资源环境科技发展态势分析平台

The morphologies of subducted remnants in the lower mantle are essential to our understanding of the history of plate tectonism. Here we image a high-velocity slab-like (HVSL) anomaly beneath the southeastern U.S. using waveforms from five deep earthquakes beneath South America recorded by the USArray. In addition to travel time anomalies, the multipathing of S and ScS phases at different distances are used to constrain the HVSL model. We jointly invert S and ScS traveltimes, amplitudes, and waveform complexities to produce a best fitting block model characterized by a rectangular shape with a 2.5% S wave velocity increase and tapered edges. While the Farallon slab is expected to dip primarily eastward, the HVSL structure apparently dips 40 degrees to 50 degrees to the SE and appears to be related to the eclogitized Hess conjugate.