What is the cause for the slow velocities? Is this region lithosphere or asthenosphere?
As noted in the discussion above, the slow velocities could represent a chemical or fabric difference between the old Jurassic lithosphere and newer post-plume lithosphere, or it could represent hot asthenosphere at unusually shallow depths. We will seek to discriminate between these alternatives using measurements of seismic anisotropy (which is sensitive to fabric) and seismic attenuation (which is sensitive to temperature). We will use both SKS splitting and quasi-Love phases to quantify the anisotropy. SKS splitting provides an estimate of the vertically-integrated amount of anisotropy, and thus might be particularly good at quantifying the degree to which the “background” spreading-parallel fabric of the original Jurassic-age lithosphere has been disturbed. Quasi-Love phases are particularly useful in detecting the lateral boundary between two fabrics, and thus may be helpful in mapping out the extent of any disturbed region. SKS splitting has successfully been employed in an ocea
