沙茨基海隆重力均衡的三维导纳分析  

3D ADMITTANCE ANALYSIS FOR GRAVITY ISOSTASY ON SHATSKY RISE

作　　者：胡敏章[1,2] 李建成[2] 李辉[1] 邢乐林[1,2] 

机构地区：[1]中国地震局地震研究所(地震大地测量重点实验室),武汉430071 [2]武汉大学测绘学院,武汉430079

出　　处：《大地测量与地球动力学》2014年第2期14-17,22,共5页Journal of Geodesy and Geodynamics

基　　金：中国地震局地震研究所重点所长基金(IS201326125);国家自然科学基金(41204019;41304003)

摘　　要：在频域内,采用三维导纳分析技术,联合重力异常和海底地形数据,分别以Airy均衡模型、挠曲均衡模型为参考,研究了沙茨基海隆的重力均衡机制。根据Airy均衡模型的分析表明,沙茨基海隆区域的洋壳平均厚度为15 km,Tamu海山的Moho面深度为约26 km,与地震波研究结果一致。根据挠曲均衡模型的分析表明,沙茨基海隆的岩石圈有效弹性厚度为1～5 km,属于＂On Ridge＂型海底构造。顾及地形及洋壳底部物质载荷作用的分析表明,沙茨基海隆地区底部载荷的规模约为地形的50%,平均深度约20 km。沙茨基海隆在很大程度上,可能是被底部低密度体的浮力作用支撑的。In frequency domain,the gravity isostasy on Shatsky Rise was studied by 3D admittance analysis of gravity anomalies and bathymetry,referenced to Airy and Flexural isostatic models respectively. According to Airy model,it indicates that the mean crust thickness of Shatsky Rise is about 15 km,and the depth of Moho discontinuity beneath Tamu massif is about 26 km,which is consistent with the result that given by seismic studies. According to flexural isostatic model,it shows that the effective elastic thickness of lithosphere around Shatsky Rise is 1 ～ 5km. That means the rise is an ＂On Ridge＂structure. Taking into account both the topography and material loading at the bottom of the crust,the result shows that the amplitude of material loading at the bottom of the crust is about50 % of the topography,and the average loading depth is 20 km. Shatsky Rise may be supported by the buoyancy of bottom loading mainly.

关 键 词：沙茨基海隆 重力均衡 三维导纳分析 Airy均衡模型 挠曲均衡模型 

分 类 号：P312.3[天文地球—固体地球物理学]