Distance variations between laser ranging stations derived from LAGEOS tracking data

The results obtained by the DGFI analysis center for the MERIT campaign have demonstrated that from LAGEOS laser ranging data the relative positions of the globally distributed tracking stations can be evaluated with an accuracy of a few centimeters. It therefore seemed promising to investigate the stability of tracking station coordinates over a period of several years in order to detect interstation distance variations due to global horizontal deformations of the Earth's surface. The investigation focussed on a selected number of stations which have a good tracking data coverage over the 1980 – 1984 time span. Annual geocentric coordinates of these stations were estimated. From the coordinates spherical distances between stations on five different lithospheric plates were derived and the changes in length from year to year were investigated.