Formation of normal faults along the axial zone of the Ethiopian Rift
The axial zone of the Ethiopian Rift is made up of Quaternary extensional fractures and normal faults. Field analysis was performed to study the mechanism of development of the normal faults. The collected data show that the normal faults (1) are subvertical at surface, (2) have dilation proportiona...
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Online Access: | http://hdl.handle.net/11590/152720 https://doi.org/10.1016/S0191-8141(02)00047-0 |
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ftunivroma3iris:oai:iris.uniroma3.it:11590/152720 2024-02-27T08:42:00+00:00 Formation of normal faults along the axial zone of the Ethiopian Rift Acocella V Korme T SALVINI, Francesco Acocella, V Korme, T Salvini, Francesco 2003 http://hdl.handle.net/11590/152720 https://doi.org/10.1016/S0191-8141(02)00047-0 eng eng info:eu-repo/semantics/altIdentifier/wos/WOS:000180789600002 volume:25 issue:4 firstpage:503 lastpage:513 numberofpages:11 journal:JOURNAL OF STRUCTURAL GEOLOGY http://hdl.handle.net/11590/152720 doi:10.1016/S0191-8141(02)00047-0 info:eu-repo/semantics/altIdentifier/scopus/2-s2.0-0347928797 info:eu-repo/semantics/article 2003 ftunivroma3iris https://doi.org/10.1016/S0191-8141(02)00047-0 2024-01-31T17:35:21Z The axial zone of the Ethiopian Rift is made up of Quaternary extensional fractures and normal faults. Field analysis was performed to study the mechanism of development of the normal faults. The collected data show that the normal faults (1) are subvertical at surface, (2) have dilation proportional to the throw, and (3) end laterally as extension fractures, that is, tension fractures which gradually decrease in dilation. The minimum measured opening of normal faults is 2 m and the maximum measured dilation of the extension fractures is 4 m. The minimum measured length of normal faults is 800 m and the maximum measured length of the extension fractures is 400 m. The collected data suggest that the normal faults nucleate from wider extension fractures in the axial zone. When the extension fractures reach critical dimensions (length 1/4 ,∼800 m and dilation 1/4 2-4 m, corresponding to a predicted depth of ∼700 m), the shear rupture behavior controls the further propagation of the fractures at depth. This mechanism has close similarities with models previously proposed for fault formation along the oceanic ridge of Iceland. This suggests common rifting processes along diverging plates, independently from the oceanic or continental nature of the lithosphere. Article in Journal/Newspaper Iceland Anagrafe della Ricerca d'Ateneo (Universitá degli studi Roma Tre) Journal of Structural Geology 25 4 503 513 |
institution |
Open Polar |
collection |
Anagrafe della Ricerca d'Ateneo (Universitá degli studi Roma Tre) |
op_collection_id |
ftunivroma3iris |
language |
English |
description |
The axial zone of the Ethiopian Rift is made up of Quaternary extensional fractures and normal faults. Field analysis was performed to study the mechanism of development of the normal faults. The collected data show that the normal faults (1) are subvertical at surface, (2) have dilation proportional to the throw, and (3) end laterally as extension fractures, that is, tension fractures which gradually decrease in dilation. The minimum measured opening of normal faults is 2 m and the maximum measured dilation of the extension fractures is 4 m. The minimum measured length of normal faults is 800 m and the maximum measured length of the extension fractures is 400 m. The collected data suggest that the normal faults nucleate from wider extension fractures in the axial zone. When the extension fractures reach critical dimensions (length 1/4 ,∼800 m and dilation 1/4 2-4 m, corresponding to a predicted depth of ∼700 m), the shear rupture behavior controls the further propagation of the fractures at depth. This mechanism has close similarities with models previously proposed for fault formation along the oceanic ridge of Iceland. This suggests common rifting processes along diverging plates, independently from the oceanic or continental nature of the lithosphere. |
author2 |
Acocella, V Korme, T Salvini, Francesco |
format |
Article in Journal/Newspaper |
author |
Acocella V Korme T SALVINI, Francesco |
spellingShingle |
Acocella V Korme T SALVINI, Francesco Formation of normal faults along the axial zone of the Ethiopian Rift |
author_facet |
Acocella V Korme T SALVINI, Francesco |
author_sort |
Acocella V |
title |
Formation of normal faults along the axial zone of the Ethiopian Rift |
title_short |
Formation of normal faults along the axial zone of the Ethiopian Rift |
title_full |
Formation of normal faults along the axial zone of the Ethiopian Rift |
title_fullStr |
Formation of normal faults along the axial zone of the Ethiopian Rift |
title_full_unstemmed |
Formation of normal faults along the axial zone of the Ethiopian Rift |
title_sort |
formation of normal faults along the axial zone of the ethiopian rift |
publishDate |
2003 |
url |
http://hdl.handle.net/11590/152720 https://doi.org/10.1016/S0191-8141(02)00047-0 |
genre |
Iceland |
genre_facet |
Iceland |
op_relation |
info:eu-repo/semantics/altIdentifier/wos/WOS:000180789600002 volume:25 issue:4 firstpage:503 lastpage:513 numberofpages:11 journal:JOURNAL OF STRUCTURAL GEOLOGY http://hdl.handle.net/11590/152720 doi:10.1016/S0191-8141(02)00047-0 info:eu-repo/semantics/altIdentifier/scopus/2-s2.0-0347928797 |
op_doi |
https://doi.org/10.1016/S0191-8141(02)00047-0 |
container_title |
Journal of Structural Geology |
container_volume |
25 |
container_issue |
4 |
container_start_page |
503 |
op_container_end_page |
513 |
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1792049379943645184 |