利用大地水准面起伏模拟琉球海沟洋坡岩石圈的挠曲

USING GEOID TO MODEL SEAWARD LITHOSPHERIC FLEXURE OF THE RYUKYU TRENCH

利用大地水准面起伏模拟琉球海沟南、中、北段岩石圈的挠曲 ,经非线性最小二乘拟合 ,得到琉球海沟洋坡各段岩石圈的有效弹性厚度 (Te)。模拟结果表明 ,琉球海沟洋坡的Te中段小 ,南北段大 ;南北段相比 ,南段小 ,北段大 ;与其他海沟相比琉球海沟洋坡的Te非常小。不同的Te值表明俯冲板片与岛弧之间不同的耦合程度 ,为进一步研究西太平洋边缘沟 弧

Seaward lithospheric flexure of deep ocean trenches is evident in Seasat altimeter observation of the marine geoid. We used geoid formula from elastic plate theory to fit seaward lithospheric flexure of the Ryukyu Trench after least squares adjustments,and got estimates of model parameter: effective lithospheric thickness (T_(e)).As a result, along the Ryukyu Trench, T_(e) is smaller in the middle section than in the south and north sections, and bigger in the north than in the south. T_(e) is smaller than those of the other trenches in the world. This result will help the future study on the trench-arc-basin system of the West Pacific.