Complex Martinique intermediate-depth earthquake reactivates early Atlantic break-up structures

Mike Lindner (Lead Author), Andreas Rietbrock, Lidong Bie, Ya-jian Gao, Saskia Goes, Michael Frietsch

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Abstract

Earthquakes that rupture several faults occur frequently within the shallow lithosphere but are rarely observed for intermediate-depth events (70–300 km). On 29 November 2007, the Mw7.4 Martinique earthquake struck the Lesser Antilles Island Arc near the deep end of the Wadati-Benioff-Zone. The sparse regional seismic network of 2007 previously hampered a detailed examination of this unusually complex event. Here, we combine seismic data from different studies with regional moment tensor inversion results and 3D full-waveform modeling. We show that the earthquake is a doublet consisting of dip-slip and strike-slip motion along two oblique structures, both activated under extensional stress along the strike of the slab. Comparison with tectonic reconstructions suggests that the earthquake ruptured along a re-activated ridge-transform segment of the subducted Proto-Caribbean spreading ridge. The unprecedented resolution of the source process highlights the influence of pre-existing structures on localizing slab deformation also at intermediate-depth.
Original languageEnglish
Article numbere2024GL108922
JournalGeophysical Research Letters
Volume51
Issue number11
Early online date11 Jun 2024
DOIs
Publication statusPublished - 16 Jun 2024

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