3D structure of the asthenosphere beneath China and adjacent land and sea areas and its interaction with the lithosphere

Abstract： This paper discusses the 3D structure features of the asthenosphere beneath China and adjacent land and sea areas based on a systematic tectonic analysis of the 3D velocity structure by using seismic surface wave tomographic imaging. Both high-velocity blocks and low-velocity anomalies were discovered in the asthenosphere of the region, indicating the existence of vertical and lateral heterogeneities in the asthenosphere. Study of the 3D geometric structure of the low-velocity anomalies in the asthenosphere suggests that the anomaly beneath the South China Sea asthenosphere is composite mushroom-shaped. According to this finding, combined with the mantle body wave tomographic image, it is concluded that a giant composite mushroom-shaped low-velocity mantle plume might occur at over 2000 km depth in the region. In addition, this paper approaches the problem related to the impact of the asthenosphere on the lithospheric structure and their interaction.