S-Local-Wave Seismic Anisotropy in the Forearc Above the Subducted Nazca Plate Between 33°S and 34.5°S
S-wave splitting from local earthquakes within the Nazca plate that are deeper than the interplate seismogenic zone enabled the determination of the fast velocity direction, Φ, and the lag time, δt, in the forearc of the overriding plate. Data were collected from 20 seismic stations, most of which w...
Guardado en:
| Publicado: |
2016
|
|---|---|
| Materias: | |
| Acceso en línea: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00334553_v173_n4_p1143_Nacif http://hdl.handle.net/20.500.12110/paper_00334553_v173_n4_p1143_Nacif |
| Aporte de: |
| id |
paper:paper_00334553_v173_n4_p1143_Nacif |
|---|---|
| record_format |
dspace |
| spelling |
paper:paper_00334553_v173_n4_p1143_Nacif2023-06-08T15:00:32Z S-Local-Wave Seismic Anisotropy in the Forearc Above the Subducted Nazca Plate Between 33°S and 34.5°S intraplate events Nazca plate Seismic anisotropy subduction zone Anisotropy Seismology Shear waves Dimensional variations intraplate events Nazca plate Quality evaluation Seismic anisotropy Seismogenic zones Subduction zones Velocity directions Tectonics forearc basin intraplate process Nazca plate S-wave seismic anisotropy subduction zone wave splitting S-wave splitting from local earthquakes within the Nazca plate that are deeper than the interplate seismogenic zone enabled the determination of the fast velocity direction, Φ, and the lag time, δt, in the forearc of the overriding plate. Data were collected from 20 seismic stations, most of which were temporary, deployed between ~33.5°S and ~34.5°S and included part of the normal subduction section to the south and part of the transitional section to flat subduction to the north. The fast velocity direction has a complex pattern with three predominant directions northwest–southeast, north–south and northeast–southwest and relatively high δt. A quality evaluation of the highest measurements enabled us to identify possible cycle skipping in some of the measurements, which could be responsible for the large observed lag time. We consider that most of the anisotropy that was observed in the forearc is probably located in the mantle wedge, and a minor part is located in the crust. The complex pattern of splitting parameters when the anisotropy is associated at the mantle wedge could be the result of three-dimensional variations in the subducting Nazca plate at these latitudes. Also, similarities between the splitting parameters and the principal compressional stress direction from Pliocene and Quaternary rocks suggest that the anisotropy in the crust could originate by tectonic local stress. © 2015, Springer Basel. 2016 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00334553_v173_n4_p1143_Nacif http://hdl.handle.net/20.500.12110/paper_00334553_v173_n4_p1143_Nacif |
| institution |
Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
| collection |
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
intraplate events Nazca plate Seismic anisotropy subduction zone Anisotropy Seismology Shear waves Dimensional variations intraplate events Nazca plate Quality evaluation Seismic anisotropy Seismogenic zones Subduction zones Velocity directions Tectonics forearc basin intraplate process Nazca plate S-wave seismic anisotropy subduction zone wave splitting |
| spellingShingle |
intraplate events Nazca plate Seismic anisotropy subduction zone Anisotropy Seismology Shear waves Dimensional variations intraplate events Nazca plate Quality evaluation Seismic anisotropy Seismogenic zones Subduction zones Velocity directions Tectonics forearc basin intraplate process Nazca plate S-wave seismic anisotropy subduction zone wave splitting S-Local-Wave Seismic Anisotropy in the Forearc Above the Subducted Nazca Plate Between 33°S and 34.5°S |
| topic_facet |
intraplate events Nazca plate Seismic anisotropy subduction zone Anisotropy Seismology Shear waves Dimensional variations intraplate events Nazca plate Quality evaluation Seismic anisotropy Seismogenic zones Subduction zones Velocity directions Tectonics forearc basin intraplate process Nazca plate S-wave seismic anisotropy subduction zone wave splitting |
| description |
S-wave splitting from local earthquakes within the Nazca plate that are deeper than the interplate seismogenic zone enabled the determination of the fast velocity direction, Φ, and the lag time, δt, in the forearc of the overriding plate. Data were collected from 20 seismic stations, most of which were temporary, deployed between ~33.5°S and ~34.5°S and included part of the normal subduction section to the south and part of the transitional section to flat subduction to the north. The fast velocity direction has a complex pattern with three predominant directions northwest–southeast, north–south and northeast–southwest and relatively high δt. A quality evaluation of the highest measurements enabled us to identify possible cycle skipping in some of the measurements, which could be responsible for the large observed lag time. We consider that most of the anisotropy that was observed in the forearc is probably located in the mantle wedge, and a minor part is located in the crust. The complex pattern of splitting parameters when the anisotropy is associated at the mantle wedge could be the result of three-dimensional variations in the subducting Nazca plate at these latitudes. Also, similarities between the splitting parameters and the principal compressional stress direction from Pliocene and Quaternary rocks suggest that the anisotropy in the crust could originate by tectonic local stress. © 2015, Springer Basel. |
| title |
S-Local-Wave Seismic Anisotropy in the Forearc Above the Subducted Nazca Plate Between 33°S and 34.5°S |
| title_short |
S-Local-Wave Seismic Anisotropy in the Forearc Above the Subducted Nazca Plate Between 33°S and 34.5°S |
| title_full |
S-Local-Wave Seismic Anisotropy in the Forearc Above the Subducted Nazca Plate Between 33°S and 34.5°S |
| title_fullStr |
S-Local-Wave Seismic Anisotropy in the Forearc Above the Subducted Nazca Plate Between 33°S and 34.5°S |
| title_full_unstemmed |
S-Local-Wave Seismic Anisotropy in the Forearc Above the Subducted Nazca Plate Between 33°S and 34.5°S |
| title_sort |
s-local-wave seismic anisotropy in the forearc above the subducted nazca plate between 33°s and 34.5°s |
| publishDate |
2016 |
| url |
https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00334553_v173_n4_p1143_Nacif http://hdl.handle.net/20.500.12110/paper_00334553_v173_n4_p1143_Nacif |
| _version_ |
1768542495976718336 |