Seismic Anisotropy Analysis in the Victoria Land Region (Antarctica)
We present shear-wave splitting results obtained from analysis of core refracted teleseismic phases recorded by permanent and temporary seismographic stations located in the Victoria Land region (Antarctica). We used eigenvalue technique to linearize the rotated and shifted shear-wave particle motio...
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ftingv:oai:www.earth-prints.org:2122/5492 2023-05-15T14:01:36+02:00 Seismic Anisotropy Analysis in the Victoria Land Region (Antarctica) Salimbeni, S. Pondrelli, S. Danesi, S. Morelli, A. Salimbeni, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia Pondrelli, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia Danesi, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia Morelli, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia 2009 http://hdl.handle.net/2122/5492 en eng Geophysical Journal International http://hdl.handle.net/2122/5492 open Antarctica Shear-wave splitting Seismic Anisotropy Mantle processes 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy manuscript 2009 ftingv 2022-07-29T06:05:26Z We present shear-wave splitting results obtained from analysis of core refracted teleseismic phases recorded by permanent and temporary seismographic stations located in the Victoria Land region (Antarctica). We used eigenvalue technique to linearize the rotated and shifted shear-wave particle motion, in order to determine the best splitting parameters. A well-scattered distribution of single shear-wave measurements has been obtained. Average values show clearly that dominant fast axis direction is NE-SW oriented, accordingly with previous measurements obtained around this zone. Only two stations, OHG and STAR show different orientations, with N-S and NNW-SSE main directions. On the basis of the periodicity of single shear-wave splitting measurements with respect to back-azimuths of events under study, we inferred the presence of lateral and vertical changes in the deep anisotropy direction. To test this hypothesis we have modelling waveforms using a cross-convolution technique in one and two anisotropic layer's cases. We obtained a significant improvement on the misfit in the double layer case for the cited couple of stations. For stations where a multi-layer structure does not fit, we looked for evidences of lateral anisotropy changes at depth through Fresnel zone computation. As expected, we find that anisotropy beneath the Transantarctic Mountains (TAM) is considerably different from that beneath the Ross Sea. This feature influences the measurement distribution for the two permanent stations TNV and VNDA. Our results show a dominant NE-SW direction over the entire region, but other anisotropy directions are present and find an interpretation when examined in the context of regional tectonics. Submitted 3.3. Geodinamica e struttura dell'interno della Terra JCR Journal open Manuscript Antarc* Antarctica Ross Sea Victoria Land Earth-Prints (Istituto Nazionale di Geofisica e Vulcanologia) Ross Sea Transantarctic Mountains Victoria Land |
institution |
Open Polar |
collection |
Earth-Prints (Istituto Nazionale di Geofisica e Vulcanologia) |
op_collection_id |
ftingv |
language |
English |
topic |
Antarctica Shear-wave splitting Seismic Anisotropy Mantle processes 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy |
spellingShingle |
Antarctica Shear-wave splitting Seismic Anisotropy Mantle processes 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy Salimbeni, S. Pondrelli, S. Danesi, S. Morelli, A. Seismic Anisotropy Analysis in the Victoria Land Region (Antarctica) |
topic_facet |
Antarctica Shear-wave splitting Seismic Anisotropy Mantle processes 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy |
description |
We present shear-wave splitting results obtained from analysis of core refracted teleseismic phases recorded by permanent and temporary seismographic stations located in the Victoria Land region (Antarctica). We used eigenvalue technique to linearize the rotated and shifted shear-wave particle motion, in order to determine the best splitting parameters. A well-scattered distribution of single shear-wave measurements has been obtained. Average values show clearly that dominant fast axis direction is NE-SW oriented, accordingly with previous measurements obtained around this zone. Only two stations, OHG and STAR show different orientations, with N-S and NNW-SSE main directions. On the basis of the periodicity of single shear-wave splitting measurements with respect to back-azimuths of events under study, we inferred the presence of lateral and vertical changes in the deep anisotropy direction. To test this hypothesis we have modelling waveforms using a cross-convolution technique in one and two anisotropic layer's cases. We obtained a significant improvement on the misfit in the double layer case for the cited couple of stations. For stations where a multi-layer structure does not fit, we looked for evidences of lateral anisotropy changes at depth through Fresnel zone computation. As expected, we find that anisotropy beneath the Transantarctic Mountains (TAM) is considerably different from that beneath the Ross Sea. This feature influences the measurement distribution for the two permanent stations TNV and VNDA. Our results show a dominant NE-SW direction over the entire region, but other anisotropy directions are present and find an interpretation when examined in the context of regional tectonics. Submitted 3.3. Geodinamica e struttura dell'interno della Terra JCR Journal open |
author2 |
Salimbeni, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia Pondrelli, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia Danesi, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia Morelli, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia |
format |
Manuscript |
author |
Salimbeni, S. Pondrelli, S. Danesi, S. Morelli, A. |
author_facet |
Salimbeni, S. Pondrelli, S. Danesi, S. Morelli, A. |
author_sort |
Salimbeni, S. |
title |
Seismic Anisotropy Analysis in the Victoria Land Region (Antarctica) |
title_short |
Seismic Anisotropy Analysis in the Victoria Land Region (Antarctica) |
title_full |
Seismic Anisotropy Analysis in the Victoria Land Region (Antarctica) |
title_fullStr |
Seismic Anisotropy Analysis in the Victoria Land Region (Antarctica) |
title_full_unstemmed |
Seismic Anisotropy Analysis in the Victoria Land Region (Antarctica) |
title_sort |
seismic anisotropy analysis in the victoria land region (antarctica) |
publishDate |
2009 |
url |
http://hdl.handle.net/2122/5492 |
geographic |
Ross Sea Transantarctic Mountains Victoria Land |
geographic_facet |
Ross Sea Transantarctic Mountains Victoria Land |
genre |
Antarc* Antarctica Ross Sea Victoria Land |
genre_facet |
Antarc* Antarctica Ross Sea Victoria Land |
op_relation |
Geophysical Journal International http://hdl.handle.net/2122/5492 |
op_rights |
open |
_version_ |
1766271542715482112 |