INTERSEISMIC DEFORMATION DATA AS A GEODETIC PRECURSOR FOR EARTHQUAKE PREDICTION CASE STUDY: INTERSEISMIC GPS DATA OF SEPTEMBER, 27, 2003, CHUYA EARTHQUAKE, ALTAI REGION

Interseismic data in Altai GPS network for geodetic earthquake precursors have been analyzed. The data gathered in period of 2000 to 2003 before September 27 2003, Chuya earthquake. The methodology for data analysis have been divided into; (i) interpolation of discrete horizontal velocity field by Delaunay triangulation in finite element scope, (ii) calculation of non translational deformation tensor, eigenvalues, eigenvectors, strain tensor, differential rotation tensor and several additional deformation parameters, (iii) using geodetic moment rate equations to convert the surface deformation data to moment rate. Based on deformation analysis in the vicinity of the earthquake location, before the event, the eigenvectors have been unified in the same direction that indicates the maximum deformation. If we assume a linear elastic material the principal deformation axes are in the maximum stress direction. Based on deformation parameters approximately 40% of maximum strain, 20% of dilatation, 50% of pure shear, 40% of simple shear, 50% of total shear and 50% of differential rotation accumulation occur in triangle 1 through triangle 5 in the vicinity of earthquake location. This study utilizes Savage and Simpson (1997) to help qualify the moment rate from GPS deformation data. We concluded about 45% of the geodetic moment rate accumulation in the southern Altai GPS network occurs in triangles 1 to 5 which lie around the Altai earthquake location.