青藏高原东北缘及邻区岩石圈力学强度的贝叶斯估计  

Bayesian inference for the lithospheric mechanical strength in the northeastern Qinghai-Tibet Plateau and its adjacent areas

作　　者：潘宇航 陈石[1,2] 侍文 孙玉军 李永波 董冬辉 PAN YuHang;CHEN Shi;SHI Wen;SUN YuJun;LI YongBo;DONG DongHui(Institute of Geophysics,China Earthquake Administration,Beijing 100081,China;Beijing Baijiatuan Earth Science National Observation and Research Station,Beijing 100095,China;Chinese Academy of Geological Sciences,Beijing 100037,China)

机构地区：[1]中国地震局地球物理研究所,北京100081 [2]北京白家疃地球科学国家野外科学观测研究站,北京100095 [3]中国地质科学院,北京100037

出　　处：《地球物理学报》2024年第6期2220-2231,共12页Chinese Journal of Geophysics

基　　金：国家自然科学基金(42022029,U1939205,41974095);中国地震局地球物理研究所基本科研业务(DQJB21R30)联合资助。

摘　　要：本文基于复合岩石圈挠曲均衡模型,利用布格重力异常和地形数据,采用重力导纳和相关函数联合反演方法,结合贝叶斯统计推理确定最优的岩石圈挠曲参数模型,获取了青藏高原东北缘岩石圈有效弹性厚度Te和载荷比F的空间分布特征及不确定性估计.在此基础上,本文分析了各个构造单元的差异性及其与强震活动的关系,并利用热-流变结构等资料,给出了构造运动可能的深部动力源.研究结果显示:青藏高原东北缘及邻区F呈现大面积低值分布,说明其现今岩石圈挠曲状态主要与地表载荷加载相关.此外,岩石圈有效弹性厚度Te存在显著差异,其力学强度差异与青藏高原向东挤出变形、热结构状态有一定对应关系.本文结果可为定量化研究青藏高原动力学问题提供有效的地球物理依据.This study employs a composite lithospheric flexure isostasy model,using Bouguer gravity anomalies and topographic data,to perform a joint inversion of gravity admittance and coherence functions.Using Bayesian statistical inference,the optimal lithospheric flexure parameter model was determined,allowing for the characterization of the spatial distribution and uncertainty estimation of the effective elastic thickness(Te)and load ratio(F)along the northeastern margin of the Tibetan Plateau.Building on this foundation,the paper analyzes the variability among different tectonic units and their relationship with seismic activity,incorporating data on thermal-rheological structure to propose potential deep drivers of tectonic movements.The results indicate that the region exhibits a widespread distribution of low F values,suggesting that the current lithospheric flexural state is primarily influenced by surface load.Furthermore,significant variability in effective elastic thickness(Te)reflects differences in mechanical strength,which correlate with the eastward extrusion deformation and thermal structural state of the Tibetan Plateau.The findings provide a geophysical basis for the quantitative study of the dynamics of the Tibetan Plateau.

关 键 词：青藏高原东北缘 岩石圈挠曲 有效弹性厚度 载荷比 贝叶斯估计 

分 类 号：P312[天文地球—固体地球物理学]