SEISMIC ANISOTROPY ASSOCIATED WITH THE GREAT METEOR HOTSPOT TRACK: CONSTRAINTS FROM SHEAR-WAVE SPLITTING MEASUREMENTS

We have analyzed 738 pairs of well-defined shear wave splitting measurements recorded by 135 broadband seismic stations in the Eastern North American to study seismic anisotropy associated with the Great Meteor hotspot track. The broadband seismic data from the USArray and permanent stations were requested from the Incorporated Research Institutions for Seismology Data Management Center. The splitting parameters, fast polarization orientation and splitting time, are obtained by using the transverse component minimization method. The shear wave splitting measurements are manually checked to ensure quality. Our results indicate that the fast polarization orientation and splitting time are strongly related to the Great Meteor hotspot track and the abundant of mountain belts in the study area. We propose that the mantle flow orientation is driven by the southwestward movement of the bottom of the continental lithosphere, which gradually deepens toward the interior of the Eastern North American continent. Such movement deflects mantle flow and leads to E-W oriented fast orientations observed along the western and Eastern edges of the North American continent. Our observed result suggests that the Great Meteor hotspot track may construct a channel for plastic flow in the Earth’s asthenosphere. The asthenosphere flow may be deflected by the lithospheric channel which may cause the mantle flow orientation partial changed from E-W to NW-SE.