Sea-bottom shear-wave velocities and mode conversions
Autor(a) principal: | |
---|---|
Data de Publicação: | 2005 |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Revista Brasileira de Geofísica (Online) |
Texto Completo: | http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0102-261X2005000100007 |
Resumo: | Elastic parameters for shallow marine sediments were obtained from the literature (Hamilton (1976,1979); Hovem et al. (1991); Esteves (1996)) and previously unpublished geotechnical data from offshore Brazil. The Brazilian data showed reasonable agreement with Hamilton's results except in the very shallow (above 10 m) sedimentary section. A second order equation to calculate VS as a function of depth in marine sediments is derived empirically down to a depth of 140 m. Analyses of transmission and reflection coefficients for compressional- and shear-wave energy mode conversion using Zoeppritz equations were performed for both the sea bottom and a typical hydrocarbon reservoir top of Tertiary age. It is concluded that most S-wave reflection data recorded on the ocean floor by OBC is related to upcoming energy converted at an interface at depth and not from a downgoing shear conversion at the ocean floor. It was also concluded that, using elastic assumptions, mode conversion (both P- to S- and S- to P-) of the up going energy is negligible in the shallow (above 160 m) sediments. |
id |
SBG-3_9af2f7bebdc46858c62e2daaf2e893bb |
---|---|
oai_identifier_str |
oai:scielo:S0102-261X2005000100007 |
network_acronym_str |
SBG-3 |
network_name_str |
Revista Brasileira de Geofísica (Online) |
repository_id_str |
|
spelling |
Sea-bottom shear-wave velocities and mode conversionsV S in marine sedimentsmode conversionElastic parameters for shallow marine sediments were obtained from the literature (Hamilton (1976,1979); Hovem et al. (1991); Esteves (1996)) and previously unpublished geotechnical data from offshore Brazil. The Brazilian data showed reasonable agreement with Hamilton's results except in the very shallow (above 10 m) sedimentary section. A second order equation to calculate VS as a function of depth in marine sediments is derived empirically down to a depth of 140 m. Analyses of transmission and reflection coefficients for compressional- and shear-wave energy mode conversion using Zoeppritz equations were performed for both the sea bottom and a typical hydrocarbon reservoir top of Tertiary age. It is concluded that most S-wave reflection data recorded on the ocean floor by OBC is related to upcoming energy converted at an interface at depth and not from a downgoing shear conversion at the ocean floor. It was also concluded that, using elastic assumptions, mode conversion (both P- to S- and S- to P-) of the up going energy is negligible in the shallow (above 160 m) sediments.Sociedade Brasileira de Geofísica2005-03-01info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersiontext/htmlhttp://old.scielo.br/scielo.php?script=sci_arttext&pid=S0102-261X2005000100007Revista Brasileira de Geofísica v.23 n.1 2005reponame:Revista Brasileira de Geofísica (Online)instname:Sociedade Brasileira de Geofísica (SBG)instacron:SBG10.1590/S0102-261X2005000100007info:eu-repo/semantics/openAccessRodriguez-Suarez,Carloseng2007-03-23T00:00:00Zoai:scielo:S0102-261X2005000100007Revistahttp://www.scielo.br/rbgONGhttps://old.scielo.br/oai/scielo-oai.php||sbgf@sbgf.org.br1809-45110102-261Xopendoar:2007-03-23T00:00Revista Brasileira de Geofísica (Online) - Sociedade Brasileira de Geofísica (SBG)false |
dc.title.none.fl_str_mv |
Sea-bottom shear-wave velocities and mode conversions |
title |
Sea-bottom shear-wave velocities and mode conversions |
spellingShingle |
Sea-bottom shear-wave velocities and mode conversions Rodriguez-Suarez,Carlos V S in marine sediments mode conversion |
title_short |
Sea-bottom shear-wave velocities and mode conversions |
title_full |
Sea-bottom shear-wave velocities and mode conversions |
title_fullStr |
Sea-bottom shear-wave velocities and mode conversions |
title_full_unstemmed |
Sea-bottom shear-wave velocities and mode conversions |
title_sort |
Sea-bottom shear-wave velocities and mode conversions |
author |
Rodriguez-Suarez,Carlos |
author_facet |
Rodriguez-Suarez,Carlos |
author_role |
author |
dc.contributor.author.fl_str_mv |
Rodriguez-Suarez,Carlos |
dc.subject.por.fl_str_mv |
V S in marine sediments mode conversion |
topic |
V S in marine sediments mode conversion |
description |
Elastic parameters for shallow marine sediments were obtained from the literature (Hamilton (1976,1979); Hovem et al. (1991); Esteves (1996)) and previously unpublished geotechnical data from offshore Brazil. The Brazilian data showed reasonable agreement with Hamilton's results except in the very shallow (above 10 m) sedimentary section. A second order equation to calculate VS as a function of depth in marine sediments is derived empirically down to a depth of 140 m. Analyses of transmission and reflection coefficients for compressional- and shear-wave energy mode conversion using Zoeppritz equations were performed for both the sea bottom and a typical hydrocarbon reservoir top of Tertiary age. It is concluded that most S-wave reflection data recorded on the ocean floor by OBC is related to upcoming energy converted at an interface at depth and not from a downgoing shear conversion at the ocean floor. It was also concluded that, using elastic assumptions, mode conversion (both P- to S- and S- to P-) of the up going energy is negligible in the shallow (above 160 m) sediments. |
publishDate |
2005 |
dc.date.none.fl_str_mv |
2005-03-01 |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/article |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
format |
article |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0102-261X2005000100007 |
url |
http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0102-261X2005000100007 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
10.1590/S0102-261X2005000100007 |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
text/html |
dc.publisher.none.fl_str_mv |
Sociedade Brasileira de Geofísica |
publisher.none.fl_str_mv |
Sociedade Brasileira de Geofísica |
dc.source.none.fl_str_mv |
Revista Brasileira de Geofísica v.23 n.1 2005 reponame:Revista Brasileira de Geofísica (Online) instname:Sociedade Brasileira de Geofísica (SBG) instacron:SBG |
instname_str |
Sociedade Brasileira de Geofísica (SBG) |
instacron_str |
SBG |
institution |
SBG |
reponame_str |
Revista Brasileira de Geofísica (Online) |
collection |
Revista Brasileira de Geofísica (Online) |
repository.name.fl_str_mv |
Revista Brasileira de Geofísica (Online) - Sociedade Brasileira de Geofísica (SBG) |
repository.mail.fl_str_mv |
||sbgf@sbgf.org.br |
_version_ |
1754820936382545920 |