Character of the Caribbean–Gônave–North America plate boundaries in the upper mantle based on shear‐wave splitting

Benford, B.; Tikoff, Basil; DeMets, Charles

doi:10.1029/2012gl053766

Cited by 5 publications

(16 citation statements)

References 31 publications

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“…The splitting results are independent of the filter boundaries, both in angle and delay time. General trench-parallel orientation has been observed in previous studies (Russo et al, 1996;Piñero Feliciangeli & Kendall, 2008;Benford et al, 2012;Lynner and Long, 2013;Hodges & Miller, 2015). For many stations our results agree with previous results.…”

Section: Teleseismic Sks-splitting Resultssupporting

confidence: 74%

“…However, both studies find orientations at the northern stations (AGPR, AOPR, MPR) that divert from trench-parallel alignment in a rotation towards our results.East of Puerto Rico at station STVI the stacked result shows a trench-parallel orientation. This agrees with andHodges & Miller (2015) but is nearly orthogonal to the orientation seen byBenford et al (2012).…”

supporting

confidence: 91%

“…proportional to the magnitude of the splitting (δt) and the orientation represents the angle (φ). Previous results were obtained by Russo et al (1996), Benford et al (2012), and Hodges & Miller (2015). Details can be…”

Section: Discussionmentioning

confidence: 63%

“…This is in good agreement with results of . At station SDD, located in the centre of the Hispaniola microplate, Benford et al (2012) state that the number of observations of "Good and Fair splitting" results is low compared to other stations used in that study. They attribute the lack of measurements to the absence of anisotropy in this region as a result of locally undeformed mantle.…”

Section: Hispaniolamentioning

confidence: 57%

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Gaps, tears and seismic anisotropy around the subducting slabs of the Antilles

et al. 2017

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Seismic anisotropy in and beneath the subducting slabs of the Antilles is investigated using observations of shear-wave splitting. We use a combination of teleseismic and local events recorded at three-component broadband seismic stations on every major island in the area to map anisotropy in the crust, the mantle wedge and the slab/sub-slab mantle. To date this is the most comprehensive study of anisotropy in this region, involving 52 stations from 8 seismic networks. Local event delay times (0.21±0.12s) do not increase with depth, indicating a crustal origin in anisotropy and an isotropic mantle wedge. Teleseismic delay times are much larger (1.34±0.47s), with fast shear-wave polarisations that are predominantly parallel to trend of the arc. These observations can be interpreted three ways: (1) the presence of pre-existing anisotropy in the subducting slab; (2) anisotropy due to sub-slab mantle flow around the eastern margin of the nearly stationary Caribbean plate; (3) some combination of both mechanisms. However, there are two notable variations in the trench-parallel pattern of anisotropy-trench-perpendicular alignment is observed in narrow regions east of Puerto Rico and south of Martinique. These observations support previously proposed ideas of eastward sublithospheric mantle flow through gaps in the slab. Furthermore, the pattern of anisotropy south of Martinique, near Saint Lucia is consistent with a previously proposed location for the boundary between the North and South American plates.

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Section: Teleseismic Sks-splitting Resultssupporting

confidence: 74%

supporting

confidence: 91%

Section: Discussionmentioning

confidence: 63%

Section: Hispaniolamentioning

confidence: 57%

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Gaps, tears and seismic anisotropy around the subducting slabs of the Antilles

et al. 2017

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“…Present-day shortening between the Massif de la Selle and the Cul-de-Sac plain is partitioned over the EPGFZ and the thrust faults bordering the Cul-de-Sac plain in the south. The EPGFZ is presently active (Mann et al, 1983(Mann et al, , 1995Prentice et al, 2010) and rooted in the upper mantle (Benford et al, 2012b).…”

Section: Late Miocene -Present-day; Strike-slip To Transpressive Defomentioning

confidence: 99%

Polyphase tectonic history of the Southern Peninsula, Haiti: from folding-and-thrusting to transpressive strike-slip

et al. 2019

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The Southern Peninsula of Haiti is a seismically active east-west trending transpressive mountain range with elevations over 2 km. Present-day deformation is mainly partitioned along the left-lateral Enriquillo-Plantain Garden Fault Zone (EPGFZ) and associated oblique reverse faults and/or folds. The configuration of these faults, their respective timing, and the role of structural heritage on their development is poorly understood. To address these questions we present the results of extensive field campaigns, combined with satellite imagery interpretation and published data, which allows us to constrain the Cenozoic evolution of the Southern Peninsula. Our results show a polyphase tectonic history consisting of three major tectonic events: 1) Maastrichtian to early Paleocene crustal-scale folding that developed coevally with predominantly north to northeast dipping thrusts, resulting in uplift and erosion of the Cretaceous sedimentary cover in large parts of the Southern Peninsula. 2) Early Miocene uplift and erosion, which was strongest in the southwestern part of the peninsula and decreased eastwards, did not affect the Massif de la Selle. Uplift is most likely unrelated to strike-slip activity but resulted from folding in response to NE-SW shortening that possibly reactivated older, predominantly N-to NE-dipping thrusts. 3) Late Miocene to present-day deformation and uplift. Spatially distributed strike-slip started during the late Miocene and became progressively focused along the EPGFZ in the latest Miocene. Oblique and thrust faults locally postdate strike-slip activity from the Pliocene onward. Increase in compressional deformation from west to east is reflected by a change in structural style, with predominantly strike-slip faults in the west and transpressional faults in the east, the latter possibly rooted on the EPGFZ at depth. Paleo-stresses associated with a strikeslip regime are at a significantly high angle to the trace of the EPGFZ, indicating that the EPGFZ is a mechanically weak fault.

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Spatial Variations in Crustal and Mantle Anisotropy Across the North American‐Caribbean Boundary on Haiti

et al. 2020

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Haiti, on the island of Hispaniola, is situated across the North American-Caribbean plate boundary at the transition point between oblique subduction in the east and a transform plate boundary in the west. Here we use shear wave splitting measurements from S waves of local (0-50 km) and intermediate depth (50-150 km) earthquakes as well as SK(K)S phases from teleseismic earthquakes to ascertain good spatial and vertical resolution of the azimuthal anisotropic structure. This allows us to place new constraints on the pattern of deformation in the crust and mantle beneath this transitional region. SK(K)S results are dominated by plate boundary parallel (E-W) fast directions with~1.9 s delay times, indicating subslab trench parallel mantle flow is continuing westward along the plate boundary. Intermediate depth earthquakes originating within the subducting North American plate show a mean fast polarization direction of 065°and delay time of 0.46 s, subparallel to the relative plate motion between the Caribbean and North American plates (070°). We suggest a basal shear zone within the lower ductile crust and upper lithospheric mantle as being a potential major source of anisotropy above the subducting slab. Upper crustal anisotropy is isolated using shear wave splitting measurements on local seismicity, which show consistent delay times on the order of 0.2 s. The fast polarization directions indicate that the crustal anisotropy is controlled by the fault networks in close proximity to the major strike-slip faults, which bisect the north and south of Haiti, and by the regional stress field where faulting is less pervasive.

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Character of the Caribbean–Gônave–North America plate boundaries in the upper mantle based on shear‐wave splitting

Cited by 5 publications

References 31 publications

Gaps, tears and seismic anisotropy around the subducting slabs of the Antilles

Gaps, tears and seismic anisotropy around the subducting slabs of the Antilles

Polyphase tectonic history of the Southern Peninsula, Haiti: from folding-and-thrusting to transpressive strike-slip

Spatial Variations in Crustal and Mantle Anisotropy Across the North American‐Caribbean Boundary on Haiti

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