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Lower crustal earthquakes near the Ethiopian rift induced by magmatic processes

Lower crustal earthquakes near the Ethiopian rift induced by magmatic processes
Lower crustal earthquakes near the Ethiopian rift induced by magmatic processes
Lower crustal earthquakes are commonly observed in continental rifts at depths where temperatures should be too high for brittle failure to occur. Here we present accurately located earthquakes in central Ethiopia, covering an incipient oceanic plate boundary in the Main Ethiopian Rift. Seismicity is evaluated using the combination of exceptionally well resolved seismic structure of the crust and upper mantle, electromagnetic properties of the crust, rock geochemistry, and geological data. The combined data sets provide evidence that lower crustal earthquakes are focused in mafic lower crust containing pockets of the largest fraction of partial melt. The pattern of seismicity and distribution of crustal melt also correlates closely with presence of partial melt in the upper mantle, suggesting lower crustal earthquakes are induced by ongoing crustal modification through magma emplacement that is driven by partial melting of the mantle. Our results show that magmatic processes control not only the distribution of shallow seismicity and volcanic activity along the axis of the rift valley but also anomalous earthquakes in the lower crust away from these zones of localized strain.
1525-2027
Q0AB02
Keir, Derek
5616f81f-bf1b-4678-a167-3160b5647c65
Bastow, Ian D.
7a2698d0-d535-4462-a9a9-0e3293d2d667
Whaler, Kathryn A.
79173a4b-7496-4f23-affe-314f69f5b8ac
Daly, Eve
93199cb0-1ffe-4994-9ba1-b2883be55aaf
Cornwell, David G.
4b4c3932-e739-41b8-bdef-655bbd9a9f21
Hautot, Sophie
9e6886a0-0d8b-41ed-8530-1dd5674ab043
Keir, Derek
5616f81f-bf1b-4678-a167-3160b5647c65
Bastow, Ian D.
7a2698d0-d535-4462-a9a9-0e3293d2d667
Whaler, Kathryn A.
79173a4b-7496-4f23-affe-314f69f5b8ac
Daly, Eve
93199cb0-1ffe-4994-9ba1-b2883be55aaf
Cornwell, David G.
4b4c3932-e739-41b8-bdef-655bbd9a9f21
Hautot, Sophie
9e6886a0-0d8b-41ed-8530-1dd5674ab043

Keir, Derek, Bastow, Ian D., Whaler, Kathryn A., Daly, Eve, Cornwell, David G. and Hautot, Sophie (2009) Lower crustal earthquakes near the Ethiopian rift induced by magmatic processes. Geochemistry, Geophysics, Geosystems, 10, Q0AB02. (doi:10.1029/2009GC002382).

Record type: Article

Abstract

Lower crustal earthquakes are commonly observed in continental rifts at depths where temperatures should be too high for brittle failure to occur. Here we present accurately located earthquakes in central Ethiopia, covering an incipient oceanic plate boundary in the Main Ethiopian Rift. Seismicity is evaluated using the combination of exceptionally well resolved seismic structure of the crust and upper mantle, electromagnetic properties of the crust, rock geochemistry, and geological data. The combined data sets provide evidence that lower crustal earthquakes are focused in mafic lower crust containing pockets of the largest fraction of partial melt. The pattern of seismicity and distribution of crustal melt also correlates closely with presence of partial melt in the upper mantle, suggesting lower crustal earthquakes are induced by ongoing crustal modification through magma emplacement that is driven by partial melting of the mantle. Our results show that magmatic processes control not only the distribution of shallow seismicity and volcanic activity along the axis of the rift valley but also anomalous earthquakes in the lower crust away from these zones of localized strain.

Full text not available from this repository.

More information

Published date: 2009

Identifiers

Local EPrints ID: 175157
URI: http://eprints.soton.ac.uk/id/eprint/175157
ISSN: 1525-2027
PURE UUID: 3ce5a01e-ca6f-4af4-92a2-f41cb6be3a8f
ORCID for Derek Keir: ORCID iD orcid.org/0000-0001-8787-8446

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Date deposited: 22 Feb 2011 16:09
Last modified: 29 Oct 2019 01:42

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