WGS84 1
WGS84 1 : An acronym for World Geodetic System, 1984. A system of coordinates conventionally used and distributed by GPS as GPS coordinates. Includes an ellipsoid with inverse flattening 1/f = 298.25722 and semi-major axis = 6378.137 km (DMA, 1987). The flattening f is defined as the difference between the equatorial and polar radius of the Earth divided by the former. All seismic stations should report their positions in WGS84 coordinates. See Feigl (2002)