GPS constraints on broad scale extension in the Ethiopian Highlands and Main Ethiopian Rift

Yelebe Birhanu, Rebecca Bendick, Shimeles Fisseha, Elias Lewi, Michael Floyd, Robert King, Robert Reilinger

    Research output: Contribution to journalArticlepeer-review

    Abstract

    Measurements from GPS sites spanning the Ethiopian Highlands, Main Ethiopian Rift, and Somali Platform in Ethiopia and Eritrea show that present-day finite strain rates throughout NE Africa can be approximated at the continent scale by opening on the MER. Most sites in the Ethiopian Highlands are consistent with the motion of the Nubian plate at the level of 1 mm/yr with 95% confidence. However, sites at least as far as 60 km west of the rift show higher velocities relative to the stable Nubian frame of 1–2 mm/yr, requiring a combination of localized and distributed deformation to accommodate the African extensional domain. Off-rift velocities are consistent with ongoing strain related to either high gravitational potential energy or intrusive magmatism away from midrift magmatic segments either on the western rift margin or within the Ethiopian Highlands, especially when combined with likely rheological differences between the Ethiopian Rift and Highlands. Velocities from the Somali Platform are less well determined with uncertainties and residuals from a Somali frame definition at the level of 2–3 mm/yr but without spatially correlated residuals.

    Original languageEnglish
    Pages (from-to)6844-6851
    Number of pages8
    JournalGeophysical Research Letters
    Volume43
    Issue number13
    DOIs
    StatePublished - Jul 16 2016

    Keywords

    • continental dynamics
    • East African Rift
    • Ethiopian Highlands
    • GPS

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