Because of the last re-measurement interval is only a
half-year, the precision of signal must be very poor if
we only use the GPS data measured in 2004 and 2005.
Thus, we suppose that there is a regular variation of
crust deformation from 1999 to 2005, and an
increasing component due to the great earthquake with
Ms8.7 in Indian Ocean. So we can make a set of
equations with all the GPS data of 1999, 2001, 2004
and 2005, with which we can calculate out the
increasing vectors for each GPS point. Based on
further analysis of the increasing component, the
estimation of the influence of the great earthquake on
China can be made.