scholarly journals Automatic picking and probabilistic location for earthquake assessment in the Lesser Antilles subduction zone (1972–2012)

2021 ◽  
Vol 353 (S1) ◽  
pp. 1-23
Author(s):  
Frédérick Massin ◽  
Valérie Clouard ◽  
Inessa Vorobieva ◽  
François Beauducel ◽  
Jean-Marie Saurel ◽  
...  
Keyword(s):  
Subduction Zone ◽  
Lesser Antilles ◽  
Automatic Picking ◽  
Probabilistic Location ◽  
Earthquake Assessment

scholarly journals Caribbean plate boundaries control on the tectonic duality in the back-arc of the Lesser Antilles subduction zone during the Eocene

2021 ◽  
Author(s):  
Nestor Cerpa ◽  
Riad Hassani ◽  
Diane Arcay ◽  
Serge Lallemand ◽  
Clément Garrocq ◽  
...  
Keyword(s):  
Subduction Zone ◽  
Lesser Antilles ◽  
Plate Boundaries ◽  
Caribbean Plate ◽  
Back Arc

Lesser Antilles Subduction Zone in the Vicinity of Barbados

1973 ◽  
Vol 244 (138) ◽  
pp. 118-120 ◽  
Author(s):  
G. K. WESTBROOK ◽  
M. H. P. BOTT ◽  
J. H. PEACOCK
Keyword(s):  
Subduction Zone ◽  
Lesser Antilles

scholarly journals Deep structure of an island arc backstop, Lesser Antilles subduction zone

2003 ◽  
Vol 108 (B7) ◽  
Author(s):  
Gail L. Christeson ◽  
Nathan L. Bangs ◽  
Thomas H. Shipley
Keyword(s):  
Subduction Zone ◽  
Deep Structure ◽  
Island Arc ◽  
Lesser Antilles

scholarly journals Imaging the megathrust in subduction zones: lessons from Greece, Ecuador and the Lesser Antilles

2020 ◽  
Author(s):  
Mireille Laigle ◽  
Hans Agurto-Detzel ◽  
Anne Bécel ◽  
Milton Boucard ◽  
Caroline Chalumeau ◽  
...  
Keyword(s):  
Subduction Zone ◽  
Subduction Zones ◽  
Convergence Rates ◽  
Complex Structure ◽  
Receiver Functions ◽  
Lesser Antilles ◽  
Damage Effect ◽  
Physical Parameters ◽  
Strain Partitioning ◽  
The Impact

<p>Understanding the physical parameters and processes that control the seismogenic behavior of subduction zones megathrust faults remains one of the outstanding challenges in Earth Sciences.</p><p>Here we present important results from several large seismic experiments aimed at addressing this question. These experiments focused on the three subduction zones off Greece, the Lesser Antilles islands, and Ecuador, with different convergence rates and seismic activities. Surveys included multibeam bathymetry, multichannel reflection seismic (MCS) and wide-angle seismic (WAS) acquisitions over the forearc domain, as well as teleseismic receiver-functions and local earthquakes monitoring with temporary deployments of seismological networks.</p><p>Our results demonstrate the needs of both dense and extensive geophysical investigations.</p><p>In the central Lesser Antilles subduction zone, the interplate has been imaged down to the backstop at 12-15 km depth over the 350-km-long Antigua to Martinique islands segment. The outer forearc crust is strongly faulted in response to the two subducting Tiburon and Barracuda ridges (SISMANTILLES1-and-2 surveys). Two WAS profiles constrained the deeper geometry of the interplate down to the forearc Moho located at 28 km depth (TRAIL survey). The OBS networks deployed over several months (OBSANTILLES and OBSISMER surveys) revealed mantle wedge supraslab earthquakes and M4-5 possible repeaters with flat-trust mechanisms. The joint active-source/local earthquake seismic tomography let us to unveil the Vp and Vp/Vs heterogeneity along the slab surface and derive unprecedented constraints on multi-stage fluid release from subducting slow-spread oceanic lithosphere. Farther northwest, where the convergence obliquity strongly increases, we constrained the geometry of the interplate down to the forearc Moho at 25 km depth. Strain partitioning localizes on inherited major structures within the forearc domain, like the left-lateral partitioning system of the Anegada Passage and the 850-km-long Bunce fault, located along the backstop (ANTITHESIS survey).</p><p>On the southwestern Hellenic subduction zone, MCS and WAS acquisitions highlight the existence of an outer forearc crust beneath the forearc Matapan Trough, but its highly complex structure prevented us to image the interplate (ULYSSE survey). Acquisition by the R/V Marcus Langseth with its 8-km-long streamer finally made it possible (SISMED survey). Dense receiver-function acquisition on a 300-km-long mobile seismic network constrained the 3D geometry of the slab top underneath central Greece. This imaging revealed that the subducting oceanic crust and backstop updip limit are segmented by 9 trench-normal subvertical faults, seismically active at intermediate depths and possibly of inherited origin (THALES WAS RIGHT survey).</p><p>South of the 1906 M8.8 Ecuador-Columbia rupture area, the April 2016 Mw7.8 Pedernales subduction earthquake and its ensuing postseismic phase revealed a combination of seismic/aseismic slip behavior. Fluid-enriched parts of the megathrust fault and structural margin segmentation are hypothesized to play a major role in controlling slip behavior but direct observations are still lacking. Previous MCS acquisitions revealed very locally a fluid-rich subduction channel along with severe damage effect of the forearc margin due to seamounts subduction (SISTEUR survey). Forthcoming 3D seismic acquisition along this segment will examine the impact of the along-strike and along-dip variations of the physical properties and fluid content on the slip mode (HIPER survey).</p>

Seismogenic behaviour in the Lesser Antilles: Insights from geodetic observations

2020 ◽  
Author(s):  
Elenora van Rijsingen ◽  
Eric Calais ◽  
Romain Jolivet ◽  
Jean-Bernard de Chabalier ◽  
Jorge Jara ◽  
...  
Keyword(s):  
Subduction Zone ◽  
Temporal Distribution ◽  
Historical Earthquakes ◽  
Lesser Antilles ◽  
Model Parameters ◽  
Megathrust Earthquakes ◽  
Interseismic Coupling ◽  
Actual Degree ◽  
Block Models ◽  
Gps Time Series

<p>The Lesser Antilles subduction zone is a challenging region when it comes to unravelling its seismogenic behaviour. Over the last century, it has been seismically quiet, with no large thrust events recorded, leading to the question whether this subduction zone is able to produce large interplate earthquakes or not. The slow subduction velocity of ~20 mm/yr complicates this even further, as mega-earthquake recurrence times would be up to many hundreds of years in the case of a fully locked subduction interface, and up to several thousands of years for a partially locked interface. The record of two large historical earthquakes, a M ~8 in 1839 and M ~8.5 in 1843, is often referred to as evidence supporting the seismic character of the Lesser Antilles subduction zone. It remains, however, questionable whether these events actually occurred along the subduction interface.</p><p>Here we use GPS data acquired on various islands within the Antilles to infer interseismic coupling along the Lesser Antilles Arc. Previous block models have suggested low coupling of the subduction interface, making the occurrence of large megathrust earthquakes less likely. However, the non-uniqueness of these inversions, as well as uncertainties related to the distance between GPS stations and the subduction trench, cast doubts on how well the inferred coupling represents the actual degree of locking along the subduction interface. In this study, we attempt to improve these estimates, by using a Bayesian approach to derive a meaningful set of uncertainties on the distribution of interseismic coupling. By exploring the entire range of model parameters, we are able to provide a probabilistic estimate of interseismic coupling. To further improve our analysis with respect to previous models, we incorporate a layered elastic structure, as well as a more realistic fault geometry, testing two different slab models.</p><p>Our results suggest that the subduction interface of the Lesser Antilles subduction zone is most likely to be uncoupled. A sensitivity analysis highlights the deeper part of the interface (i.e., 30-60 km depth) as the region with higher sensitivity, since the GPS stations are distributed mostly above that portion of the subduction. A test regarding the proposed 1843 rupture contour reveals that this area is very unlikely to be locked. This apparent aseismic character of the Lesser Antilles raises questions about the role of slow slip along the interface. We therefore also analyse GPS time series to assess the spatial and temporal distribution of transient deformation signals in the region.</p>

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