Space-Age Geodesy: The NASA Crustal Dynamics Project

The NASA Crustal Dynamics Project has deployed satellite laser ranging (SLR) systems and very-long-baseline-interferometer (VLBI) systems for measurements of global and regional crustal motions and Earth rotation parameters. In 1984, the several year buildup of the network approached full capability. During 1984, the SLR systems measured 142 unique baselines between stations for the purpose of determining plate motion between the North American, Pacific, South American, Nazca, Australian, and Eurasian plates; 31 baselines for internal deformation of the same plates; and 9 baselines for regional deformation in the area of the western North American plate boundary. During 1984, the VLBI systems measured 24 baselines for plate motion between the North American, Pacific, and Eurasian plates; 37 baselines for internal deformation of the same plates; and 101 baselines for regional deformation in the area of the western North American plate boundary. Both the SLR and VLBI stations operated throughout the September 1983 to October 1984 international MERIT campaign of measurements of the Earth's polar motion and changes in rotation rate. NASA's future plans are to continue these measurements through at least 1990 and to initiate a joint NASA/ European SLR measurement campaign for determining regional crustal deformation in the Mediterranean area.