Datasets and Model for "Age-Independent Oceanic Plate Thickness and Asthenosphere Melting from SS Precursor Imaging"

<p>The Earth&rsquo;s asthenosphere is a mechanically weak layer characterized by low seismic&nbsp;velocity and high attenuation. The nature of this layer has been strongly debated. In this&nbsp;study, we process twelve years of seismic data recorded at the global seismological network&nbsp;(GSN) stations to investigate SS waves reflected at the upper and lower boundaries of this&nbsp;layer in global oceanic regions. We observe strong reflections from both the top and the&nbsp;bottom of the asthenosphere, dispersive across all major oceans. The average depths of&nbsp;the two discontinuities are 120 km and 255 km, respectively. The SS waves reflected at the&nbsp;lithosphere and asthenosphere boundary are characterized by anomalously large amplitudes,&nbsp;which require &sim;12.5% reduction in seismic velocity across the interface. This large velocity&nbsp;drop can not be explained by a thermal cooling model but indicates 1.5%-2% localized melt&nbsp;in the oceanic asthenosphere. The depths of the two discontinuities show large variations,&nbsp;indicating that the asthenosphere is far from a homogeneous layer but likely associated with&nbsp;strong and heterogeneous small-scale convections in the oceanic mantle. The average depths&nbsp;of the two boundaries are largely constant across different age bands. In contrast to the half&nbsp;space cooling model, this observation supports the existence of a constant-thickness plate&nbsp;in oceanic regions with a complex and heterogeneous origin.&nbsp;This repository contains four datasets and one reference earth model from this study.</p>