Controls on early‐rift geometry: new perspectives from the Bilila‐Mtakataka fault, Malawi

Hodge, Michael ORCID: https://orcid.org/0000-0002-0754-4110, Fagereng, Ake ORCID: https://orcid.org/0000-0001-6335-8534, Biggs, Juliet and Mdala, Hassan 2018. Controls on early‐rift geometry: new perspectives from the Bilila‐Mtakataka fault, Malawi. Geophysical Research Letters 10.1029/2018gl077343

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Abstract

We use the ~110 km long Bilila‐Mtakataka fault in the amagmatic southern East African Rift, Malawi, to investigate the controls on early‐rift geometry at the scale of a major border fault. Morphological variations along the 14±8 m high scarp define six 10‐40 km long segments, which are either foliation parallel, or oblique to both foliation and the current regional extension direction. As the scarp is neither consistently parallel to foliation, nor well oriented for the current regional extension direction, we suggest the segmented surface expression is related to the local reactivation of well oriented weak shallow fabrics above a broadly continuous structure at depth. Using a geometrical model, the geometry of the best‐fitting subsurface structure is consistent with the local strain field from recent seismicity. In conclusion, within this early‐rift, pre‐existing weaknesses only locally control border fault geometry at subsurface.

Item Type:	Article
Date Type:	Published Online
Status:	Published
Schools:	Earth and Environmental Sciences
Subjects:	Q Science > QE Geology
Publisher:	American Geophysical Union (AGU)
ISSN:	0094-8276
Date of First Compliant Deposit:	26 April 2018
Date of Acceptance:	10 April 2018
Last Modified:	04 Dec 2024 23:45
URI:	https://orca.cardiff.ac.uk/id/eprint/110878

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