【摘要】 本文根据大地测量数据得到过去50年左右阿尔泰山富蕴区域形变场,破裂带中段的相对位移最大,平均速率达6mm/a,总体上表现为沿断裂的走滑运动特征.该形变场可以用1931年富蕴8级地震的震后黏弹性松弛模型进行模拟,反演得到下地壳黏滞系数为1.6×1019~7.9×1019Pa.s,上地幔黏滞系数为1.6×1018~6.3×1019Pa.s,与华北、Nevada等地区利用震后变形资料推算的黏度基本一致.根据该地区最佳黏弹性分层模型,最近五十年由于岩石圈下部应力松弛引起的地震破裂带两侧最大水平速率约为4mm/a.我们的研究表明:大陆7~8级大震在几十年后仍可能有可观的地表变形,GPS监测得到的现今变形场可能包含震后变形成分.更多还原

【Abstract】 Regional horizontal deformation in Fuyun Altay in the past 50 years is obtained from geodetic data,the maximum relative displacement is at the middle rupture section with an average relative velocity up to about 6mm/a,manifesting strike slip character on the whole.The regional deformation can be modeled using postseismic viscoelastic relaxation models caused by M8 Fuyun earthquake in 1931,and the best fit lithospheric viscosities are 1.6×10¹⁹～7.9×10¹⁹Pa\5s for lower crust and 1.6×10¹⁸～6.3×10¹⁹Pa\5s for the upper mantle,which are consistent with other regions,for example,North China and Nevada.According to the best fit lithospheric rheological model,the maximum horizontal velocity along the rupture in the past 50 years caused by the postseismic viscoelastic relaxation was about 4 mm/a.This study shows that there may be significant surface deformation in the current crust velocity field caused by M7～8 earthquake several decades ago, which can be monitored by modern GPS.更多还原