Abstract: We collected earthquake moment tensors of Chinese mainland and its vicinity in 1900~ 2013, and gathered source parameters, surface ruptures and displacements of 70 earthquakes with magnitude equal to or greater than 7.0. According to thecollecteddata, we divided these large earthqua kes into three parts. Part A contains earthquakes with sur-face ruptures and displacements, Part B contains eart hquakes without displacements and Part C contains earthquakes without any of these data. We simulated the displacement dis-tribution with the triangular model for Part B and C earthquakes without displacements. Then, we segmented these large eart hquakes with displacements and relationship between surface ruptures and grids used in this article. Finally, we determined the deformation model from the segmented and unsegmented earthquake data and modified the bicubic spline function. The results show that①The reasonability and spatial consistency of de formation model are improved with earthquake segmentation, deformation model is more continuity and comparable with geologic and geodetic results in Himalaya thrust fault zones,deformation in the Tarim basin and the Altyn Tagh fault zones are decreased which are comparable with their low seismicity. The directionof compressional deformation in Gobi-Altai is adjusted from SE to NE and its extensional direction is changed from NE to NW. The extensional deformation in the Ordos block is diminished obviously. ②The earthquakes account for 30~ 50 percent of expected motion of India relative to Eurasia de termined from the geologic data, with the missing component of 20 mm/a, which may . contain aseismic deformation such as fault creep and folds, the undetected or missing of earthquake data and elastic strain energy released by potential earthquakes.

Key words: Bicubic spline function, Earthquake segmentation, Strain rate field, Surface subr rupture