Imaging the mantle flow field beneath the Atlantic Ocean using seismic waves

• Main Author: Wang, Danielle
• Format: Text
• Language: unknown
• Published: Scholars' Mine 2014
• Subjects: Mid-Atlantic Ridge; North Atlantic
• Online Access: https://scholarsmine.mst.edu/ugrc/2014/full-schedule/84

The mid-ocean ridge in the Atlantic Ocean, which is also called Mid-Atlantic Ridge (MAR), is a divergent tectonic plate boundary and part of the longest mountain range in the world. It separates the Eurasian Plate and North American Plate in the North Atlantic, and the African Plate from the South American Plate in the South Atlantic. MAR is caused by sea floor spreading and can also be an indication of plate motion. Studying the mechanism of plate motion in this area is meaningful for giving an idea of continental drift which is being discussed for a long time. We studied the mechanism of plate motion in the Atlantic Ocean by imaging the mantle flow field using seismic waves, which is called “shear wave splitting”(SWS). SWS is a robust tool to infer the direction and strength of seismic anisotropy in the lithosphere and underlying asthenosphere. Measurements of the splitting or birefringence of seismic shear waves that have passed through the Earth’s mantle yield constraints on the strength and geometry of elastic anisotropy in various regions. In turn, information about the occurrence and character of seismic anisotropy allows us to make inferences about the style and geometry of mantle flow because anisotropy is a direct consequence of deformational processes. Splitting of P-to-S converted phases at the core-mantle boundary (XKS, including SKS, PKS, and SKKS) is a direct manifestation of seismic anisotropy, which is mostly the result of deformational processes in the Earth’s lithosphere and asthenosphere. As demonstrated by hundreds of XKS splitting studies, spatial distribution of two splitting parameters (ɸ, which is the polarization direction of the fast shear wave, and δt which is the splitting delay time between the fast and slow shear waves) has played an essential role in the investigation of anisotropic structure and associated mantle dynamic processes of the Earth. We required and processed the broadband XKS data recorded in the Atlantic Ocean area at the Incorporated Research Institutions for ...