Crustal and thermal structure of the Permian – Jurassic Luangwa – Lukusashi – Luano Rift, Zambia: Implications for strain localization in magma – Poor continental rifts

Matende, Kitso N.; Atekwana, Estella A.; Mickus, Kevin L.; Abdelsalam, Mohamed G.; Atekwana, Eliot A.; Evans, Robert; Nyalugwe, V.; Emishaw, Luelseged

doi:10.1016/j.jafrearsci.2020.104090

Cited by 5 publications

(9 citation statements)

References 86 publications

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Section: Tectonic and Geologic Backgroundmentioning

confidence: 99%

“…In this paper, we map the active faults in one poorly studied rift segment, the Luangwa Rift in Zambia. Although it had been thought that the Luangwa Rift is inactive (Banks et al, 1995;Matende et al, 2021;Sun et al, 2021), recent plate modelling and the evidence of Quaternary activity on the Chipola Fault (Daly et al, 2020) confirm this is an active rift system (Fig. 1).…”

Section: Introductionmentioning

confidence: 97%

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The Luangwa Rift Active Fault Database and fault reactivation along the southwestern branch of the East African Rift

et al. 2022

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Abstract. Seismic hazard assessment in slow straining regions is challenging because earthquake catalogues only record events from approximately the last 100 years, whereas earthquake recurrence times on individual faults can exceed 1000 years. Systematic mapping of active faults allows fault sources to be used within probabilistic seismic hazard assessment, which overcomes the problems of short-term earthquake records. We use Shuttle Radar Topography Mission (SRTM) data to analyse surface deformation in the Luangwa Rift in Zambia and develop the Luangwa Rift Active Fault Database (LRAFD). The LRAFD is an open-source geospatial database containing active fault traces and their attributes and is freely available at https://doi.org/10.5281/zenodo.6513691. We identified 18 faults that display evidence for Quaternary activity, and empirical relationships suggest that these faults could cause earthquakes up to Mw 8.1, which would exceed the magnitude of historically recorded events in southern Africa. On the four most prominent faults, the median height of Quaternary fault scarps varies between 12.9 ± 0.4 and 19.2 ± 0.9 m, which suggests they were formed by multiple earthquakes. Deformation is focused on the edges of the Luangwa Rift: the most prominent Quaternary fault scarps occur along the 207 km long Chipola and 142 km long Molaza faults, which are the rift border faults and the longest faults in the region. We associate the scarp on the Molaza Fault with possible surface ruptures from two 20th century earthquakes. Thus, the LRAFD reveals new insights into active faulting in southern Africa and presents a framework for evaluating future seismic hazard.

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Section: Tectonic and Geologic Backgroundmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 97%

The Luangwa Rift Active Fault Database and fault reactivation along the southwestern branch of the East African Rift

et al. 2022

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“…The Luangwa Rift was active during the Permian-Jurassic breakup of Gondwana (Daly et al, 1989;Banks et al, 1995;Matende et al, 2021) and during the Cretaceous (Daly et al, 2020). Up to 8,000 m of Permo-Traissic (ie Karoo period in southern Africa) mainly clastic sediments are unconformably capped by finer grained post-Karoo deposits (Banks et al, 1995).…”

Section: Tectonic and Geologic Backgroundmentioning

confidence: 99%

“…The Nyamadzi shear zone is a splay of the Mwembeshi shear zone and is comprised of planar, vertically dipping fabrics within a wide variety of lithologies including ultramylonitic granites, highly deformed quartzites and mafic igneous gabbros and amphibolites (Johnson et al, 2006). Daly et al (2020) found evidence that shows that the Luangwa Rift has been active during the Quaternary, whereas others suggest that rifting ceased in the Mesozoic (Banks et al, 1995;Matende et al, 2021;Sun et al, 2021). The rift is hosted in 150-160 km thick lithosphere (Priestley et al, 2018), with a crustal thickness of 41-45 km (Sun et al, 2021), and seismicity…”

Section: Tectonic and Geologic Backgroundmentioning

confidence: 99%

“…In this paper, we map the active faults in one poorly studied rift segment, the Luangwa Rift in Zambia. Although it had been thought that the Luangwa Rift is inactive (Banks et al, 1995;Matende et al, 2021;Sun et al, 2021), recent plate modelling (Wedmore et al, 2021) and the evidence of Quaternary activity on the Chipola Fault (Daly et al, 2020) confirm this is an active rift system (Figure 1). However, until now there has been no systematic map of active faults in the region.…”

Section: Introductionmentioning

confidence: 99%

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The Luangwa Rift Active Fault Database and fault reactivation along the southwestern branch of the East African Rift

Wedmore

Turner

Biggs

et al. 2022

Preprint

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Abstract. Seismic hazard assessment in slow straining regions is challenging because earthquake catalogues only record events from approximately the last 100 years, whereas earthquake recurrence times on individual faults can exceed 1,000 years. Systematic mapping of active faults allows fault sources to be used within probabilistic seismic hazard assessment, which overcomes the problems of short-term earthquake records. We use Shuttle Radar Topography Mission (SRTM) data to analyse surface deformation in the Luangwa Rift in Zambia and develop the Luangwa Rift Active Fault Database (LRAFD). The LRAFD is an open-source geospatial database containing active fault traces and their attributes and is freely available at: https://doi.org/10.5281/zenodo.6513691. We identified 18 faults that display evidence for Quaternary activity and empirical relationships suggest that these faults could cause earthquakes up to Mw 8.1, which would exceed the magnitude of historically recorded events in southern Africa. On the four most prominent faults, the median height of Late Quaternary fault scarps varies between 12.9 ± 0.4 and 19.2 ± 0.9 m, which suggests they were formed by multiple earthquakes. Deformation is focused on the edges of the Luangwa Rift: the most prominent Late Quaternary fault scarps occur along the 207 km long Chipola and 142 km long Molaza faults, which are the rift border faults and the longest faults in the region. We associate the scarp on the Molaza Fault with possible surface ruptures from two 20th Century earthquakes. Thus, the LRAFD reveals new insights into active faulting in southern Africa and presents a framework for evaluating future seismic hazard.

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Satellite gravity data for mapping lithospheric structure of Precambrian tectonic blocks in Africa: The advantages and limitations

Emishaw

Abdelsalam²

2023

Journal of African Earth Sciences

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Crustal and thermal structure of the Permian – Jurassic Luangwa – Lukusashi – Luano Rift, Zambia: Implications for strain localization in magma – Poor continental rifts

Cited by 5 publications

References 86 publications

The Luangwa Rift Active Fault Database and fault reactivation along the southwestern branch of the East African Rift

The Luangwa Rift Active Fault Database and fault reactivation along the southwestern branch of the East African Rift

The Luangwa Rift Active Fault Database and fault reactivation along the southwestern branch of the East African Rift

Satellite gravity data for mapping lithospheric structure of Precambrian tectonic blocks in Africa: The advantages and limitations

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