RJ UK ; Department of Earth Sciences, Eritrea Institute of Technology, PO Box 12676, Asmara, Eritrea.

ABSTRACT

We present a synthesis of diverse observations of the first recorded eruption of Nabro volcano, Eritrea, which began on 12 June 2011. While no monitoring of the volcano was in effect at the time, it has been possible to reconstruct the nature and evolution of the eruption through analysis of regional seismological and infrasound data and satellite remote sensing data, supplemented by petrological analysis of erupted products and brief field surveys. The event is notable for the comparative rarity of recorded historical eruptions in the region and of caldera systems in general, for the prodigious quantity of SO2 emitted into the atmosphere and the significant human impacts that ensued notwithstanding the low population density of the Afar region. It is also relevant in understanding the broader magmatic and tectonic significance of the volcanic massif of which Nabro forms a part and which strikes obliquely to the principal rifting directions in the Red Sea and northern Afar. The whole-rock compositions of the erupted lavas and tephra range from trachybasaltic to trachybasaltic andesite, and crystal-hosted melt inclusions contain up to 3,000 ppm of sulphur by weight. The eruption was preceded by significant seismicity, detected by regional networks of sensors and accompanied by sustained tremor. Substantial infrasound was recorded at distances of hundreds to thousands of kilometres from the vent, beginning at the onset of the eruption and continuing for weeks. Analysis of ground deformation suggests the eruption was fed by a shallow, NW-SE-trending dike, which is consistent with field and satellite observations of vent distributions. Despite lack of prior planning and preparedness for volcanic events in the country, rapid coordination of the emergency response mitigated the human costs of the eruption.

No MeSH data available.


Related in: MedlinePlus