岩石圈有效弹性厚度估算方法研究进展  

Estimation of the effective elastic thickness of the lithosphere: progress and prospects

作　　者：侍文 陈石[1,2] 韩建成 贾路路 Shi Wen;Chen Shi;Han Jiancheng;Jia Lulu(Institute of Geophysics,China Earthquake Administration,Beijing 100081,China;Beijing Baijiatuan Earth Sciences National Observation and Research Station,Beijing 100095,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

出　　处：《地球与行星物理论评》2022年第3期301-315,共15页Reviews of Geophysics and Planetary Physics

基　　金：国家自然科学基金青年资助项目(42104090);国家自然科学基金联合基金及面上资助项目(U1939205,41774090);中国地震局地球物理研究所基本科研业务专项资助项目(DQJB20K44,DQJB20K31)。

摘　　要：岩石圈有效弹性厚度(T_(e))是度量岩石圈力学强度的一个定量指标,是研究岩石圈大规模构造的有力工具.研究岩石圈有效弹性厚度,对于了解岩石圈力学强度及其横向变化特征、重力均衡状态、热状态、地壳厚度变化、岩石圈内部圈层耦合关系和壳幔流变结构等信息具有重要作用.本文介绍了岩石圈有效弹性厚度的研究背景和基本估算原理,并总结了国内外岩石圈有效弹性厚度估算方法的研究进展.同时,本文也详细论述了这些岩石圈T_(e)估算方法的工作原理,并分析比较了它们的优缺点.目前估算岩石圈T_(e)的方法主要包括:正演法、谱分析方法(包括:导纳法和相关性法)和屈服应力包络法.近年来,随着数字信号处理技术的不断发展,谱分析方法已逐渐成为最流行的岩石圈T_(e)估算方法.地形和重力异常数据的功率谱估计是谱分析方法的关键环节,这些功率谱估计结果的质量会直接影响岩石圈T_(e)计算结果的准确性和可靠性.因此,周期图法、最大熵法、多窗谱分析、小波谱分析等在数字信号处理领域中应用效果较好的功率谱估算技术,逐渐被引入到了岩石圈有效弹性厚度的计算中,以获取准确可靠的T_(e)计算结果.最近,T_(e)各向异性的研究也取得了一定的成果,为岩石圈垂直受力状态、不同圈层耦合程度以及岩石圈变形和流变特性的研究提供了重要科学依据.最后,本文提出了未来值得深入的岩石圈有效弹性厚度研究方向,可为开展相关研究提供有益参考.The lithospheric strength is a key factor in controlling the lithosphere dynamics and deformations.The effective elastic thickness(T_(e)) of the lithosphere can always be used to address the lithospheric strength.Hence, it is a powerful tool for studying the large-scale lithospheric structure. Estimates of T_(e) over both continent and ocean are important for understanding the lithospheric strength with its lateral variations, crustal gravity isostatic state, lithospheric thermal state and rheological structure, and the coupling at the lithosphere-asthenosphere boundary. This article summaries the background of T_(e) estimation and reviews the domestic and overseas research progress on the estimation methods. The main methods for estimating T_(e) include forward modeling of deformations, spectral techniques(i.e., admittance and coherence) based on the cross-spectral analysis of the gravity and topography data, and direct estimations of T_(e) based on the yield strength envelope. The method of deformation forward modeling estimates T_(e) from the optimal lithospheric deflection model, with which the calculated theoretical gravity anomalies best fit the observed ones. The spectral technique calculates T_(e) through analyzing the relationship between observed gravity and topography data in the spatial wavenumber domain, including admittance and coherence methods. The admittance method operates the T_(e) estimation basically based on the spectrum ratio of the gravity to topography signals, while the coherence method works by examining the variation characteristics of the relationship between those two signals in wavenumber domain. Under long-wavelength loading, the lithosphere tends to act as a regional isostatic equilibrium mode. In this model, the lithosphere deflected and the gravity anomaly could be completely related to the topography, i.e., the correlation between those two is close to 1. In contrast,under short-wavelength loading, the lithosphere usually does not deflect due to the lithospheric strength, hence

关 键 词：岩石圈 有效弹性厚度 导纳法 相关性法 力学各向异性 

分 类 号：P313[天文地球—固体地球物理学]