地球与行星物理论评（中英文）2026，Vol.57Issue(6)：663-675,13.DOI:10.19975/j.dqyxx.2026-019
岩石圈-软流圈边界结构与板块运动速率的相关性研究
The correlation between lithosphere-asthenosphere boundary structure and plate motion velocity
摘要
Abstract
The lithosphere-asthenosphere boundary(LAB),defined seismologically as the interface separating the high-velocity lithosphere from the low-velocity asthenosphere,records key information about the distinct physi-cal and chemical properties of these two layers and their dynamic interactions.Plate tectonic theory holds that rigid lithospheric plates move horizontally over the weaker,ductile asthenosphere,with observed global plate velocities ranging from 1 to 10 cm per year.This substantial variability is widely considered a direct manifestation of litho-sphere-asthenosphere interactions.However,whether systematic relationships exist between LAB structural charac-teristics and plate motion rates remains an open question that is fundamental to understanding plate-driving forces.To address this question,this study focuses on oceanic regions and oceanic-continental transition zones,where lithospheric structure is relatively simple compared to continental interiors.Using teleseismic S-wave receiver functions from 107 globally distributed broadband seismic stations,we applied a consistent grid-search inversion methodology to systematically extract LAB structural parameters—including depth,shear-wave velocity drop mag-nitude,and transition zone thickness—beneath each station.This uniform processing approach minimizes biases in-herent in compiling disparate results from previous studies.The obtained LAB parameters were then analyzed for correlation with absolute plate motion rates from the NUVEL-1A model.Our results reveal three principal findings.First,LAB depth in mature oceanic regions closely follows the 1 100℃isotherm predicted by the plate cooling model,suggesting that the seismically defined LAB may correspond to a rheological boundary where thermally ac-tivated creep becomes dominant.Second,and most significantly,both the magnitude and the gradient of the shear-wave velocity drop across the LAB exhibit strong positive correlations with plate velocity,with Pearson correla-tion coefficients of r=0.686 and r=0.650,respectively.We interpret this as evidence for widespread low-viscosity melt or volatiles within the asthenosphere.Greater velocity drops imply higher melt fractions,which substantially reduce asthenospheric viscosity and promote mechanical decoupling between the lithosphere and underlying mantle.This decoupling effectively lowers the basal shear resistance acting on the plate,enabling higher plate velo-cities.Third,the thickness of the LAB transition zone,consistently measured at less than 30 km across all stations,shows no statistically significant correlation with plate velocity(r=-0.141),indicating that interface sharpness is not a primary control on plate kinematics.This study provides new seismological constraints on lithosphere-as-thenosphere interactions and offers observational support for models in which plate motion is modulated by mantle viscosity and coupling conditions at the LAB.However,several limitations must be acknowledged.The current dataset has uneven global coverage,and the vertical resolution of S-wave receiver functions(typically 5-10 km)imposes limits on parameter precision.Furthermore,our grid-search approach,while systematic,may not fully capture the full complexity of LAB structure.Therefore,the observed relationships,particularly the null cor-relation with thickness,warrant validation through future studies incorporating denser station coverage,multi-fre-quency receiver function analysis,and joint inversion with complementary datasets such as surface wave disper-sion or body wave tomography.Despite these limitations,our findings provide a step toward quantitatively linking plate-scale dynamics with the seismic structure of the upper mantle.关键词
岩石圈-软流圈边界结构/S波接收函数/板块运动速率/岩石圈-软流圈相互作用Key words
lithosphere-asthenosphere boundary/S-wave receiver function/plate motion rate/lithosphere-asthenosphere interaction分类
天文与地球科学引用本文复制引用
杨子煜,陈凌,徐涛,兰海强..岩石圈-软流圈边界结构与板块运动速率的相关性研究[J].地球与行星物理论评（中英文）,2026,57(6):663-675,13.基金项目
国家重点研发计划(2023YFF0803203) （2023YFF0803203）
国家自然科学基金资助项目(42288201) Supported by the National Key Research and Development Program of China(Grant No.2023YFF0803203),and the National Natu-ral Science Foundation of China(Grant No.42288201) （42288201）
