中文摘要：

根据GPS观测的Tokachi—Oki地震及强余震引起的地表位移，采用基于敏感性探测的方法反演了两次地震分别引起的断层滑移。反演过程中，考虑了更切合实际的分层地球模型和断层面几何形状。主震和强余震滑移量的最大值分别为3．07m和0．33m，相应的矩震级分别为Mw7．94和Mw7．1，与地震波形反演的结果基本一致。另外，从主震和强余震的滑移分布来看，强余震的滑移主要分布在主震破裂较小的区域，一种合理的解释是，主震的破裂过程增加了邻区断层面上的能量积累，导致了强余震的发生。

英文摘要：

With the observed GPS coseismic displacements of Tokachi-Oki Earthquake and its biggest aftershock, we derive the coseismic slip distributions of the two earthquakes using SBIF （sensitivity-based iterative fitting） method. A more real fault geometry and layered Earth model were considered in the inverted process. As results shown, the maximal slips of the main shock and the biggest aftershock are 3.07 m and 0.33 m respectively. The corre- sponding moment magnitude scale are Mw 7.94 and Mw 7.1, which is consistent with the seismic result. In addition, the slip of the aftershock is mainly located at the place the coseis- mic slip of the main shock is lower, which perhaps indicate that the stress of surrounding re- gion is enlarged by the coseismic slip of the main shock and thus trigger the biggest after- shock.