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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

Moment tensors for all events with moment magnitudes (Mw) exceeding 5.0 and detected near Nabro during June 2011 and recorded in the Global Centroid Moment Tensor (gCMT) catalogue (Dziewonski et al. 1981; Ekström and G.M. and Dziewonski, A.M. 2012). The plots show the full moment tensor of each event, with grey lines showing the fault planes of the double-couple component of the moment tensor. Strike, dip and rake of the two nodal planes are indicated
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Fig13: Moment tensors for all events with moment magnitudes (Mw) exceeding 5.0 and detected near Nabro during June 2011 and recorded in the Global Centroid Moment Tensor (gCMT) catalogue (Dziewonski et al. 1981; Ekström and G.M. and Dziewonski, A.M. 2012). The plots show the full moment tensor of each event, with grey lines showing the fault planes of the double-couple component of the moment tensor. Strike, dip and rake of the two nodal planes are indicated

Mentions: Lastly, the normal fault strikes at 320° N, slips by 0.7 m, has a dip angle of 55° and extends from 0.8 km down to 3.2 km depth. The seismic moment associated with this fault is 4.3 × 1017 N m, which is equivalent to an Mw 5.8 earthquake (assuming a shear modulus of 3.3 × 1010 Pa). This is comparable to the sum of the two most energetic earthquakes that occurred on the day of peak seismic activity on 12 June, at 20:32 and 21:03 UTC, with magnitudes Mw 5.6 and Mw 5.4, respectively (2.91 × 1017 and 1.42 × 1017 N m according to gCMT). The focal mechanisms of these two earthquakes indicate normal faulting striking 280–290° N, albeit with a substantial non-double-couple component (Fig. 13). Given the uncertainties in the analysis, this is broadly consistent with the 320° N direction determined from our interferometric SAR analysis.Fig. 13


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)

Moment tensors for all events with moment magnitudes (Mw) exceeding 5.0 and detected near Nabro during June 2011 and recorded in the Global Centroid Moment Tensor (gCMT) catalogue (Dziewonski et al. 1981; Ekström and G.M. and Dziewonski, A.M. 2012). The plots show the full moment tensor of each event, with grey lines showing the fault planes of the double-couple component of the moment tensor. Strike, dip and rake of the two nodal planes are indicated
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4562108&req=5

Fig13: Moment tensors for all events with moment magnitudes (Mw) exceeding 5.0 and detected near Nabro during June 2011 and recorded in the Global Centroid Moment Tensor (gCMT) catalogue (Dziewonski et al. 1981; Ekström and G.M. and Dziewonski, A.M. 2012). The plots show the full moment tensor of each event, with grey lines showing the fault planes of the double-couple component of the moment tensor. Strike, dip and rake of the two nodal planes are indicated
Mentions: Lastly, the normal fault strikes at 320° N, slips by 0.7 m, has a dip angle of 55° and extends from 0.8 km down to 3.2 km depth. The seismic moment associated with this fault is 4.3 × 1017 N m, which is equivalent to an Mw 5.8 earthquake (assuming a shear modulus of 3.3 × 1010 Pa). This is comparable to the sum of the two most energetic earthquakes that occurred on the day of peak seismic activity on 12 June, at 20:32 and 21:03 UTC, with magnitudes Mw 5.6 and Mw 5.4, respectively (2.91 × 1017 and 1.42 × 1017 N m according to gCMT). The focal mechanisms of these two earthquakes indicate normal faulting striking 280–290° N, albeit with a substantial non-double-couple component (Fig. 13). Given the uncertainties in the analysis, this is broadly consistent with the 320° N direction determined from our interferometric SAR analysis.Fig. 13

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