Constraints on mantle flow at the Caribbean–South American plate boundary inferred from shear wave splitting

2009 ◽  
Vol 114 (B2) ◽  
Author(s):  
Mark A. Growdon ◽  
Gary L. Pavlis ◽  
Fenglin Niu ◽  
Frank L. Vernon ◽  
Herbert Rendon
Keyword(s):  
Shear Wave ◽  
Plate Boundary ◽  
Shear Wave Splitting ◽  
Mantle Flow ◽  
South American ◽  
South American Plate ◽  
Wave Splitting ◽  
The Caribbean

scholarly journals CRUSTAL SEISMIC ANISOTROPY AT THE EDGE OF THE SOUTH-EAST BORDER OF CARIBBEAN AND SOUTH AMERICAN PLATES

2013 ◽  
Vol 31 (4) ◽  
pp. 595
Author(s):  
Tomislav E. Monjak Espinoza ◽  
Laura Teresa Piñero Feliciangeli
Keyword(s):  
Shear Wave ◽  
Seismic Anisotropy ◽  
Shear Wave Splitting ◽  
Mantle Flow ◽  
Fast Wave ◽  
South American ◽  
The South ◽  
Large Variability ◽  
Wave Splitting ◽  
The Caribbean

ABSTRACT. Anisotropic properties in the NE of the Caribbean-South American plate are investigated based on the analysis of shear-wave splitting from new S local phase data. At the collisional front in the Caribbean and the South American plates and within the retro-arc region, fast wave polarization from local S phases show considerable variability. δt are small (<0.14 s) and no dependence with depth is observed suggesting the presence of an heterogeneous anisotropic region confined to the crust and that most of the upper-mantle wedge is isotropic. In the fore-arc, φ is fairly constant, the average value is sub-parallel to the Lesser Antilles trench and differs from teleseismic result, which is perpendicular to the trench, which suggests that the crust and mantle are decoupled. The difference between the δt found in S local events and teleseismic, suggests that there is another source of deep anisotropy, which can be attributed to mantle flow underneath or around the edges of the subducting Atlantic plate beneath the Caribbean. A mix combination of deformation mechanism such as micro-fractures EDA and vertical foliation on metamorphic rocks could be responsible for the large variability found for δt in S local phases in this region.Keywords: seismic anisotropy, deformation mechanisms, shear-wave splitting, crust, mantle RESUMEN. Se investigan las características anisotrópicas en el NE de la placa Caribe-Sur América basados en el análisis de nuevos resultados del desdoblamiento de ondas de corte en fases locales S. En el frente de colisión entre placa Caribe y Suramerica y en la zona de retro-arco, la polarización de onda rápida en eventos locales S muestran considerable variabilidad. Los δt son pequeños (<0,14s) y no presenta dependencia con la profundidad, sugiriendo la presencia de una región anisotropícamente heterogenea confinada a la corteza, siendo además la cuña del manto superior isotrópico. En el ante-arco, φ es poco variable, el valor promedio es sub-paralello a la trinchera de las Antillas Menores y difiere del valor obtenido para fases telesísmicas el cual es perpendicular a la trinchera, lo cual sugiere que la corteza y el manto en esta zona se encuentran desacoplados. La diferencia entre los δt en eventos locales S y telesísmicos, sugiere que existe otra fuente de anisotropía profunda, que se puede atribuir a flujo mantélico debajo o alrededor de los bordes de la placa Atlántica en subducción debajo del Caribe. Una combinación de mecanismos de deformación, tales como micro-fracturas EDA y foliación vertical en rocas metamórficas podría ser responsable de la gran variabilidad encontrada en los δt en fases S locales en esta región.Palabras claves: anisotropía sísmica, mecanismos de deformación, doblamiento de ondas de corte, corteza, manto.

scholarly journals Shear wave splitting and mantle flow beneath LA RISTRA

2003 ◽  
Vol 30 (12) ◽  
Author(s):  
Rengin Gök ◽  
James F. Ni ◽  
Michael West ◽  
Eric Sandvol ◽  
David Wilson ◽  
...  
Keyword(s):  
Shear Wave ◽  
Shear Wave Splitting ◽  
Mantle Flow ◽  
Wave Splitting

Seismic anisotropy and mantle flow constrained by shear wave splitting in central Myanmar

2021 ◽  
Author(s):  
Enbo Fan ◽  
Yumei He ◽  
Yinshuang Ai ◽  
Stephen S. Gao ◽  
Kelly H. Liu ◽  
...  
Keyword(s):  
Shear Wave ◽  
Seismic Anisotropy ◽  
Shear Wave Splitting ◽  
Mantle Flow ◽  
Wave Splitting

Crustal Deformation along the Caribbean — South American Plate Boundary Derived From The Casa GPS Project

1998 ◽  
pp. 417-422 ◽  
Author(s):  
Klaus Kaniuth ◽  
Hermann Drewes ◽  
Klaus Stuber ◽  
Herbert Tremel ◽  
Napoleón Hernández ◽  
...  
Keyword(s):  
Crustal Deformation ◽  
Plate Boundary ◽  
South American ◽  
South American Plate ◽  
The Caribbean

Mantle flow under the Central Alps: Constraints from non-vertical-ray SKS shear-wave splittting

2020 ◽  
Author(s):  
Eric Löberich ◽  
Götz Bokelmann
Keyword(s):  
Shear Wave ◽  
Upper Mantle ◽  
Seismic Anisotropy ◽  
Single Layer ◽  
Depth Resolution ◽  
Shear Wave Splitting ◽  
Mantle Flow ◽  
Central Alps ◽  
Upper Mantle Anisotropy ◽  
Wave Splitting

&lt;p&gt;The association of seismic anisotropy and deformation, as e.g. exploited by shear-wave splitting measurements, provides a unique opportunity to map the orientation of geodynamic processes in the upper mantle and to constraint their nature. However, due to the limited depth-resolution of steeply arriving core-phases, used for shear-wave splitting investigations, it appears difficult to differentiate between asthenospheric and lithospheric origins of observed seismic anisotropy. To change that, we take advantage of the different backazimuthal variations of fast orientation &lt;em&gt;&amp;#966;&lt;/em&gt; and delay time &lt;em&gt;&amp;#916;t&lt;/em&gt;, when considering the non-vertical incidence of phases passing through an olivine block with vertical b-axis as opposed to one with vertical c-axis. Both these alignments can occur depending on the type of deformation, e.g. a sub-horizontal foliation orientation in the case of a simple asthenospheric flow and a sub-vertical foliation when considering vertically-coherent deformation in the lithosphere. In this study we investigate the cause of seismic anisotropy in the Central Alps. Combining high-quality manual shear-wave splitting measurements of three datasets leads to a dense station coverage. Fast orientations &lt;em&gt;&amp;#966;&lt;/em&gt; show a spatially coherent and relatively simple mountain-chain-parallel pattern, likely related to a single-layer case of upper mantle anisotropy. Considering the measurements of the whole study area together, our non-vertical-ray shear-wave splitting procedure points towards a b-up olivine situation and thus favors an asthenospheric anisotropy source, with a horizontal flow plane of deformation. We also test the influence of position relative to the European slab, distinguishing a northern and southern subarea based on vertically-integrated travel times through a tomographic model. Differences in the statistical distribution of splitting parameters &lt;em&gt;&amp;#966;&lt;/em&gt; and &lt;em&gt;&amp;#916;t&lt;/em&gt;, and in the backazimuthal variation of &lt;em&gt;&amp;#948;&amp;#966;&lt;/em&gt; and &lt;em&gt;&amp;#948;&amp;#916;t&lt;/em&gt;, become apparent. While the observed seismic anisotropy in the northern subarea shows indications of asthenospheric flow, likely a depth-dependent plane Couette-Poiseuille flow around the Alps, the origin in the southern subarea remains more difficult to determine and may also contain effects from the slab itself.&lt;/p&gt;

scholarly journals Tectonic inversion in the Caribbean-South American plate boundary: GPS geodesy, seismology, and tectonics of theMw6.7 22 April 1997 Tobago earthquake

Tectonics ◽  
2015 ◽  
Vol 34 (6) ◽  
pp. 1181-1194 ◽  
Author(s):  
John C. Weber ◽  
Halldor Geirsson ◽  
Joan L. Latchman ◽  
Kenton Shaw ◽  
Peter La Femina ◽  
...  
Keyword(s):  
Plate Boundary ◽  
South American ◽  
South American Plate ◽  
Gps Geodesy ◽  
Tectonic Inversion ◽  
The Caribbean
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