CRUSTAL DEFORMATIONS FROM SPARCE GEODETIC DATA

Abstract

During the last decade, the Higher Geodesy Laboratory of NTU and the Seismology Department of the Institut de Physique du Globe de Paris have carried out a research program concerning the evaluation of the tectonic behaviour of the Gulf of Corinth, in Greece, based on geodetic data. The area being one of the densely populated, seismically active parts of Greece, was considered suitable for monitoring deformations. Thus, a geodetic GPS control network of 193 points, spread over a broad area (of about 10000 km2) on both sides of the Gulf, was established within seven years. During this period several points were reoccupied. Thus the GPS data acquired are sparse both in space and time. In order to estimate the deformation over longer periods of time 142 of the network points were chosen to belong to the Hellenic triangulation network. In the present paper, statistically acceptable strain parameters are evaluated via a multi-epoch deformation model using GPS data alone as well as in combination with positional information from old geodetic surveys.