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Seismicity of the central Afar rift and implications for Tendaho dam hazards

Seismicity of the central Afar rift and implications for Tendaho dam hazards
Seismicity of the central Afar rift and implications for Tendaho dam hazards
Temporary broadband seismic networks deployed from 2007 to 2011 around the Afar triple junction of the East African Rift System provide insights into seismicity patterns of the actively deforming crust around the 1.86 km3 impounded lake system behind the Tendaho dam. The observed seismicity correlates well with the active magmatic centres around central Afar. The area around the dam site is characterized by a network of intersecting NNE- and NW-trending faults. Seismicity clusters observed in the specified time interval indicate that both fault sets are active and are potential sources of seismogenic hazards. The dam neighbourhood is naturally active and it is a challenge to associate the observed seismic activity to either a change in magmato-tectonic conditions or attribute it to the influence of reservoir load. It is evident that the dam region experiences high levels of seismic and volcano-tectonic unrest, regardless of the origin of the activity. The spatial overlap of narrow zones of crustal seismicity and upper mantle low velocity zones observed in S-wave tomography models suggests that melt production zones guide the distribution of strain during continental rupture. Given its volcanically and seismically active setting, the Tendaho dam site and the surrounding region require continuous monitoring for the safety of downstream populations and development infrastructures in the Afar National Regional State of Ethiopia.
0305-8719
341-354
Ayele, A.
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Ebinger, C.J.
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van Alstyne, C.
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Keir, D.
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Nixon, C.W.
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Belachew, M.
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Hammond, J.O.S.
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Wright, T.J.
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Ayele, A.
2a0d90e9-a4be-4484-9301-5c4df46f9407
Ferguson, D.J.
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Kidane, T.
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Vye-Brown, C.
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Ayele, A.
2a0d90e9-a4be-4484-9301-5c4df46f9407
Ebinger, C.J.
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van Alstyne, C.
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Keir, D.
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Nixon, C.W.
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Belachew, M.
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Hammond, J.O.S.
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Wright, T.J.
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Ayele, A.
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Ferguson, D.J.
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Kidane, T.
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Vye-Brown, C.
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Ayele, A., Ebinger, C.J., van Alstyne, C., Keir, D., Nixon, C.W., Belachew, M. and Hammond, J.O.S. , Wright, T.J., Ayele, A., Ferguson, D.J., Kidane, T. and Vye-Brown, C. (eds.) (2016) Seismicity of the central Afar rift and implications for Tendaho dam hazards. Geological Society London Special Publications, 420, 341-354. (doi:10.1144/SP420.9).

Record type: Article

Abstract

Temporary broadband seismic networks deployed from 2007 to 2011 around the Afar triple junction of the East African Rift System provide insights into seismicity patterns of the actively deforming crust around the 1.86 km3 impounded lake system behind the Tendaho dam. The observed seismicity correlates well with the active magmatic centres around central Afar. The area around the dam site is characterized by a network of intersecting NNE- and NW-trending faults. Seismicity clusters observed in the specified time interval indicate that both fault sets are active and are potential sources of seismogenic hazards. The dam neighbourhood is naturally active and it is a challenge to associate the observed seismic activity to either a change in magmato-tectonic conditions or attribute it to the influence of reservoir load. It is evident that the dam region experiences high levels of seismic and volcano-tectonic unrest, regardless of the origin of the activity. The spatial overlap of narrow zones of crustal seismicity and upper mantle low velocity zones observed in S-wave tomography models suggests that melt production zones guide the distribution of strain during continental rupture. Given its volcanically and seismically active setting, the Tendaho dam site and the surrounding region require continuous monitoring for the safety of downstream populations and development infrastructures in the Afar National Regional State of Ethiopia.

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Geological Society, London, Special Publications-2015-Ayele-SP420.9.pdf - Other
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e-pub ahead of print date: July 2015
Published date: 2016
Organisations: Geology & Geophysics

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Local EPrints ID: 377888
URI: https://eprints.soton.ac.uk/id/eprint/377888
ISSN: 0305-8719
PURE UUID: 21c63c7d-575b-44b1-afeb-fadca65eb973
ORCID for D. Keir: ORCID iD orcid.org/0000-0001-8787-8446

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Date deposited: 10 Jun 2015 10:20
Last modified: 15 Aug 2019 00:38

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Contributors

Author: A. Ayele
Author: C.J. Ebinger
Author: C. van Alstyne
Author: D. Keir ORCID iD
Author: C.W. Nixon
Author: M. Belachew
Author: J.O.S. Hammond
Editor: T.J. Wright
Editor: A. Ayele
Editor: D.J. Ferguson
Editor: T. Kidane
Editor: C. Vye-Brown

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