Estimation of Lesser Antilles Vertical Velocity Fields Using a GNSS-PPP Software Comparison

Sakic, Pierre; Männel, Benjamin; Bradke, Markus; Ballu, Valérie; Chabalier, Jean-Bernard de; Lemarchand, Arnaud

doi:10.1007/1345_2020_101

Cited by 4 publications

(4 citation statements)

References 20 publications

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“…The islands of Guadeloupe and Martinique, for which station density is highest, show subsidence rates from 0 ± 0.3 to 3.8 ± 0.9 mm/yr (Fig. 2b), in good agreement with a recent study by Sakic et al (2020) who found similar vertical velocities from two independent geodetic solutions (Supporting Information Fig. S1 and Table S3).…”

Section: O B S E Rv E D V E Rt I C a L M O T I O N Ssupporting

confidence: 89%

“…Panels on the right show comparisons between different solutions (b-d) where the dashed line indicates the diagonal on which velocities would plot if they are equal in magnitude between solutions. The comparison with the two solutions of Sakic et al (2020) shows a good agreement with the one presented here, with subsidence at most common sites at rates that are consistent within uncertainties. Differences between our solution and those of Sakic et al (2020) likely stem from the duration of the time-series used (longer in our analysis), the fact that they use a PPP approach versus a network strategy, as well as a different implementation of the ITRF14 reference frame.…”

Section: Data Ava I L a B I L I T Ysupporting

confidence: 81%

“…A comparison with a previous analysis of vertical velocities limited to the island of Martinique and Guadeloupe (Sakic et al 2020). Velocities for all three solutions are shown per station, ordered by latitude with highest latitudes towards the top (a).…”

Section: Data Ava I L a B I L I T Ymentioning

confidence: 96%

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Ongoing tectonic subsidence in the Lesser Antilles subduction zone

Rijsingen

Calais

Jolivet

et al. 2022

Geophysical Journal International

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Summary 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.

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Section: O B S E Rv E D V E Rt I C a L M O T I O N Ssupporting

confidence: 89%

Section: Data Ava I L a B I L I T Ysupporting

confidence: 81%

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Ongoing tectonic subsidence in the Lesser Antilles subduction zone

Rijsingen

Calais

Jolivet

et al. 2022

Geophysical Journal International

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“…show a general pattern of subsidence of the Lesser Antilles, while islands at the edges of the subduction (i.e., the Virgin Islands in the North and Trinidad in the South) show uplift. The islands of Guadeloupe and Martinique, for which station density is highest, show subsidence rates between 0 ± 0.3 to 3.8 ± 0.9 mm/yr (Figure 2B), in good agreement with a recent study by Sakic et al (2020) who found similar vertical velocities from two independent geodetic solutions. The variability likely results from local site conditions, but mostly from variations in time series duration amongst GNSS stations.…”

Section: Vertical Gnss Confirms Uncoupled Subduction Interfacesupporting

confidence: 90%

Ongoing tectonic subsidence in the Lesser Antilles subduction zone

Rijsingen¹,

Calais²,

Jolivet³

et al. 2022

Preprint

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It has been proposed that interseismic coupling along the Lesser Antilles subduction interface could be responsible for subsidence observed over the past 125,000 to 100 years inferred from geological data on Quaternary coral terraces and active micro-atolls in the central part of the arc. However, horizontal GNSS velocities show that the Lesser Antilles subduction zone is currently experiencing low interseismic coupling, meaning that little to no elastic strain currently builds up as the North-and South American plates subduct beneath the Caribbean plate. Here we show, using modern geodetic data, a general subsidence of the Lesser Antilles island arc at 1-2 mm/yr over the past 20 years, in agreement with the ~100-year trend of 1.3 ± 1.1 mm/yr subsidence derived from coral micro-atolls in eastern Martinique. Using elastic dislocation models, we show that a locked, or partially locked subduction interface would produce uplift of the island arc, opposite to present-day and recent geological observations, hence supporting a poorly-coupled subduction. This subsidence since at least 125 ka is in line with the extensional tectonics observed along the arc since the mid-Miocene. The margin-wide subsidence is therefore likely controlled by large-scale geodynamic processes that operate over the long-term. Such processes could also play a role in tuning the aseismic character of the subduction megathrust, which appears to be a long-term feature.

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