nuvel_1_plates.orig: original lon/lat boundaries of plates
  that was cyber-floating with a NUVEL-1A package we received
  back in 1999; we don't know the original source

nuvel_1_plates: this fixes a couple of minor errors in
  nuvel_1_plates.orig to make the plate boundary sections continuous

<plate-name>_plate: the sections of nuvel_1_plates put together
  so they form the boundary of the named plate (but the sections
  are not continuous)

<plate-name>.txt: single continuous plate boundary segment with
  lon/lat points going counterclockwise (courtesy of Jinwei Ren,
  China Seismological Bureau, Beijing, China)