16 January 1998
Vol 279, Issue 5349

About The Cover

The high Andes near La Paz, Bolivia. The great Andean plateau has been forming for millions of years as the South American continent shortens as a result of the subduction of the oceanic Nazca plate beneath it. The global positioning system, which can measure the relative positions of sites thousands of kilometers apart to precisions of less than a centimeter, allows the shortening to be measured over only a few years. See 358. [Image: S. Stein]