Ongoing tectonic subsidence in the Lesser Antilles subduction zone

This is a Preprint and has not been peer reviewed. The published version of this Preprint is available: https://doi.org/10.1093/gji/ggac192. This is version 2 of this Preprint.

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Authors

Elenora van Rijsingen, Eric Calais , Romain Jolivet, Jean-Bernard de Chabalier, Richard Robertson , Graham A Ryan, Steeve Symithe

Abstract

Geological estimates of vertical motions in the central part of the Lesser Antilles show subsidence on timescales ranging from 125.000 to 100 years, which has been interpreted to be caused by interseismic locking along the subduction megathrust. However, horizontal GNSS velocities show that the Lesser Antilles subduction interface is currently building up little to no elastic strain. Here we present new present-day vertical velocities for the Lesser Antilles islands and explore the link between short- and long-term vertical motions and their underlying processes. We find a geodetic subsidence of the Lesser Antilles island arc at 1-2 mm/yr, consistent with the ∼100-year trend derived from coral micro-atolls. Using elastic dislocation models, we show that a locked or partially-locked subduction interface would produce uplift of the island arc, opposite to the observations, hence supporting a poorly-coupled subduction. We propose that this long-term, margin-wide subsidence is controlled by slab dynamic processes, such as slab rollback. Such processes could also be responsible for the aseismic character of the subduction megathrust.

DOI

https://doi.org/10.31223/X5360D

Subjects

Earth Sciences

Keywords

Lesser Antilles, Seismotectonics, Earthquakes, earthquakes, Vertical tectonic motions, seismotectonics, subduction, subsidence, Vertical tectonic motions

Dates

Published: 2021-04-20 07:58

Last Updated: 2022-06-15 12:01

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License

CC BY Attribution 4.0 International

Additional Metadata

Data Availability (Reason not available):
The data are presented in the supporting information of this manuscript, which readers can request by contacting the corresponding author.

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