Blog
About

11
views
0
recommends
+1 Recommend
1 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: found
      Is Open Access

      Data report: analysis of shear wave anisotropy in upper oceanic crust, ODP/IODP Hole 1256D: Expedition 335

      ,

      Proceedings of the IODP

      Integrated Ocean Drilling Program

      Read this article at

      ScienceOpenPublisher
      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          Integrated Ocean Drilling Program Hole 1256D is one of the few deep holes that penetrate through the upper oceanic crust and offers a unique chance to study its anisotropic properties as a function of depth. In this report, we present the results of anisotropy analysis using downhole sonic logging data acquired in Hole 1256D. The analysis is based on the detection of shear wave splitting in azimuthally anisotropic formations; however, poor borehole conditions, high levels of noise, and insufficient tool rotation presented significant challenges in this analysis. Anisotropy could be reliably evaluated only over a few select depth intervals, and they suggest very low shear wave anisotropy, within a range of 0%-1%. In particular, the deepest logged section within the sheeted dike interval is characterized by good borehole conditions and high coherence of shear wave fields, but shear wave velocity appears to be isotropic and/or characterized by weak anisotropy below the detection limit of the Dipole Sonic Imager used to acquire the data.

          Related collections

          Most cited references 23

          • Record: found
          • Abstract: not found
          • Article: not found

          Oceanic crustal thickness from seismic measurements and rare earth element inversions

            Bookmark
            • Record: found
            • Abstract: not found
            • Article: not found

            Seismic anisotropy and mantle deformation: What have we learned from shear wave splitting?

             M. K. Savage (1999)
              Bookmark
              • Record: found
              • Abstract: found
              • Article: not found

              Trench-parallel flow beneath the nazca plate from seismic anisotropy.

               R Russo,  P G Silver (1994)
              Shear-wave splitting of S and SKS phases reveals the anisotropy and strain field of the mantle beneath the subducting Nazca plate, Cocos plate, and the Caribbean region. These observations can be used to test models of mantle flow. Two-dimensional entrained mantle flow beneath the subducting Nazca slab is not consistent with the data. Rather, there is evidence for horizontal trench-parallel flow in the mantle beneath the Nazca plate along much of the Andean subduction zone. Trench-parallel flow is attributale utable to retrograde motion of the slab, the decoupling of the slab and underlying mantle, and a partial barrier to flow at depth, resulting in lateral mantle flow beneath the slab. Such flow facilitates the transfer of material from the shrinking mantle reservoir beneath the Pacific basin to the growing mantle reservoir beneath the Atlantic basin. Trenchparallel flow may explain the eastward motions of the Caribbean and Scotia sea plates, the anomalously shallow bathymetry of the eastern Nazca plate, the long-wavelength geoid high over western South America, and it may contribute to the high elevation and intense deformation of the central Andes.
                Bookmark

                Author and article information

                Journal
                10.2204/iodp.proc.335.2012
                Proceedings of the IODP
                Integrated Ocean Drilling Program
                1930-1014
                02 November 2015
                10.2204/iodp.proc.335.202.2015

                This work is licensed under a Creative Commons Attribution 4.0 Unported License. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/

                Product
                Self URI (journal page): http://publications.iodp.org/

                Comments

                Comment on this article