利用重力场模型解算全球地幔对流应力场  

Calculating the Global Mantle Convection Stress Field Using Gravity Field Models

作　　者：蒋腾渊 李建成[1,2,3] 邹贤才 魏辉[1,2] JIANG Tengyuan;LI Jiancheng;ZOU Xiancai;WEI Hui(Hubei Luojia Laboratory,School of Geodesy and Geomatics,Wuhan University,129 Luoyu Road,Wuhan 430079,China;Key Laboratory of Geospace Environment and Geodesy,Ministry of Education,Wuhan University,129 Luoyu Road,Wuhan 430079,China;Central South University,932 South-Lushan Road,Changsha 410083,China)

机构地区：[1]武汉大学测绘学院湖北珞珈实验室,武汉430079 [2]武汉大学地球空间环境与大地测量教育部重点实验室,武汉430079 [3]中南大学,长沙410083

出　　处：《大地测量与地球动力学》2024年第10期1071-1075,共5页Journal of Geodesy and Geodynamics

基　　金：国家自然科学基金(42388102,42192533,U23A2028);中央高校基本科研业务费专项(2042023kfyq01);国家重点研发计划(2021YFB2300403)。

摘　　要：在利用Runcorn模型确定全球地幔对流应力场的研究中,扰动位系数是关键参数之一。在以往研究中,该参数阶次的选取缺乏定量准则,本文引入点质量源法中场源深度与扰动位系数阶次的关系方程,初步对Runcorn模型中截止阶次进行限定。基于该思路,场源深度为30 km的地幔对流应力场应使用2~213阶扰动位系数推算。采用EGM2008地球重力场模型(2~213阶)解算全球地幔对流应力场,并与近8 a内深度大于30 km的M5.5以上地震的震中分布进行比较。结果表明,与板块边界重合的高应力区域和地震震中的分布有较好的对应关系,说明地幔对流可能通过控制板块间汇聚、拉张或错动,进而控制该地区地震的发生。此外,对3处地震发生频数较高的典型区域(欧亚-菲律宾板块边界等)的地幔对流应力及其构造背景进行分析,结果与前人研究结论一致。最后,通过与前人研究结论(2~8阶)进行对比发现,本文解算结果(2~213阶)在太平洋板块西南缘等有较大地震发生的板块边界具更多高地幔对流应力细节,这些地震的发生可能受到小尺度地幔对流的控制。The perturbation potential coefficient is one of the key parameters in using the Runcorn model to determine the global mantle convective stress field.In previous studies,there was a lack of quantitative criteria for selecting the order of this parameter.This paper introduces the relationship equation between the depth of the field source and the order of the disturbance potential coefficient in the point mass source method,and preliminarily limits the cutoff order in the Runcorn model.Based on this idea,the mantle convective stress field with a source depth of 30 km should be calculated using the 2 to 213 orders perturbation potential coefficients.This article uses the EGM2008 Earth Gravity Field Model(2 to 213 orders) to calculate the global mantle convective stress field and compares it with the epicenter distribution of earthquakes with a magnitude of 5.5 or above in the past 8 years.The results indicate that high stress areas that coincide with plate boundaries have a good correspondence with the distribution of earthquake epicenters,indicating that mantle convection may control the occurrence of earthquakes in the region by controlling inter plate convergence or tension.In addition,this article analyzes the mantle convective stress and its tectonic background in three typical regions with high frequency of earthquakes(such as the Eurasian Philippine Plate),and the results are consistent with previous research.Finally,by comparing with previous results(2 to 8 orders),the results obtained in this paper(2 to 213 orders) reveal more details of high mantle convection stress at plate boundaries with larger earthquakes occurring at the southwestern edge of the Pacific Plate.This paper suggests that the occurrence of these earthquakes may be controlled by small-scale mantle convection.

关 键 词：地幔对流 应力场 重力模型 EGM2008 卫星重力 

分 类 号：P312[天文地球—固体地球物理学] P315[天文地球—地球物理学]