Vol.46-2 ABSTRACT1

Abstract

A new data set of Global Positioning System (GPS) stations established by the Geographical Survey Institute (GSI) is analyzed for aiming both precise determination of the motion of the Pacific plate and an estimation of the intra-plate deformation. Although the analyzed time interval is not long enough (from January 1997 to May 1999), preliminary results have been obtained as follows. The velocities determined by the new GPS stations are consistent with those of existing GPS stations of the International GPS Service for Geodynamics (IGS), and the upper-limit of the mean intra-plate deformation of the Pacific plate for two and half years is estimated to be 5 mm/yr for the baseline length of about 7000 km. The degree of the upper-limit for the intra-plate deformation is consistent with the recent estimation of the deformation of the Pacific plate derived from a observation for geological time scale.