PI: Kelly Liu
01/2008 - 12/2010 by National Science Foundation; EAR #: 0739015
My students and I are measuring shear-wave splitting parameters at all the broadband stations using a robust procedure that they developed to reliably measure and subjectively rank shear-wave splitting measurements. About 10,000 well-defined station-event pairs are being obtained as a result of the project. The first goal of the proposed study is to generate a database of individual (not station averaged) splitting parameters by using datasets accessible from the IRIS DMC. The second component is to use the comprehensive coherent database of splitting parameters to test the hypothesis of Marone and Romanowicz [2007], who, by joint inversion of surface waveforms and shear-wave splitting observations, suggested a pervasive two-layer anisotropic model beneath central and eastern North America.
Expected results from the proposed work will be used by a broad spectrum of geoscientists to address a wide range of fundamental questions regarding the structure and dynamics of the Earth’s deep interior. For instance, if the hypothesis of pervasive two-layer anisotropy passed the test using the coherent shear-wave splitting database to be produced by the proposed study, geodynamic modelers will deploy the two-layer model in their calculations, and mineral-physicists will perform experiments to study phase change and effects of water under the assumption that the lithosphere and the asthenosphere are decoupled.