High‐Resolution Imaging of Lithosphere‐Asthenosphere Structure in Northeast China Using Eikonal Tomography With Physics‐Informed Deep Learning

Abstract

In this study, we develop a 3D S‐wave velocity model extending to 120 km depth beneath Northeast China, featuring high resolution for the crust and uppermost mantle, based on physics‐informed neural network framework for eikonal tomography. Notably, this model provides a characterization of the transitional lithosphere‐asthenosphere boundary (LAB) beneath the volcanic regions, while also illuminating its connections to the formation of Quaternary intraplate volcanoes in the region. Key observations include a prominent large‐scale high‐velocity anomaly beneath the Songliao Basin (SLB), which suggests a thicker lithosphere in that area. In addition, we identify undulations in the LAB, as well as diverse low‐velocity features underlying the volcanoes. Drawing from a schematic representation of lithospheric and upper mantle convection, we interpret these patterns as stemming from regional variations in the water‐carbon cycle and lithospheric thickening within the SLB. For instance, inputs from the deep Big Mantle Wedge not only promote lithospheric thickening beneath the SLB, but also enhance asthenospheric mobility, facilitating sodic volcanism in the southeastern and western sectors. In contrast, the Wudalianchi (WDLC) and Nuominhe (NMH) volcanoes, which lack intense deep convection, produce potassic lavas instead. Overall, these insights improve our understanding of intraplate volcanic mechanisms in this region.