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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.


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a Raw vertical component seismogram from station KOZE, 120 km from Nabro volcano. b Spectrogram from station KOZE. c Composite plot showing RSAM at stations KOZE (blue) and FAME (yellow), SO2 emission rate computed from OMI data (red) and infrasound signal recorded at the Nairobi station (green). SO2 emission rates were derived using a plume traverse technique (e.g. Theys et al. 2013), assuming SO2 advection in a constant wind field, with wind speed derived from a trajectory model. The magnitude and temporal variation of our OMI-based SO2 fluxes are broadly consistent with analyses of other satellite SO2 measurements for Nabro (Theys et al. 2013). The dashed vertical line indicates the eruption onset (20:27–20:42) estimated from SEVERI images
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Fig8: a Raw vertical component seismogram from station KOZE, 120 km from Nabro volcano. b Spectrogram from station KOZE. c Composite plot showing RSAM at stations KOZE (blue) and FAME (yellow), SO2 emission rate computed from OMI data (red) and infrasound signal recorded at the Nairobi station (green). SO2 emission rates were derived using a plume traverse technique (e.g. Theys et al. 2013), assuming SO2 advection in a constant wind field, with wind speed derived from a trajectory model. The magnitude and temporal variation of our OMI-based SO2 fluxes are broadly consistent with analyses of other satellite SO2 measurements for Nabro (Theys et al. 2013). The dashed vertical line indicates the eruption onset (20:27–20:42) estimated from SEVERI images

Mentions: While only ten earthquakes were recorded between 12 and 17 June, RSAM analysis of seismograms from the regional stations indicates sustained tremor (Fig. 8a). Spectrograms for the closest stations, KOZE and FAME, reveal a signal dominated by energy at frequency bands <2 Hz (Fig. 8b). The tremor was very high on the first day of the eruption but reduced during the next 2 days. On 16 June, the tremor almost stopped, but it picked up abruptly with the onset of a second period of intense seismicity on 17 June. After this, tremor persisted until 14 July with many fluctuations (Fig. 8c). The tremor was observed at many stations with different azimuths precluding interpretation of the observed signal as a path effect (e.g. Cote et al. 2010). For the period 18 June to 17 September, we located 93 events (43 % of the total events in our analysis). Events were detected on most days, with 3 days marked by earthquakes sized >ML 4.Fig. 8


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)

a Raw vertical component seismogram from station KOZE, 120 km from Nabro volcano. b Spectrogram from station KOZE. c Composite plot showing RSAM at stations KOZE (blue) and FAME (yellow), SO2 emission rate computed from OMI data (red) and infrasound signal recorded at the Nairobi station (green). SO2 emission rates were derived using a plume traverse technique (e.g. Theys et al. 2013), assuming SO2 advection in a constant wind field, with wind speed derived from a trajectory model. The magnitude and temporal variation of our OMI-based SO2 fluxes are broadly consistent with analyses of other satellite SO2 measurements for Nabro (Theys et al. 2013). The dashed vertical line indicates the eruption onset (20:27–20:42) estimated from SEVERI images
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Related In: Results  -  Collection

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Fig8: a Raw vertical component seismogram from station KOZE, 120 km from Nabro volcano. b Spectrogram from station KOZE. c Composite plot showing RSAM at stations KOZE (blue) and FAME (yellow), SO2 emission rate computed from OMI data (red) and infrasound signal recorded at the Nairobi station (green). SO2 emission rates were derived using a plume traverse technique (e.g. Theys et al. 2013), assuming SO2 advection in a constant wind field, with wind speed derived from a trajectory model. The magnitude and temporal variation of our OMI-based SO2 fluxes are broadly consistent with analyses of other satellite SO2 measurements for Nabro (Theys et al. 2013). The dashed vertical line indicates the eruption onset (20:27–20:42) estimated from SEVERI images
Mentions: While only ten earthquakes were recorded between 12 and 17 June, RSAM analysis of seismograms from the regional stations indicates sustained tremor (Fig. 8a). Spectrograms for the closest stations, KOZE and FAME, reveal a signal dominated by energy at frequency bands <2 Hz (Fig. 8b). The tremor was very high on the first day of the eruption but reduced during the next 2 days. On 16 June, the tremor almost stopped, but it picked up abruptly with the onset of a second period of intense seismicity on 17 June. After this, tremor persisted until 14 July with many fluctuations (Fig. 8c). The tremor was observed at many stations with different azimuths precluding interpretation of the observed signal as a path effect (e.g. Cote et al. 2010). For the period 18 June to 17 September, we located 93 events (43 % of the total events in our analysis). Events were detected on most days, with 3 days marked by earthquakes sized >ML 4.Fig. 8

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