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:2122/6473 2023-05-15T14:01:36+02:00 Seismic Anisotropy Analysis in the Victoria Land Region (Antarctica) Salimbeni, Simone Pondrelli, Silvia Danesi, Stefania Morelli, Andrea Salimbeni, Simone; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia Pondrelli, Silvia; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia Danesi, Stefania; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia Morelli, Andrea; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia 2010-05 http://hdl.handle.net/2122/6473 en eng European Geoscience Union General Assembly http://hdl.handle.net/2122/6473 open Seismic Anisotropy Mantle processes Antarctica 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy Poster session 2010 ftingv 2022-07-29T06:05:47Z 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 NNWSSE 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 NESW direction over the entire region, but other anisotropy directions are present and find an interpretation when examined in the context of regional tectonics. Published Vienna 3.3. Geodinamica e struttura dell'interno della Terra open Other/Unknown Material 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 |
Seismic Anisotropy Mantle processes Antarctica 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy |
spellingShingle |
Seismic Anisotropy Mantle processes Antarctica 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy Salimbeni, Simone Pondrelli, Silvia Danesi, Stefania Morelli, Andrea Seismic Anisotropy Analysis in the Victoria Land Region (Antarctica) |
topic_facet |
Seismic Anisotropy Mantle processes Antarctica 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 NNWSSE 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 NESW direction over the entire region, but other anisotropy directions are present and find an interpretation when examined in the context of regional tectonics. Published Vienna 3.3. Geodinamica e struttura dell'interno della Terra open |
author2 |
Salimbeni, Simone; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia Pondrelli, Silvia; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia Danesi, Stefania; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia Morelli, Andrea; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia |
format |
Other/Unknown Material |
author |
Salimbeni, Simone Pondrelli, Silvia Danesi, Stefania Morelli, Andrea |
author_facet |
Salimbeni, Simone Pondrelli, Silvia Danesi, Stefania Morelli, Andrea |
author_sort |
Salimbeni, Simone |
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 |
2010 |
url |
http://hdl.handle.net/2122/6473 |
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 |
European Geoscience Union General Assembly http://hdl.handle.net/2122/6473 |
op_rights |
open |
_version_ |
1766271549223993344 |