Shear-Wave Splitting and Implications for Mantle Flow Beneath the MELT Region of the East Pacific Rise

• DOI: 10.1126/science.280.5367.1230
• Publication Date: 2002-07-27T09:43:20Z
• Authors: Cecily J. Wolfe; Sean C. Solomon
• Keywords: Shear wave splitting; Seismometer; Pacific Plate; Shear waves

Shear-wave splitting across the fast-spreading East Pacific Rise has been measured from records of SKS and SKKS phases on ocean-bottom seismometers Mantle Electromagnetic Tomography (MELT) Experiment. The direction fast shear-wave polarization is aligned parallel to spreading direction. Delay times between slow shear waves are asymmetric rise, off-axis values Plate twice those Nazca Plate. Splitting may reflect anisotropy associated with spreading-induced flow above a depth about 100 km, as well deeper contribution warm asthenospheric return Superswell region.