Quantitative analysis of faulting in the Danakil Depression Rift of Afar: the importance of faulting in the final stages of magma-rich rifting
File(s)Tectonics - 2023 - Hurman.pdf (7.12 MB)
Published version
Author(s)
Type
Journal Article
Abstract
Magmatic intrusion and faulting both accommodate crustal extension in magma-rich rifts. However, quantitative constraints on the contribution of faulting to total extension and along-rift variations of faulting during the final stages of break-up are lacking. We targeted the Danakil Depression (Afar, Ethiopia) to conduct a quantitative, high-resolution study of fault activity and interaction in a magma-rich rift near break-up. Quantitative analysis of >500 rift axis faults, identified using remote sensing data (satellite imagery, DEMs), shows an increase in fault density, length and connectivity away from magmatic segments. Kinematic and earthquake focal mechanism data demonstrate a transition from transtensional opening in the northern and central sub-regions of the rift to oblique opening in the southern Giulietti Plain and Tat-Ali sub-regions. Oblique opening is attributed to the along-axis step between the Erta-Ale and Harak sub-regions. Integration of seismic reflection and borehole data with the mapped faults shows that extension is primarily accommodated by magmatism within the rift center, with faulting more significant towards the ends of the rift. ∼30% of crustal extension is accommodated by axial faulting in areas of low magmatism, highlighting the importance of faulting even in the final stages of magma-rich rifting. Comparing our findings with spreading ridge morphology and structure, relevant due to the rift maturity and extensive magmatism, we conclude that the Danakil Depression is in a transitional stage between continental rifting and seafloor spreading. Spatial changes in the importance of faulting and magmatism in accommodating extension, alongside rift morphology, resemble the relationships observed along spreading ridges.
Date Issued
2023-06
Date Acceptance
2023-05-17
Citation
Tectonics, 2023, 42 (6), pp.1-27
ISSN
0278-7407
Publisher
Wiley
Start Page
1
End Page
27
Journal / Book Title
Tectonics
Volume
42
Issue
6
Copyright Statement
© Wiley Periodicals LLC. The Authors.
This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
License URL
Identifier
https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2022TC007607
Publication Status
Published
Article Number
e2022TC007607
Date Publish Online
2023-05-26