georefid:2011-101844SEDIS Publication Catalogueana.macario@awi.dehttp://sedis.iodp.org/pub-catalogue/informationpointOfContact2013-07-08T00:00:00Zhttp://sedis.iodp.org/pub-catalogue/index.php?id=10.1029/2010GC003261<gco:CharacterString>In situ stress state in the Nankai accretionary wedge estimated from borehole wall failures</gco:CharacterString>2010-01-01publicationgeorefid:2011-101844doi:10.1029/2010GC003261Chang, ChandongChungnam National University, Department of Geology, Daejeon, South KoreaauthorMcNeill, Lisa C.University of Southampton, United KingdomauthorMoore, J. CaseyUniversity of California at Santa Cruz, United StatesauthorLin, WeirenKochi Institute for Core Sample Research, JapanauthorConin, MarianneUniversite Aix Marseille III, FranceauthorYamada, YasuhiroKyoto University, JapanauthorAmerican Geophysical Union and The Geochemical Society, United StatespublisherdocumentDigitalGeochemistry, Geophysics, Geosystems - G (super 3)11We constrain the orientations and magnitudes of in situ stress tensors using borehole wall failures (borehole breakouts and drilling-induced tensile fractures) detected in four vertical boreholes (C0002, C0001, C0004, and C0006 from NW to SE) drilled in the Nankai accretionary wedge. The directions of the maximum horizontal principal stress (S (sub Hmax) ), indicated by the azimuths of borehole wall failures, are consistent in individual holes, but those in C0002 (margin-parallel S (sub Hmax) ) are nearly perpendicular to those in all other holes (margin-normal S (sub Hmax) ). Constrained stress magnitudes in C0001 and C0002, using logged breakout widths combined with empirical rock strength derived from sonic velocity, as well as the presence of the drilling-induced tensile fractures, suggest that the stress state in the shallow portion of the wedge (fore-arc basin and slope sediment formations) is predominantly in favor of normal faulting and that the stress state in the deeper accretionary prism is in favor of probable strike-slip faulting or possible reverse faulting. Thus, the stress regime appears to be divided with depth by the major geological boundaries such as unconformities or thrust faults. The margin-perpendicular tectonic stress components in the two adjacent sites, C0001 and C0002, are different, suggesting that tectonic force driven by the plate pushing of the Philippine Sea plate does not uniformly propagate. Rather, the stress field is inferred to be influenced by additional factors such as local deformation caused by gravitation-driven extension in the fore arc and thrusting and bending within individual geologic domains.completedStructural geologyaccretionary wedgesboreholescompressive strengthcrustdrillingequationsfailuresfaultsfracturesIntegrated Ocean Drilling ProgramIODP Site C0001IODP Site C0002IODP Site C0004IODP Site C0006lithosphereNankai TroughNanTroSEIZEnormal faultsNorth PacificNorthwest Pacificnumerical analysisoceanic crustoceanic lithospherePacific Oceanplate tectonicsstressstrike-slip faultssubductiontectonophysicstensile strengthWest Pacificurn:org.iodp:exp:314:site:C0001urnlargerWorkCitationstudyurn:org.iodp:exp:314urnlargerWorkCitationcampaignurn:org.iodp:exp:315:site:C0001urnlargerWorkCitationstudyurn:org.iodp:exp:315urnlargerWorkCitationcampaignurn:org.iodp:exp:314:site:C0002urnlargerWorkCitationstudyurn:org.iodp:exp:314urnlargerWorkCitationcampaignurn:org.iodp:exp:315:site:C0002urnlargerWorkCitationstudyurn:org.iodp:exp:315urnlargerWorkCitationcampaignurn:org.iodp:exp:326:site:C0002urnlargerWorkCitationstudyurn:org.iodp:exp:326urnlargerWorkCitationcampaignurn:org.iodp:exp:332:site:C0002urnlargerWorkCitationstudyurn:org.iodp:exp:332urnlargerWorkCitationcampaignurn:org.iodp:exp:338:site:C0002urnlargerWorkCitationstudyurn:org.iodp:exp:338urnlargerWorkCitationcampaignurn:org.iodp:exp:314:site:C0004urnlargerWorkCitationstudyurn:org.iodp:exp:314urnlargerWorkCitationcampaignurn:org.iodp:exp:316:site:C0004urnlargerWorkCitationstudyurn:org.iodp:exp:316urnlargerWorkCitationcampaignurn:org.iodp:exp:314:site:C0006urnlargerWorkCitationstudyurn:org.iodp:exp:314urnlargerWorkCitationcampaignurn:org.iodp:exp:316:site:C0006urnlargerWorkCitationstudyurn:org.iodp:exp:316urnlargerWorkCitationcampaignEnglishgeoscientificInformation136.1200136.360032.540033.1800application/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