全球1°×1°海洋岩石圈有效弹性厚度模型

A 1°×1° Model for Lithospheric Effective Elastic Thickness over Global Seafloor

利用岩石圈挠曲均衡原理,联合海底地形模型和测高重力异常数据,采用滑动窗口导纳技术(moving window admittance technique,MWAT)计算了全球1°×1°海洋岩石圈有效弹性厚度模型。结果表明,海洋岩石圈有效弹性厚度总体较小,10km以下区域约占70%,15km以下约占85.4%,均值和标准差分别约为10km和6.7km。岩石圈有效弹性厚度20km以上的区域主要位于海沟外隆地区,洋中脊岩石圈有效弹性厚度一般小于5km;被动大陆边缘,如澳洲大陆南缘,岩石圈有效弹性厚度一般也较小;太平洋的海山密集分布地区,岩石圈有效弹性厚度一般为10~20km。

Based on the flexural isostasy model of the lithosphere, a 1°×1° model of lithospheric effec- tive elastic thickness over the global seafloor was calculated by the Moving Window Admittance Tech- nique （MWAT） method, using bathymetry and gravity anomalies derived from altimetry data. The results show that the lithospheric effective elastic thickness over the seafloor is generally small. About 70% of the seafloor has an effective elastic thickness of lower than 10 kin, and 85.4% are lower than 15 kin. The mean and standard deviation of effective elastic thickness is about 10 km and 6.7 km, re- spectively. The lithosphere with an effective elastic thickness larger than 20 km is mainly located in out rise of the trenches. The lithosphere over the mid-ocean ridge usually has effective elastic thick- ness of lower than 5kin. The strength of lithosphere over the passive continental margin, such as the southern margin of the Australian continent, is also weak. The effective elastic thickness of litho- sphere over the seamount area of the Pacific is about 10 to 20 kin.