Structure and Dynamics of Lithosphere and Asthenosphere in Asia: A Seismological Perspective

Knowledge of lithospheric structure is essential for understanding the impact of continental collision and oceanic subduction on surface tectonic configurations. Full-waveform tomographic images reveal lateral heterogeneities and anisotropy of the lithosphere and asthenosphere in Asia. Estimating lithospheric thickness from seismic velocity reductions at depth exhibits large variations underneath different tectonic units. The thickest cratonic roots are present beneath the Sichuan, Ordos, and Tarim basins and central India. Radial anisotropy signatures of 11 representative tectonic provinces uncover the different nature and geodynamic processes of their respective past and present deformation. The large-scale continental lithospheric deformation is characterized by low-velocity anomalies from the Himalayan Orogen to the Baikal rift zone in central Asia, coupled with the post-collision thickening of the crust. The horizontal low-velocity layer of similar to 100-300 km depth extent below the lithosphere points toward the existence of the asthenosphere beneath East and Southeast Asia, with heterogeneous anisotropy indicative of channel flows.

Automated summary

Knowledge of lithospheric structure is crucial to comprehend how continental collision and oceanic subduction affect surface tectonic configurations. By using full-waveform tomographic images, scientists have discovered lateral heterogeneities and anisotropy in the lithosphere and asthenosphere of Asia. Estimations of lithospheric thickness based on seismic velocity reductions have shown significant variations among different tectonic units. The thickest cratonic roots are found beneath the Sichuan, Ordos, and Tarim basins, as well as central India. Radial anisotropy signatures from 11 representative tectonic provinces reveal the diverse nature and geodynamic processes of their past and present deformations. The extensive deformation of the continental lithosphere is characterized by low-velocity anomalies stretching from the Himalayan Orogen to the Baikal rift zone in central Asia, accompanied by crustal thickening after collision. The presence of a horizontal low-velocity layer at depths of approximately 100-300 km beneath the lithosphere suggests the existence of the asthenosphere beneath East and Southeast Asia, with varying anisotropy indicative of channel flows.