georefid:2013-046517SEDIS Publication Catalogueana.macario@awi.dehttp://sedis.iodp.org/pub-catalogue/informationpointOfContact2013-07-08T00:00:00Zhttp://sedis.iodp.org/pub-catalogue/index.php?id=10.1029/2011GC003583<gco:CharacterString>In situ stress state from walkaround VSP anisotropy in the Kumano Basin southeast of the Kii Peninsula, Japan</gco:CharacterString>2011-01-01publicationgeorefid:2013-046517doi:10.1029/2011GC003583Tsuji, TakeshiKyoto University, Graduate School of Engineering, Kyoto, JapanauthorHino, RyotaTohoku University, JapanauthorSanada, YoshinoriJapan Agency for Marine-Earth Science and Technology, JapanauthorYamamoto, KiyohikoUniversity of Tokyo, JapanauthorPark, Jin-OhUniversity of Texas at Austin, United StatesauthorNo, TetsuoUniversity of California at Davis, United StatesauthorAraki, EiichiroUniversity of Hawaii at Manoa, United StatesauthorBangs, Nathanauthorvon Huene, RolandauthorMoore, Gregory F.authorKinoshita, MasatakaauthorAmerican Geophysical Union and The Geochemical Society, United StatespublisherdocumentDigitalGeochemistry, Geophysics, Geosystems - G (super 3)12To reveal the stress state within the Kumano basin, which overlies the Nankai accretionary prism, we estimated seismic anisotropy from walkaround vertical seismic profiling (VSP) data recorded at Site C0009 during Integrated Ocean Drilling Program (IODP) Expedition 319. We obtained the following anisotropic parameters: (1) P wave velocity anisotropy derived from azimuthal normal moveout (NMO) velocity analysis, (2) P wave amplitude variation with azimuth, and (3) axes of symmetry of S wave splitting. Azimuthal variations of P wave velocity by ellipsoidal fitting analysis showed that P wave velocity anisotropy within sediments of the Kumano basin was approximately 5%. Both the directions of fast P wave velocity and strong amplitude are aligned with the convergence vector of the Philippine Sea plate. Furthermore, S wave splitting analysis indicated that S wave polarization axes were parallel to and normal to the direction of plate subduction. These results indicate that the maximum horizontal stress at Site C0009 in the Kumano basin is in the direction of plate subduction. The horizontal differential stress estimated from the P wave velocity anisotropy (2.7 approximately 5.5 MPa) indicates that the maximum horizontal stress is similar in magnitude to (or a little higher than) the vertical stress.completedSolid-earth geophysicsApplied geophysicsactive faultsamplitudeanisotropybody wavescrustdownhole methodselastic wavesExpedition 319faultsgeophysical methodsgeophysical profilesgeophysical surveysIntegrated Ocean Drilling ProgramIODP Site C0009Kumano Basinmarine geologyNanTroSEIZENorth PacificNorthwest Pacificoceanic crustP-wavesPacific OceanPhilippine Sea Plateplate tectonicsS-wavesseismic methodsseismic profilesseismic wavesseismicitystresssubduction zonessurveystectonophysicsvelocityvertical seismic profilesWest Pacificurn:org.iodp:exp:319urnlargerWorkCitationcampaignurn:org.iodp:exp:319:site:C0009urnlargerWorkCitationstudyurn:org.iodp:exp:319urnlargerWorkCitationcampaignEnglishgeoscientificInformation135.3000137.300032.300034.3000application/pdfunknownSEDIS Publication Catalogueana.macario@awi.dehttp://sedis.iodp.org/pub-catalogue/informationpointOfContacthttp://onlinelibrary.wiley.com/journal/10.1002/(ISSN)1525-2027/homepage/G3_Special_Section_Proposal_Form.pdfdownload