Applications of Geodesy to Geodynamics: 3. Tectonic Plate Movements and Crustal Deformations (Space Techniques)

Abstract

The use of space techniques for determining tectonic motions can be divided conveniently into two parts. One involves measurements at separations of a few hundred kilometers or more where the accuracy achievable by space techniques appears higher than can be expected by reasonable improvements of present ground techniques. The goal of such measurements can be thought of as the establishment of a worldwide geodynamics monitoring network consisting of perhaps 200 points at which measurements are made by mobile stations plus a few points where fixed stations are operated. Fixed stations are useful for monitoring the earth's rotation as well as for serving as reference points for the mobile station measurements. In addition to determining plate tectonic motions and large‐scale distortions within plates, some points at spacings of a few hundred kilometers around seismic zones would provide a control framework for measurements made within the zones and at nearby points by either ground techniques or other space techniques. The mobile station development work now appears to be far enough along so that plans are being made for establishing the first regular measurement program to determine roughly 100 points per year. The scientific benefits from such programs are expected to be large, even within the first few years.