Comparison of dike intrusions in an incipient seafloor-spreading segment in Afar, Ethiopia: Seismicity perspectives
Oceanic crust is accreted through the emplacement of dikes at spreading ridges, but the role of dike intrusion in plate boundary deformation during continental rupture remains poorly understood. Between 2005 and 2009 the ∼70 km long Dabbahu‐Manda Hararo rift segment in Ethiopia has experienced 14 la...
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2011
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Online Access: | http://hdl.handle.net/2292/11616 https://doi.org/10.1029/2010JB007908 |
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ftunivauckland:oai:researchspace.auckland.ac.nz:2292/11616 2023-05-15T16:51:56+02:00 Comparison of dike intrusions in an incipient seafloor-spreading segment in Afar, Ethiopia: Seismicity perspectives Belachew, M Ebinger, C Cote, D Keir, D Rowland, JV Hammond, JOS Ayele, A 2011 http://hdl.handle.net/2292/11616 https://doi.org/10.1029/2010JB007908 EN eng AMER GEOPHYSICAL UNION Journal of Geophysical Research (Solid Earth) Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated. Previously published items are made available in accordance with the copyright policy of the publisher. Details obtained from: http://www.sherpa.ac.uk/romeo/issn/0148-0227/ https://researchspace.auckland.ac.nz/docs/uoa-docs/rights.htm Copyright: AMER GEOPHYSICAL UNION http://purl.org/eprint/accessRights/RestrictedAccess http://dx.doi.org/10.1029/2010JB007908 DE-FUCA RIDGE DABBAHU RIFTING EPISODE SOMALIA PLATE BOUNDARY KRAFLA CENTRAL VOLCANO KILAUEA-VOLCANO RED-SEA NORTH-ICELAND CONTINENTAL RUPTURE PROPAGATING RIFTS DYKE INTRUSIONS Journal Article 2011 ftunivauckland https://doi.org/10.1029/2010JB007908 2013-12-07T09:16:30Z Oceanic crust is accreted through the emplacement of dikes at spreading ridges, but the role of dike intrusion in plate boundary deformation during continental rupture remains poorly understood. Between 2005 and 2009 the ∼70 km long Dabbahu‐Manda Hararo rift segment in Ethiopia has experienced 14 large volume dike intrusions, 9 of which were recorded on temporary seismic arrays. A detailed comparison of the seismic characteristics of the seismically monitored dikes is presented with implications for dike intrusion processes and magmatic plumbing systems. All of the migrating swarms of earthquakes started from a <5 km radius zone at the middle of the Dabbahu‐Manda Hararo segment, and traveled northward and southward along the rift axis. Small magnitude earthquakes associated with the margins of the propagating dike tips are followed by the largest magnitude, primarily low‐frequency earthquakes. The seismic moment distributions show >80% of energy is released during the propagation phase, with minimal seismic energy release after the dike propagation ceases. We interpret that faulting and graben formation above the dikes occurs hours after the passage of the dike tip, coincident with the onset of low‐frequency earthquakes. Dike lengths show no systematic reduction in length with time, suggesting that topographic loading and stress barriers influence dike length, as well as changes in tectonic stress. The propagation velocities of all the dikes follow a decaying exponential. Northward propagating dikes had faster average velocities than those that propagated southward, suggesting preconditioning by the 2005 megadike, or ongoing heating from a subcrustal magma source north of the midsegment. Article in Journal/Newspaper Iceland University of Auckland Research Repository - ResearchSpace Krafla ENVELOPE(-16.747,-16.747,65.713,65.713) Journal of Geophysical Research 116 B6 |
institution |
Open Polar |
collection |
University of Auckland Research Repository - ResearchSpace |
op_collection_id |
ftunivauckland |
language |
English |
topic |
DE-FUCA RIDGE DABBAHU RIFTING EPISODE SOMALIA PLATE BOUNDARY KRAFLA CENTRAL VOLCANO KILAUEA-VOLCANO RED-SEA NORTH-ICELAND CONTINENTAL RUPTURE PROPAGATING RIFTS DYKE INTRUSIONS |
spellingShingle |
DE-FUCA RIDGE DABBAHU RIFTING EPISODE SOMALIA PLATE BOUNDARY KRAFLA CENTRAL VOLCANO KILAUEA-VOLCANO RED-SEA NORTH-ICELAND CONTINENTAL RUPTURE PROPAGATING RIFTS DYKE INTRUSIONS Belachew, M Ebinger, C Cote, D Keir, D Rowland, JV Hammond, JOS Ayele, A Comparison of dike intrusions in an incipient seafloor-spreading segment in Afar, Ethiopia: Seismicity perspectives |
topic_facet |
DE-FUCA RIDGE DABBAHU RIFTING EPISODE SOMALIA PLATE BOUNDARY KRAFLA CENTRAL VOLCANO KILAUEA-VOLCANO RED-SEA NORTH-ICELAND CONTINENTAL RUPTURE PROPAGATING RIFTS DYKE INTRUSIONS |
description |
Oceanic crust is accreted through the emplacement of dikes at spreading ridges, but the role of dike intrusion in plate boundary deformation during continental rupture remains poorly understood. Between 2005 and 2009 the ∼70 km long Dabbahu‐Manda Hararo rift segment in Ethiopia has experienced 14 large volume dike intrusions, 9 of which were recorded on temporary seismic arrays. A detailed comparison of the seismic characteristics of the seismically monitored dikes is presented with implications for dike intrusion processes and magmatic plumbing systems. All of the migrating swarms of earthquakes started from a <5 km radius zone at the middle of the Dabbahu‐Manda Hararo segment, and traveled northward and southward along the rift axis. Small magnitude earthquakes associated with the margins of the propagating dike tips are followed by the largest magnitude, primarily low‐frequency earthquakes. The seismic moment distributions show >80% of energy is released during the propagation phase, with minimal seismic energy release after the dike propagation ceases. We interpret that faulting and graben formation above the dikes occurs hours after the passage of the dike tip, coincident with the onset of low‐frequency earthquakes. Dike lengths show no systematic reduction in length with time, suggesting that topographic loading and stress barriers influence dike length, as well as changes in tectonic stress. The propagation velocities of all the dikes follow a decaying exponential. Northward propagating dikes had faster average velocities than those that propagated southward, suggesting preconditioning by the 2005 megadike, or ongoing heating from a subcrustal magma source north of the midsegment. |
format |
Article in Journal/Newspaper |
author |
Belachew, M Ebinger, C Cote, D Keir, D Rowland, JV Hammond, JOS Ayele, A |
author_facet |
Belachew, M Ebinger, C Cote, D Keir, D Rowland, JV Hammond, JOS Ayele, A |
author_sort |
Belachew, M |
title |
Comparison of dike intrusions in an incipient seafloor-spreading segment in Afar, Ethiopia: Seismicity perspectives |
title_short |
Comparison of dike intrusions in an incipient seafloor-spreading segment in Afar, Ethiopia: Seismicity perspectives |
title_full |
Comparison of dike intrusions in an incipient seafloor-spreading segment in Afar, Ethiopia: Seismicity perspectives |
title_fullStr |
Comparison of dike intrusions in an incipient seafloor-spreading segment in Afar, Ethiopia: Seismicity perspectives |
title_full_unstemmed |
Comparison of dike intrusions in an incipient seafloor-spreading segment in Afar, Ethiopia: Seismicity perspectives |
title_sort |
comparison of dike intrusions in an incipient seafloor-spreading segment in afar, ethiopia: seismicity perspectives |
publisher |
AMER GEOPHYSICAL UNION |
publishDate |
2011 |
url |
http://hdl.handle.net/2292/11616 https://doi.org/10.1029/2010JB007908 |
long_lat |
ENVELOPE(-16.747,-16.747,65.713,65.713) |
geographic |
Krafla |
geographic_facet |
Krafla |
genre |
Iceland |
genre_facet |
Iceland |
op_source |
http://dx.doi.org/10.1029/2010JB007908 |
op_relation |
Journal of Geophysical Research (Solid Earth) |
op_rights |
Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated. Previously published items are made available in accordance with the copyright policy of the publisher. Details obtained from: http://www.sherpa.ac.uk/romeo/issn/0148-0227/ https://researchspace.auckland.ac.nz/docs/uoa-docs/rights.htm Copyright: AMER GEOPHYSICAL UNION http://purl.org/eprint/accessRights/RestrictedAccess |
op_doi |
https://doi.org/10.1029/2010JB007908 |
container_title |
Journal of Geophysical Research |
container_volume |
116 |
container_issue |
B6 |
_version_ |
1766042060662505472 |