Horizontal Velocities of Antarctic Stations
The motion of the tectonic plates is hard to measure. Even the fastest plates only move at 7 or 8 cm/year. The Antarctic Plate is moving quite slowly but the small changes in station location can now be measured using state-of-the art GPS instruments and processing technology with sufficient accuracy to determine plate motion.
This motion is determined relative to a fixed reference frame. An improved reference frame has recently been published so the GPS station locations in Antarctica may be determined more accurately. These locations are changing over time, the stations are moving horizontally and vertically. The map below shows how the direction and speed (proportional to length of arrow) of GPS stations. If these stations are re-visited, the plate motion can be determined more accurately. Vertical motions (not shown) are especially important as these are affected by ice melting which changes the load of the ice-sheets on the continents.
Horizontal station velocities from the SCAR GPS network in Antarctica as a rigorous solution within a new release of the International Terrestrial Reference Frame, ITRF(Altamimi et al., 2002). The displayed rotation pole is a left-hand rotation (Dietrich et al., 2004).
Altamimi, Z., P. Sillard, C. Boucher (2002): ITRF2000: a new release of the International Terrestrial Reference Frame for Earth science applications. Journal of Geophysical Research, 107 (B10), 2214 (doi:10.1029/2001/JB000561).
Dietrich, R., A. Rulke J., Ihde, K. Lindner, H. Miller, W. Niemeier, H.-W. Schenke, G. Seeber (2004): Plate kinematics and deformation status of the Antarctic Peninsula based on GPS, Global and Planetary Change 42, 313-321.